diff --git a/.travis.yml b/.travis.yml
index 9092eb7..de4a07f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,6 +21,7 @@ script:
 
 cache:
   - directories:
+    - test/tmp/cache
     - vendor
 
 notifications:
diff --git a/composer.json b/composer.json
index b4ed3ec..a1818c1 100644
--- a/composer.json
+++ b/composer.json
@@ -1,7 +1,7 @@
 {
     "name": "postcss/postcss",
     "type": "library",
-    "description": "Unifficial native PHP port of the PostCSS processor",
+    "description": "Unofficial native PHP port of the PostCSS processor",
     "keywords": [
         "css",
         "postcss",
@@ -32,4 +32,4 @@
         "issues": "https://github.com/mlocati/postcss/issues",
         "source": "https://github.com/mlocati/postcss"
     }
-}
\ No newline at end of file
+}
diff --git a/src/AtRule.php b/src/AtRule.php
index 3535fc0..e442898 100644
--- a/src/AtRule.php
+++ b/src/AtRule.php
@@ -5,8 +5,7 @@
 /**
  * Represents an at-rule.
  *
- * If it’s followed in the CSS by a {} block, this node will have
- * a nodes property representing its children.
+ * If it's followed in the CSS by a {} block, this node will have a nodes property representing its children.
  *
  * @example
  * $root = \PostCSS\Parser::parse('@charset "UTF-8"; @media print {}');
@@ -21,7 +20,7 @@
 class AtRule extends Container
 {
     /**
-     * The at-rule’s name immediately follows the `@`.
+     * The at-rule's name immediately follows the `@`.
      *
      * @example
      * $root  = \PostCSS\Parser::parse('@media print {}');
@@ -33,7 +32,7 @@ class AtRule extends Container
     public $name = null;
 
     /**
-     * The at-rule’s parameters, the values that follow the at-rule’s name but precede any {} block.
+     * The at-rule's parameters, the values that follow the at-rule's name but precede any {} block.
      *
      * @example
      * $root  = \PostCSS\Parser::parse('@media print, screen {}');
diff --git a/src/Comment.php b/src/Comment.php
index 6634d6c..b9f9f61 100644
--- a/src/Comment.php
+++ b/src/Comment.php
@@ -12,7 +12,7 @@
 class Comment extends Node
 {
     /**
-     * The comment’s text.
+     * The comment's text.
      *
      * @var string|null
      */
diff --git a/src/Container.php b/src/Container.php
index 0ff873b..f09222e 100644
--- a/src/Container.php
+++ b/src/Container.php
@@ -9,8 +9,8 @@
  *
  * @link https://github.com/postcss/postcss/blob/master/lib/container.es6
  *
- * @property Node|null $first The container’s first child (@example $rule->first == $rules->nodes[0]) )
- * @property Node|null $last The container’s last child (@example $rule->last == $rules->nodes[count($rules->nodes) - 1] )
+ * @property Node|null $first The container's first child (@example $rule->first == $rules->nodes[0]) )
+ * @property Node|null $last The container's last child (@example $rule->last == $rules->nodes[count($rules->nodes) - 1] )
  */
 abstract class Container extends Node
 {
diff --git a/src/Exception/CssSyntaxError.php b/src/Exception/CssSyntaxError.php
index 960d5f4..fb9df78 100644
--- a/src/Exception/CssSyntaxError.php
+++ b/src/Exception/CssSyntaxError.php
@@ -8,15 +8,14 @@
 /**
  * The CSS parser throws this error for broken CSS.
  *
- * Custom parsers can throw this error for broken custom syntax using
- * the {@link Node#error} method.
+ * Custom parsers can throw this error for broken custom syntax using Node->error method.
  *
  * PostCSS will use the input source map to detect the original error location.
- * If you wrote a Sass file, compiled it to CSS and then parsed it with PostCSS,
- * PostCSS will show the original position in the Sass file.
+ * If you wrote a Sass file, compiled it to CSS and then parsed it with PostCSS, PostCSS will show the original position in the Sass file.
  *
- * If you need the position in the PostCSS input
- * (e.g., to debug the previous compiler), use `error.input.file`.
+ * If you need the position in the PostCSS input (e.g., to debug the previous compiler), use `$error->input['file']`.
+ *
+ * @link https://github.com/postcss/postcss/blob/master/lib/css-syntax-error.es6
  */
 class CssSyntaxError extends Exception
 {
@@ -90,6 +89,9 @@ public function setMessage($message)
         $this->message = (string) $message;
     }
 
+    /**
+     * Updates the message.
+     */
     public function updateMessage()
     {
         $plugin = ($this->postcssPlugin instanceof PluginInterface) ? $this->postcssPlugin->getName() : (string) $this->postcssPlugin;
@@ -208,6 +210,11 @@ public function showSourceCode($color = null)
         return implode("\n", $output);
     }
 
+    /**
+     * {@inheritdoc}
+     *
+     * @see Exception::__toString()
+     */
     public function __toString()
     {
         $fqn = get_class($this);
diff --git a/src/LazyResult.php b/src/LazyResult.php
index 2985c2c..7376895 100644
--- a/src/LazyResult.php
+++ b/src/LazyResult.php
@@ -2,8 +2,9 @@
 
 namespace PostCSS;
 
-use React\Promise\Promise;
 use PostCSS\Plugin\PluginInterface;
+use React\Promise\Promise;
+use React\Promise\PromiseInterface;
 
 /**
  * A Promise proxy for the result of PostCSS transformations.
@@ -50,6 +51,18 @@ class LazyResult
      */
     protected $processing = null;
 
+    /**
+     * Current plugin index.
+     *
+     * @var int
+     */
+    protected $plugin;
+
+    /**
+     * @param Processor $processor
+     * @param mixed $css
+     * @param array $opts
+     */
     public function __construct(Processor $processor, $css, array $opts = [])
     {
         $this->stringified = false;
@@ -122,10 +135,9 @@ public function __get($name)
     }
 
     /**
-     * Processes input CSS through synchronous plugins
-     * and calls {@link Result#warnings()}.
+     * Processes input CSS through synchronous plugins and calls Result->warnings().
      *
-     * @return {Warning[]} warnings from plugins
+     * @return Warning[] warnings from plugins
      */
     public function warnings()
     {
@@ -133,12 +145,12 @@ public function warnings()
     }
 
     /**
-     * Alias for the {@link LazyResult#css} property.
+     * Alias for the LazyResult->css property.
      *
      * @example
-     * lazy + '' === lazy.css;
+     * (string) $lazy === $lazy->css;
      *
-     * @return {string} output CSS
+     * @return string output CSS
      */
     public function __toString()
     {
@@ -146,22 +158,18 @@ public function __toString()
     }
 
     /**
-     * Processes input CSS through synchronous and asynchronous plugins
-     * and calls `onFulfilled` with a Result instance. If a plugin throws
-     * an error, the `onRejected` callback will be executed.
+     * Processes input CSS through synchronous and asynchronous plugins and calls `onFulfilled` with a Result instance.
+     * If a plugin throws an error, the `onRejected` callback will be executed.
      *
      * It implements standard Promise API.
      *
-     * @param {onFulfilled} onFulfilled - callback will be executed
-     *                                    when all plugins will finish work
-     * @param {onRejected}  onRejected  - callback will be execited on any error
+     * @param callable $onFulfilled Callback will be executed when all plugins will finish work
+     * @param callable $onRejected Callback will be executed on any error
      *
-     * @return {Promise} Promise API to make queue
+     * @return Promise Promise API to make queue
      *
      * @example
-     * postcss([cssnext]).process(css).then(result => {
-     *   console.log(result.css);
-     * });
+     * (new \PostCSS\Processor([Cssnext::class]))->process($css)->then(function ($result) { echo $result->css; })->done();
      */
     public function then($onFulfilled, $onRejected)
     {
@@ -169,20 +177,18 @@ public function then($onFulfilled, $onRejected)
     }
 
     /**
-     * Processes input CSS through synchronous and asynchronous plugins
-     * and calls onRejected for each error thrown in any plugin.
-     *
+     * Processes input CSS through synchronous and asynchronous plugins and calls onRejected for each error thrown in any plugin.
      * It implements standard Promise API.
      *
-     * @param {onRejected} onRejected - callback will be execited on any error
+     * @param callable $onRejected Callback will be executed on any error
      *
-     * @return {Promise} Promise API to make queue
+     * @return Promise Promise API to make queue
      *
      * @example
-     * postcss([cssnext]).process(css).then(result => {
-     *   console.log(result.css);
-     * }).catch(error => {
-     *   console.error(error);
+     * (new \PostCSS\Processor([Cssnext::class]))->process($css)->then(function ($result) {
+     *   echo $result->css);
+     * })->catchError(function ($error) {
+     *   echo (string) $error;
      * });
      */
     public function catchError($onRejected)
@@ -193,6 +199,10 @@ public function catchError($onRejected)
         );
     }
 
+    /**
+     * @param \Exception $error
+     * @param PluginInterface|string $plugin
+     */
     public function handleError(\Exception $error, $plugin)
     {
         try {
@@ -216,6 +226,12 @@ public function handleError(\Exception $error, $plugin)
         }
     }
 
+    /**
+     * @param callable $resolve
+     * @param callable $reject
+     *
+     * @return mixed
+     */
     public function asyncTick($resolve, $reject)
     {
         if ($this->plugin >= count($this->result->processor->plugins)) {
@@ -228,7 +244,7 @@ public function asyncTick($resolve, $reject)
             $promise = $this->run($plugin);
             $this->plugin += 1;
 
-            if ($promise instanceof Promise) {
+            if ($promise instanceof PromiseInterface) {
                 $me = $this;
                 $promise->then(
                     function () use ($me, $resolve, $reject) {
@@ -249,6 +265,9 @@ function ($error) use ($me, $plugin, $reject) {
         }
     }
 
+    /**
+     * @return Promise
+     */
     public function async()
     {
         if ($this->processed) {
@@ -284,6 +303,11 @@ function () use ($me) {
         return $this->processing;
     }
 
+    /**
+     * @throws \Exception
+     *
+     * @return \PostCSS\Result
+     */
     public function sync()
     {
         if ($this->processed) {
@@ -292,7 +316,7 @@ public function sync()
         $this->processed = true;
 
         if ($this->processing) {
-            throw new \Exception('Use process(css).then(cb) to work with async plugins');
+            throw new \Exception('Use process($css)->then($cb) to work with async plugins');
         }
 
         if ($this->error) {
@@ -303,13 +327,20 @@ public function sync()
         for ($i = 0; $i < count($processor->plugins); ++$i) {
             $promise = $this->run($processor->plugins[$i]);
             if ($promise instanceof Promise) {
-                throw new \Exception('Use process(css).then(cb) to work with async plugins');
+                throw new \Exception('Use process($css)->then($cb) to work with async plugins');
             }
         }
 
         return $this->result;
     }
 
+    /**
+     * @param PluginInterface $plugin
+     *
+     * @throws \Exception
+     *
+     * @return mixed
+     */
     public function run(PluginInterface $plugin)
     {
         $this->result->lastPlugin = $plugin;
diff --git a/src/ListUtil.php b/src/ListUtil.php
index 72dc964..fde540e 100644
--- a/src/ListUtil.php
+++ b/src/ListUtil.php
@@ -67,7 +67,7 @@ public static function split($string, array $separators, $last = false)
      *
      * @param string $string Space-separated values
      *
-     * @return string[] Splitted values
+     * @return string[] Split values
      *
      * @example
      *
@@ -85,7 +85,7 @@ public static function space($string)
      *
      * @param string $string Comma-separated values
      *
-     * @return string[] Splitted values
+     * @return string[] Split values
      *
      * @example
      * \PostCSS\ListUtil::comma('black, linear-gradient(white, black)') //=> ['black', 'linear-gradient(white, black)']
diff --git a/src/MapGenerator.php b/src/MapGenerator.php
index 5528b74..82245f6 100644
--- a/src/MapGenerator.php
+++ b/src/MapGenerator.php
@@ -2,8 +2,8 @@
 
 namespace PostCSS;
 
-use PostCSS\SourceMap\Consumer\Consumer;
 use PostCSS\Path\NodeJS as Path;
+use PostCSS\SourceMap\Consumer\Consumer;
 
 /**
  * @link https://github.com/postcss/postcss/blob/master/lib/map-generator.es6
@@ -45,6 +45,11 @@ class MapGenerator
      */
     protected $map = null;
 
+    /**
+     * @param callable $stringify
+     * @param Root $root
+     * @param array $opts
+     */
     public function __construct(callable $stringify, Root $root, array $opts = [])
     {
         $this->stringify = $stringify;
@@ -53,6 +58,9 @@ public function __construct(callable $stringify, Root $root, array $opts = [])
         $this->opts = $opts;
     }
 
+    /**
+     * @return bool
+     */
     public function isMap()
     {
         if (isset($this->opts['map'])) {
@@ -64,6 +72,9 @@ public function isMap()
         }
     }
 
+    /**
+     * @return PreviousMap[]
+     */
     public function previous()
     {
         if ($this->previousMaps === null) {
@@ -82,6 +93,9 @@ public function previous()
         return $this->previousMaps;
     }
 
+    /**
+     * @return bool
+     */
     public function isInline()
     {
         if (isset($this->mapOpts['inline'])) {
@@ -109,6 +123,9 @@ public function isInline()
         }
     }
 
+    /**
+     * @return bool
+     */
     public function isSourcesContent()
     {
         if (isset($this->mapOpts['sourcesContent'])) {
@@ -151,7 +168,7 @@ public function setSourcesContent()
         $me = $this;
         $already = [];
         $this->root->walk(function (Node $node) use ($me, &$already) {
-            if ($node->source) {
+            if ($node->source && isset($node->source['input'])) {
                 $from = $node->source['input']->from;
                 if ($from && !isset($already[$from])) {
                     $already[$from] = true;
@@ -180,6 +197,9 @@ public function applyPrevMaps()
         }
     }
 
+    /**
+     * @return bool
+     */
     public function isAnnotation()
     {
         if ($this->isInline()) {
@@ -222,6 +242,9 @@ public function addAnnotation()
         $this->css .= $eol.'/*# sourceMappingURL='.$content.' */';
     }
 
+    /**
+     * @return string
+     */
     public function outputFile()
     {
         if (isset($this->opts['to']) && $this->opts['to']) {
@@ -233,6 +256,9 @@ public function outputFile()
         }
     }
 
+    /**
+     * @return array First array item is the css. If not inline, there's a second item (a SourceMap\Generator instance)
+     */
     public function generateMap()
     {
         $this->generateString();
@@ -254,9 +280,14 @@ public function generateMap()
         }
     }
 
+    /**
+     * @param string $file
+     *
+     * @return string
+     */
     public function relative($file)
     {
-        if (preg_match('/^\w+:\/\//', $file)) {
+        if ($file && ($file[0] === '<' || preg_match('/^\w+:\/\//', $file))) {
             return $file;
         }
 
@@ -274,7 +305,12 @@ public function relative($file)
         }
     }
 
-    public function sourcePath($node)
+    /**
+     * @param Node $node
+     *
+     * @return string
+     */
+    public function sourcePath(Node $node)
     {
         if (isset($this->mapOpts['from']) && $this->mapOpts['from']) {
             return $this->mapOpts['from'];
@@ -364,6 +400,9 @@ function ($str, Node $node = null, $type = null) use ($me, &$line, &$column) {
         );
     }
 
+    /**
+     * @return array First array item is the css. If not inline, there's a second item (a SourceMap\Generator instance)
+     */
     public function generate()
     {
         $this->clearAnnotation();
diff --git a/src/Node.php b/src/Node.php
index 9d6e043..c2cb6da 100644
--- a/src/Node.php
+++ b/src/Node.php
@@ -7,7 +7,7 @@
  *
  * @link https://github.com/postcss/postcss/blob/master/lib/node.es6
  */
-class Node
+abstract class Node
 {
     /**
      * Possible values are `root`, `atrule`, `rule`, `decl`, or `comment`.
@@ -17,7 +17,7 @@ class Node
     public $type = null;
 
     /**
-     * The node’s parent node.
+     * The node's parent node.
      *
      * @var Container|null
      */
@@ -43,15 +43,29 @@ class Node
      *   - `afterName`: the space between the at-rule name and its parameters.
      * - Comment:
      *   - `before`: the space symbols before the node.
-     *   - `left`: the space symbols between `/*` and the comment’s text.
-     *   - `right`: the space symbols between the comment’s text.
+     *   - `left`: the space symbols between `/*` and the comment's text.
+     *   - `right`: the space symbols between the comment's text.
+     * - Root:
+     *   - `after`: the space symbols after the last child to the end of file.
+     *   - `semicolon`: is the last child has an (optional) semicolon.
+     * - Rule:
+     *   - `before`: the space symbols before the node. It also stores `*` and `_` symbols before the declaration (IE hack).
+     *   - `after`: the space symbols after the last child of the node to the end of the node.
+     *   - `between`: the symbols between the property and value for declarations, selector and `{` for rules, or last parameter and `{` for at-rules.
+     *   - `semicolon`: contains true if the last child has an (optional) semicolon.
      *
      * PostCSS cleans at-rule parameters from comments and extra spaces, but it stores origin content in raws properties.
-     * As such, if you don’t change a declaration’s value, PostCSS will use the raw value with comments.
+     * As such, if you don't change a declaration's value, PostCSS will use the raw value with comments.
      *
      * @example
-     * $root = \PostCSS\Parser::parse('  @media\nprint {\n}')
+     * $root = \PostCSS\Parser::parse('  @media\nprint {\n}');
      * $root->first->first->raws //=> ['before' => '  ', 'between' => ' ', 'afterName' = > "\n", 'after' => "\n"]
+     * @example
+     * \PostCSS\Parser::parse('a {}\n').raws //=> ['after' => "\n"]
+     * \PostCSS\Parser::parse('a {}').raws   //=> ['after => '']
+     * @example
+     * $root = \PostCSS\Parser::parse('a {\n  color:black\n}');
+     * $root->first->first->raws //=> ['before' => '', 'between' => ' ', 'after' => "\n"]
      *
      * @var Raws
      */
diff --git a/src/Parser.php b/src/Parser.php
index 896ba2c..45d4918 100644
--- a/src/Parser.php
+++ b/src/Parser.php
@@ -12,26 +12,6 @@
  */
 class Parser
 {
-    const SINGLE_QUOTE = 0x27; //"'"
-    const DOUBLE_QUOTE = 0x22; //'"'
-    const BACKSLASH = 0x5c; //"\\"
-    const SLASH = 0x2f; //"/"
-    const NEWLINE = 0x0a; //"\n"
-    const SPACE = 0x20; //" "
-    const FEED = 0x0c; //"\f"
-    const TAB = 0x09; //"\t"
-    const CR = 0x0d; //"\r"
-    const OPEN_SQUARE = 0x5b; //"["
-    const CLOSE_SQUARE = 0x5d; //"]"
-    const OPEN_PARENTHESES = 0x28; //"("
-    const CLOSE_PARENTHESES = 0x29; //")"
-    const OPEN_CURLY = 0x7b; //"{"
-    const CLOSE_CURLY = 0x7d; //"}"
-    const SEMICOLON = 0x3b; //";"
-    const ASTERICK = 0x2a; //"*"
-    const COLON = 0x3a; //":"
-    const AT = 0x40; //"@"
-
     const RE_AT_END = '/[ \\n\\t\\r\\f\\{\\(\\)\'"\\\\;\\/\\[\\]#]/';
     const RE_WORD_END = '/[ \\n\\t\\r\\f\\(\\)\\{\\}:;@!\'"\\\\\\]\\[#]|\\/(?=\\*)/';
     const RE_BAD_BRACKET = '%.[\\\/\("\'\n]%';
@@ -535,60 +515,60 @@ public static function getTokens(Input $input, array $options = [])
         };
 
         while ($pos < $length) {
-            $code = ord($css[$pos]);
+            $code = $css[$pos];
 
-            if ($code === static::NEWLINE || $code === static::FEED || $code === static::CR && ($pos === $length - 1 || ord($css[$pos + 1]) !== static::NEWLINE)) {
+            if ($code === "\n" || $code === "\f" || $code === "\r" && ($pos === $length - 1 || $css[$pos + 1] !== "\n")) {
                 $offset = $pos;
                 $line += 1;
             }
 
             switch ($code) {
-                case static::NEWLINE:
-                case static::SPACE:
-                case static::TAB:
-                case static::CR:
-                case static::FEED:
+                case "\n":
+                case ' ':
+                case "\t":
+                case "\r":
+                case "\f":
                     $next = $pos;
                     do {
                         $next += 1;
-                        $code = ($next === $length) ? null : ord($css[$next]);
-                        if ($code === static::NEWLINE) {
+                        $code = ($next === $length) ? null : $css[$next];
+                        if ($code === "\n") {
                             $offset = $next;
                             $line += 1;
                         }
-                    } while ($code === static::SPACE || $code === static::NEWLINE || $code === static::TAB || $code === static::CR || $code === static::FEED);
+                    } while ($code === ' ' || $code === "\n" || $code === "\t" || $code === "\r" || $code === "\f");
                     $tokens[] = ['space', substr($css, $pos, $next - $pos)];
                     $pos = $next - 1;
                     break;
 
-                case static::OPEN_SQUARE:
+                case '[':
                     $tokens[] = ['[', '[', $line, $pos - $offset];
                     break;
 
-                case static::CLOSE_SQUARE:
+                case ']':
                     $tokens[] = [']', ']', $line, $pos - $offset];
                     break;
 
-                case static::OPEN_CURLY:
+                case '{':
                     $tokens[] = ['{', '{', $line, $pos - $offset];
                     break;
 
-                case static::CLOSE_CURLY:
+                case '}':
                     $tokens[] = ['}', '}', $line, $pos - $offset];
                     break;
 
-                case static::COLON:
+                case ':':
                     $tokens[] = [':', ':', $line, $pos - $offset];
                     break;
 
-                case static::SEMICOLON:
+                case ';':
                     $tokens[] = [';', ';', $line, $pos - $offset];
                     break;
 
-                case static::OPEN_PARENTHESES:
+                case '(':
                     $prev = empty($tokens) ? '' : $tokens[count($tokens) - 1][1];
-                    $n = ($pos < $length - 1) ? ord($css[$pos + 1]) : null;
-                    if ($prev === 'url' && $n !== static::SINGLE_QUOTE && $n !== static::DOUBLE_QUOTE && $n !== static::SPACE && $n !== static::NEWLINE && $n !== static::TAB && $n !== static::FEED && $n !== static::CR) {
+                    $n = ($pos < $length - 1) ? $css[$pos + 1] : null;
+                    if ($prev === 'url' && $n !== "'" && $n !== '"' && $n !== ' ' && $n !== "\n" && $n !== "\t" && $n !== "\f" && $n !== "\r") {
                         $next = $pos;
                         do {
                             $escaped = false;
@@ -602,7 +582,7 @@ public static function getTokens(Input $input, array $options = [])
                                 }
                             }
                             $escapePos = $next;
-                            while (ord($css[$escapePos - 1]) === static::BACKSLASH) {
+                            while ($css[$escapePos - 1] === '\\') {
                                 $escapePos -= 1;
                                 $escaped = !$escaped;
                             }
@@ -623,13 +603,13 @@ public static function getTokens(Input $input, array $options = [])
                     }
                     break;
 
-                    case static::CLOSE_PARENTHESES:
+                    case ')':
                         $tokens[] = [')', ')', $line, $pos - $offset];
                         break;
 
-                    case static::SINGLE_QUOTE:
-                    case static::DOUBLE_QUOTE:
-                        $quote = $code === static::SINGLE_QUOTE ? '\'' : '"';
+                    case "'":
+                    case '"':
+                        $quote = $code === "'" ? '\'' : '"';
                         $next = $pos;
                         do {
                             $escaped = false;
@@ -643,7 +623,7 @@ public static function getTokens(Input $input, array $options = [])
                                 }
                             }
                             $escapePos = $next;
-                            while (ord($css[$escapePos - 1]) === static::BACKSLASH) {
+                            while ($css[$escapePos - 1] === '\\') {
                                 $escapePos -= 1;
                                 $escaped = !$escaped;
                             }
@@ -668,7 +648,7 @@ public static function getTokens(Input $input, array $options = [])
                         $pos = $next;
                         break;
 
-                    case static::AT:
+                    case '@':
                         if (!preg_match(static::RE_AT_END, $css, $rxMatches, 0, $pos + 1)) {
                             $next = $length - 1;
                         } else {
@@ -678,15 +658,15 @@ public static function getTokens(Input $input, array $options = [])
                         $pos = $next;
                         break;
 
-                    case static::BACKSLASH:
+                    case '\\':
                         $next = $pos;
                         $escape = true;
-                        while (($next < ($length - 1)) && ord($css[$next + 1]) === static::BACKSLASH) {
+                        while (($next < ($length - 1)) && $css[$next + 1] === '\\') {
                             $next += 1;
                             $escape = !$escape;
                         }
-                        $code = ($next < ($length - 1)) ? ord($css[$next + 1]) : null;
-                        if ($escape && ($code !== static::SLASH && $code !== static::SPACE && $code !== static::NEWLINE && $code !== static::TAB && $code !== static::CR && $code !== static::FEED)) {
+                        $code = ($next < ($length - 1)) ? $css[$next + 1] : null;
+                        if ($escape && ($code !== '/' && $code !== ' ' && $code !== "\n" && $code !== "\t" && $code !== "\r" && $code !== "\f")) {
                             $next += 1;
                         }
                         $tokens[] = ['word', substr($css, $pos, $next + 1 - $pos), $line, $pos - $offset, $line, $next - $offset];
@@ -694,7 +674,7 @@ public static function getTokens(Input $input, array $options = [])
                         break;
 
                     default:
-                        if ($code === static::SLASH && $pos < ($length - 1) && ord($css[$pos + 1]) === static::ASTERICK) {
+                        if ($code === '/' && $pos < ($length - 1) && $css[$pos + 1] === '*') {
                             $next = strpos($css, '*/', $pos + 2);
                             if ($next === false) {
                                 if ($ignore) {
diff --git a/src/Path/NodeJS.php b/src/Path/NodeJS.php
index a84c366..03d32a8 100644
--- a/src/Path/NodeJS.php
+++ b/src/Path/NodeJS.php
@@ -59,7 +59,7 @@ protected static function posix_resolve(array $paths)
             }
 
             $resolvedPath = $path.'/'.$resolvedPath;
-            $resolvedAbsolute = ord($path[0]) === 47/*/*/;
+            $resolvedAbsolute = $path[0] === '/';
         }
         // At this point the path should be resolved to a full absolute path, but
         // handle relative paths to be safe (might happen when process.cwd() fails)
@@ -123,28 +123,28 @@ protected static function win32_resolve(array $paths)
             }
 
             $rootEnd = 0;
-            $code = ord($path[0]);
+            $code = $path[0];
             $device = '';
             $isAbsolute = false;
 
             // Try to match a root
             if ($len > 1) {
-                if ($code === 47/*/*/ || $code === 92/*\*/) {
+                if ($code === '/' || $code === '\\') {
                     // Possible UNC root
 
                     // If we started with a separator, we know we at least have an
                     // absolute path of some kind (UNC or otherwise)
                     $isAbsolute = true;
 
-                    $code = ord($path[1]);
-                    if ($code === 47/*/*/ || $code === 92/*\*/) {
+                    $code = $path[1];
+                    if ($code === '/' || $code === '\\') {
                         // Matched double path separator at beginning
                         $j = 2;
                         $last = $j;
                         // Match 1 or more non-path separators
                         for (; $j < $len; ++$j) {
-                            $code = ord($path[$j]);
-                            if ($code === 47/*/*/ || $code === 92/*\*/) {
+                            $code = $path[$j];
+                            if ($code === '/' || $code === '\\') {
                                 break;
                             }
                         }
@@ -154,8 +154,8 @@ protected static function win32_resolve(array $paths)
                             $last = $j;
                             // Match 1 or more path separators
                             for (; $j < $len; ++$j) {
-                                $code = ord($path[$j]);
-                                if ($code !== 47/*/*/ && $code !== 92/*\*/) {
+                                $code = $path[$j];
+                                if ($code !== '/' && $code !== '\\') {
                                     break;
                                 }
                             }
@@ -164,8 +164,8 @@ protected static function win32_resolve(array $paths)
                                 $last = $j;
                                 // Match 1 or more non-path separators
                                 for (; $j < $len; ++$j) {
-                                    $code = ord($path[$j]);
-                                    if ($code === 47/*/*/ || $code === 92/*\*/) {
+                                    $code = $path[$j];
+                                    if ($code === '/' || $code === '\\') {
                                         break;
                                     }
                                 }
@@ -183,15 +183,15 @@ protected static function win32_resolve(array $paths)
                     } else {
                         $rootEnd = 1;
                     }
-                } elseif (($code >= 65/*A*/ && $code <= 90/*Z*/) || ($code >= 97/*a*/ && $code <= 122/*z*/)) {
+                } elseif (($code >= 'A' && $code <= 'Z') || ($code >= 'a' && $code <= 'z')) {
                     // Possible device root
-                    $code = ord($path[1]);
-                    if ($code === 58/*:*/) {
+                    $code = $path[1];
+                    if ($code === ':') {
                         $device = substr($path, 0, 2);
                         $rootEnd = 2;
                         if ($len > 2) {
-                            $code = ord($path[2]);
-                            if ($code === 47/*/*/ || $code === 92/*\*/) {
+                            $code = $path[2];
+                            if ($code === '/' || $code === '\\') {
                                 // Treat separator following drive name as an absolute path
                                 // indicator
                                 $isAbsolute = true;
@@ -200,7 +200,7 @@ protected static function win32_resolve(array $paths)
                         }
                     }
                 }
-            } elseif ($code === 47/*/*/ || $code === 92/*\*/) {
+            } elseif ($code === '/' || $code === '\\') {
                 // `path` contains just a path separator
                 $rootEnd = 1;
                 $isAbsolute = true;
@@ -254,23 +254,23 @@ protected static function normalizeStringWin32($path, $allowAboveRoot)
         $pathLength = strlen($path);
         for ($i = 0; $i <= $pathLength; ++$i) {
             if ($i < $pathLength) {
-                $code = ord($path[$i]);
-            } elseif ($code === 47/*/*/ || $code === 92/*\*/) {
+                $code = $path[$i];
+            } elseif ($code === '/' || $code === '\\') {
                 break;
             } else {
-                $code = 47/*/*/;
+                $code = '/';
             }
-            if ($code === 47/*/*/ || $code === 92/*\*/) {
+            if ($code === '/' || $code === '\\') {
                 if ($lastSlash === $i - 1 || $dots === 1) {
                     // NOOP
                 } elseif ($lastSlash !== $i - 1 && $dots === 2) {
                     $resLength = strlen($res);
-                    if ($resLength < 2 || ord($res[$resLength - 1]) !== 46/*.*/ || ord($res[$resLength - 2]) !== 46/*.*/) {
+                    if ($resLength < 2 || $res[$resLength - 1] !== '.' || $res[$resLength - 2] !== '.') {
                         if ($resLength > 2) {
                             $start = $resLength - 1;
                             $j = $start;
                             for (; $j >= 0; --$j) {
-                                if (ord($res[$j]) === 92/*\*/) {
+                                if ($res[$j] === '\\') {
                                     break;
                                 }
                             }
@@ -307,7 +307,7 @@ protected static function normalizeStringWin32($path, $allowAboveRoot)
                 }
                 $lastSlash = $i;
                 $dots = 0;
-            } elseif ($code === 46/*.*/ && $dots !== -1) {
+            } elseif ($code === '.' && $dots !== -1) {
                 ++$dots;
             } else {
                 $dots = -1;
@@ -335,23 +335,23 @@ protected static function normalizeStringPosix($path, $allowAboveRoot)
         $pathLength = strlen($path);
         for ($i = 0; $i <= $pathLength; ++$i) {
             if ($i < $pathLength) {
-                $code = ord($path[$i]);
-            } elseif ($code === 47/*/*/) {
+                $code = $path[$i];
+            } elseif ($code === '/') {
                 break;
             } else {
-                $code = 47/*/*/;
+                $code = '/';
             }
-            if ($code === 47/*/*/) {
+            if ($code === '/') {
                 if ($lastSlash === $i - 1 || $dots === 1) {
                     // NOOP
                 } elseif ($lastSlash !== $i - 1 && $dots === 2) {
                     $resLength = strlen($res);
-                    if ($resLength < 2 || ord($res[$resLength - 1]) !== 46/*.*/ || ord($res[$resLength - 2]) !== 46/*.*/) {
+                    if ($resLength < 2 || $res[$resLength - 1] !== '.' || $res[$resLength - 2] !== '.') {
                         if ($resLength > 2) {
                             $start = $resLength - 1;
                             $j = $start;
                             for (; $j >= 0; --$j) {
-                                if (ord($res[$j]) === 47/*/*/) {
+                                if ($res[$j] === '/') {
                                     break;
                                 }
                             }
@@ -388,7 +388,7 @@ protected static function normalizeStringPosix($path, $allowAboveRoot)
                 }
                 $lastSlash = $i;
                 $dots = 0;
-            } elseif ($code === 46/*.*/ && $dots !== -1) {
+            } elseif ($code === '.' && $dots !== -1) {
                 ++$dots;
             } else {
                 $dots = -1;
@@ -455,14 +455,14 @@ protected static function win32_relative($from, $to)
         $fromStart = 0;
         $fl = strlen($from);
         for (; $fromStart < $fl; ++$fromStart) {
-            if (ord($from[$fromStart]) !== 92/*\*/) {
+            if ($from[$fromStart] !== '\\') {
                 break;
             }
         }
         // Trim trailing backslashes (applicable $to UNC paths only)
         $fromEnd = $fl;
         for (; $fromEnd - 1 > $fromStart; --$fromEnd) {
-            if (ord($from[$fromEnd - 1]) !== 92/*\*/) {
+            if ($from[$fromEnd - 1] !== '\\') {
                 break;
             }
         }
@@ -471,14 +471,14 @@ protected static function win32_relative($from, $to)
         $tl = strlen($to);
         $toStart = 0;
         for (; $toStart < $tl; ++$toStart) {
-            if (ord($to[$toStart]) !== 92/*\*/) {
+            if ($to[$toStart] !== '\\') {
                 break;
             }
         }
         // Trim trailing backslashes (applicable $to UNC paths only)
         $toEnd = $tl;
         for (; $toEnd - 1 > $toStart; --$toEnd) {
-            if (ord($to[$toEnd - 1]) !== 92/*\*/) {
+            if ($to[$toEnd - 1] !== '\\') {
                 break;
             }
         }
@@ -490,7 +490,7 @@ protected static function win32_relative($from, $to)
         for (; $i <= $length; ++$i) {
             if ($i === $length) {
                 if ($toLen > $length) {
-                    if (ord($to[$toStart + $i]) === 92/*\*/) {
+                    if ($to[$toStart + $i] === '\\') {
                         // We get here if `$from` is the exact base path for `$to`.
                         // For example: $from='C:\\foo\\bar'; $to='C:\\foo\\bar\\baz'
                         return substr($toOrig, $toStart + $i + 1);
@@ -501,7 +501,7 @@ protected static function win32_relative($from, $to)
                     }
                 }
                 if ($fromLen > $length) {
-                    if (ord($from[$fromStart + $i]) === 92/*\*/) {
+                    if ($from[$fromStart + $i] === '\\') {
                         // We get here if `$to` is the exact base path for `$from`.
                         // For example: $from='C:\\foo\\bar'; $to='C:\\foo'
                         $lastCommonSep = $i;
@@ -513,11 +513,11 @@ protected static function win32_relative($from, $to)
                 }
                 break;
             }
-            $fromCode = ord($from[$fromStart + $i]);
-            $toCode = ord($to[$toStart + $i]);
+            $fromCode = $from[$fromStart + $i];
+            $toCode = $to[$toStart + $i];
             if ($fromCode !== $toCode) {
                 break;
-            } elseif ($fromCode === 92/*\*/) {
+            } elseif ($fromCode === '\\') {
                 $lastCommonSep = $i;
             }
         }
@@ -537,7 +537,7 @@ protected static function win32_relative($from, $to)
         }
         // Generate the relative path based on the path difference between `$to` and `$from`
         for ($i = $fromStart + $lastCommonSep + 1; $i <= $fromEnd; ++$i) {
-            if ($i === $fromEnd || ord($from[$i]) === 92/*\*/) {
+            if ($i === $fromEnd || $from[$i] === '\\') {
                 if ($out === '') {
                     $out = '..';
                 } else {
@@ -551,7 +551,7 @@ protected static function win32_relative($from, $to)
             return $out.substr($toOrig, $toStart + $lastCommonSep, $toEnd - $toStart + $lastCommonSep);
         } else {
             $toStart .= $lastCommonSep;
-            if (ord($toOrig[$toStart]) === 92/*\*/) {
+            if ($toOrig[$toStart] === '\\') {
                 ++$toStart;
             }
 
@@ -589,7 +589,7 @@ protected static function posix_relative($from, $to)
         $fromStart = 1;
         $fl = strlen($from);
         for (; $fromStart < $fl; ++$fromStart) {
-            if (ord($from[$fromStart]) !== 47/*/*/) {
+            if ($from[$fromStart] !== '/') {
                 break;
             }
         }
@@ -599,7 +599,7 @@ protected static function posix_relative($from, $to)
         $toStart = 1;
         $tl = strlen($to);
         for (; $toStart < $tl; ++$toStart) {
-            if (ord($to[$toStart]) !== 47/*/*/) {
+            if ($to[$toStart] !== '/') {
                 break;
             }
         }
@@ -612,7 +612,7 @@ protected static function posix_relative($from, $to)
         for (; $i <= $length; ++$i) {
             if ($i === $length) {
                 if ($toLen > $length) {
-                    if (ord($to[$toStart + $i]) === 47/*/*/) {
+                    if ($to[$toStart + $i] === '/') {
                         // We get here if `$from` is the exact base path for `$to`.
                         // For example: $from='/foo/bar'; $to='/foo/bar/baz'
                         return substr($to, $toStart + $i + 1);
@@ -622,7 +622,7 @@ protected static function posix_relative($from, $to)
                         return substr($to, $toStart + $i);
                     }
                 } elseif ($fromLen > $length) {
-                    if (ord($from[$fromStart + $i]) === 47/*/*/) {
+                    if ($from[$fromStart + $i] === '/') {
                         // We get here if `$to` is the exact base path for `$from`.
                         // For example: $from='/foo/bar/baz'; $to='/foo/bar'
                         $lastCommonSep = $i;
@@ -634,18 +634,18 @@ protected static function posix_relative($from, $to)
                 }
                 break;
             }
-            $fromCode = ord($from[$fromStart + $i]);
-            $toCode = ord($to[$toStart + $i]);
+            $fromCode = $from[$fromStart + $i];
+            $toCode = $to[$toStart + $i];
             if ($fromCode !== $toCode) {
                 break;
-            } elseif ($fromCode === 47/*/*/) {
+            } elseif ($fromCode === '/') {
                 $lastCommonSep = $i;
             }
         }
         $out = '';
         // Generate the relative path based on the path difference between `$to` and `$from`
         for ($i = $fromStart + $lastCommonSep + 1; $i <= $fromEnd; ++$i) {
-            if ($i === $fromEnd || ord($from[$i]) === 47/*/*/) {
+            if ($i === $fromEnd || $from[$i] === '/') {
                 if ($out === '') {
                     $out = '..';
                 } else {
@@ -658,7 +658,7 @@ protected static function posix_relative($from, $to)
             return $out.substr($to, $toStart + $lastCommonSep);
         } else {
             $toStart += $lastCommonSep;
-            if (ord($to[$toStart]) === 47/*/*/) {
+            if ($to[$toStart] === '/') {
                 ++$toStart;
             }
 
@@ -706,22 +706,22 @@ protected static function win32_dirname($path)
         $end = -1;
         $matchedSlash = true;
         $offset = 0;
-        $code = ord($path[0]);
+        $code = $path[0];
 
         // Try to match a root
         if ($len > 1) {
-            if ($code === 47/*/*/ || $code === 92/*\*/) {
+            if ($code === '/' || $code === '\\') {
                 // Possible UNC root
                 $rootEnd = $offset = 1;
-                $code = ord($path[1]);
-                if ($code === 47/*/*/ || $code === 92/*\*/) {
+                $code = $path[1];
+                if ($code === '/' || $code === '\\') {
                     // Matched double path separator at beginning
                     $j = 2;
                     $last = $j;
                     // Match 1 or more non-path separators
                     for (; $j < $len; ++$j) {
-                        $code = ord($path[$j]);
-                        if ($code === 47/*/*/ || $code === 92/*\*/) {
+                        $code = $path[$j];
+                        if ($code === '/' || $code === '\\') {
                             break;
                         }
                     }
@@ -730,8 +730,8 @@ protected static function win32_dirname($path)
                         $last = $j;
                         // Match 1 or more path separators
                         for (; $j < $len; ++$j) {
-                            $code = ord($path[$j]);
-                            if ($code !== 47/*/*/ && $code !== 92/*\*/) {
+                            $code = $path[$j];
+                            if ($code !== '/' && $code !== '\\') {
                                 break;
                             }
                         }
@@ -740,8 +740,8 @@ protected static function win32_dirname($path)
                             $last = $j;
                             // Match 1 or more non-path separators
                             for (; $j < $len; ++$j) {
-                                $code = ord($path[$j]);
-                                if ($code === 47/*/*/ || $code === 92/*\*/) {
+                                $code = $path[$j];
+                                if ($code === '/' || $code === '\\') {
                                     break;
                                 }
                             }
@@ -758,26 +758,26 @@ protected static function win32_dirname($path)
                         }
                     }
                 }
-            } elseif (($code >= 65/*A*/ && $code <= 90/*Z*/) || ($code >= 97/*a*/ && $code <= 122/*z*/)) {
+            } elseif (($code >= 'A' && $code <= 'Z') || ($code >= 'a' && $code <= 'z')) {
                 // Possible device root
-                $code = ord($path[1]);
-                if (ord($path[1]) === 58/*:*/) {
+                $code = $path[1];
+                if ($path[1] === ':') {
                     $rootEnd = $offset = 2;
                     if ($len > 2) {
-                        $code = ord($path[2]);
-                        if ($code === 47/*/*/ || $code === 92/*\*/) {
+                        $code = $path[2];
+                        if ($code === '/' || $code === '\\') {
                             $rootEnd = $offset = 3;
                         }
                     }
                 }
             }
-        } elseif ($code === 47/*/*/ || $code === 92/*\*/) {
+        } elseif ($code === '/' || $code === '\\') {
             return $path[0];
         }
 
         for ($i = $len - 1; $i >= $offset; --$i) {
-            $code = ord($path[$i]);
-            if ($code === 47/*/*/ || $code === 92/*\*/) {
+            $code = $path[$i];
+            if ($code === '/' || $code === '\\') {
                 if (!$matchedSlash) {
                     $end = $i;
                     break;
@@ -817,13 +817,13 @@ protected static function posix_dirname($path)
         if ($len === 0) {
             return '.';
         }
-        $code = ord($path[0]);
-        $hasRoot = ($code === 47/*/*/);
+        $code = $path[0];
+        $hasRoot = ($code === '/');
         $end = -1;
         $matchedSlash = true;
         for ($i = $len - 1; $i >= 1; --$i) {
-            $code = ord($path[$i]);
-            if ($code === 47/*/*/) {
+            $code = $path[$i];
+            if ($code === '/') {
                 if (!$matchedSlash) {
                     $end = $i;
                     break;
@@ -894,17 +894,17 @@ protected static function win32_join(array $arguments)
         // var firstPart = paths[0];
         $needsReplace = true;
         $slashCount = 0;
-        $code = ord($firstPart[0]);
-        if ($code === 47/*/*/ || $code === 92/*\*/) {
+        $code = $firstPart[0];
+        if ($code === '/' || $code === '\\') {
             ++$slashCount;
             $firstLen = strlen($firstPart);
             if ($firstLen > 1) {
-                $code = ord($firstPart[1]);
-                if ($code === 47/*/*/ || $code === 92/*\*/) {
+                $code = $firstPart[1];
+                if ($code === '/' || $code === '\\') {
                     ++$slashCount;
                     if ($firstLen > 2) {
-                        $code = ord($firstPart[2]);
-                        if ($code === 47/*/*/ || $code === 92/*\*/) {
+                        $code = $firstPart[2];
+                        if ($code === '/' || $code === '\\') {
                             ++$slashCount;
                         } else {
                             // We matched a UNC path in the first part
@@ -917,8 +917,8 @@ protected static function win32_join(array $arguments)
         if ($needsReplace) {
             // Find any more consecutive slashes we need to replace
             for (; $slashCount < strlen($joined); ++$slashCount) {
-                $code = ord($joined[$slashCount]);
-                if ($code !== 47/*/*/ && $code !== 92/*\*/) {
+                $code = $joined[$slashCount];
+                if ($code !== '/' && $code !== '\\') {
                     break;
                 }
             }
@@ -999,26 +999,26 @@ protected static function win32_normalize($path)
             return '.';
         }
         $rootEnd = 0;
-        $code = ord($path[0]);
+        $code = $path[0];
         $device = null;
         $isAbsolute = false;
         // Try to match a root
         if ($len > 1) {
-            if ($code === 47/*/*/ || $code === 92/*\*/) {
+            if ($code === '/' || $code === '\\') {
                 // Possible UNC root
 
                 // If we started with a separator, we know we at least have an absolute path of some kind (UNC or otherwise)
                 $isAbsolute = true;
 
-                $code = ord($path[1]);
-                if ($code === 47/*/*/ || $code === 92/*\*/) {
+                $code = $path[1];
+                if ($code === '/' || $code === '\\') {
                     // Matched double path separator at beginning
                     $j = 2;
                     $last = $j;
                     // Match 1 or more non-path separators
                     for (; $j < $len; ++$j) {
-                        $code = ord($path[$j]);
-                        if ($code === 47/*/*/ || $code === 92/*\*/) {
+                        $code = $path[$j];
+                        if ($code === '/' || $code === '\\') {
                             break;
                         }
                     }
@@ -1028,8 +1028,8 @@ protected static function win32_normalize($path)
                         $last = $j;
                         // Match 1 or more path separators
                         for (; $j < $len; ++$j) {
-                            $code = ord($path[$j]);
-                            if ($code !== 47/*/*/ && $code !== 92/*\*/) {
+                            $code = $path[$j];
+                            if ($code !== '/' && $code !== '\\') {
                                 break;
                             }
                         }
@@ -1038,8 +1038,8 @@ protected static function win32_normalize($path)
                             $last = $j;
                             // Match 1 or more non-path separators
                             for (; $j < $len; ++$j) {
-                                $code = ord($path[$j]);
-                                if ($code === 47/*/*/ || $code === 92/*\*/) {
+                                $code = $path[$j];
+                                if ($code === '/' || $code === '\\') {
                                     break;
                                 }
                             }
@@ -1059,16 +1059,16 @@ protected static function win32_normalize($path)
                 } else {
                     $rootEnd = 1;
                 }
-            } elseif (($code >= 65/*A*/ && $code <= 90/*Z*/) || ($code >= 97/*a*/ && $code <= 122/*z*/)) {
+            } elseif (($code >= 'A' && $code <= 'Z') || ($code >= 'a' && $code <= 'z')) {
                 // Possible device root
 
-                $code = ord($path[1]);
-                if (ord($path[1]) === 58/*:*/) {
+                $code = $path[1];
+                if ($path[1] === ':') {
                     $device = substr($path, 0, 2);
                     $rootEnd = 2;
                     if ($len > 2) {
-                        $code = ord($path[2]);
-                        if ($code === 47/*/*/ || $code === 92/*\*/) {
+                        $code = $path[2];
+                        if ($code === '/' || $code === '\\') {
                             // Treat separator following drive name as an absolute path indicator
                             $isAbsolute = true;
                             $rootEnd = 3;
@@ -1076,13 +1076,13 @@ protected static function win32_normalize($path)
                     }
                 }
             }
-        } elseif ($code === 47/*/*/ || $code === 92/*\*/) {
+        } elseif ($code === '/' || $code === '\\') {
             // `path` contains just a path separator, exit early to avoid unnecessary work
             return '\\';
         }
 
-        $code = ord($path[$len - 1]);
-        $trailingSeparator = ($code === 47/*/*/ || $code === 92/*\*/);
+        $code = $path[$len - 1];
+        $trailingSeparator = ($code === '/' || $code === '\\');
         if ($rootEnd < $len) {
             $tail = static::normalizeStringWin32(substr($path, $rootEnd), !$isAbsolute);
         } else {
@@ -1138,8 +1138,8 @@ protected static function posix_normalize($path)
         if ($path === '') {
             return '.';
         }
-        $isAbsolute = ord($path[0]) === 47/*/*/;
-        $trailingSeparator = ord($path[strlen($path) - 1]) === 47/*/*/;
+        $isAbsolute = $path[0] === '/';
+        $trailingSeparator = $path[strlen($path) - 1] === '/';
 
         // Normalize the path
         $path = static::normalizeStringPosix($path, !$isAbsolute);
diff --git a/src/PreviousMap.php b/src/PreviousMap.php
index 41a5ea3..c7c2ed7 100644
--- a/src/PreviousMap.php
+++ b/src/PreviousMap.php
@@ -2,9 +2,9 @@
 
 namespace PostCSS;
 
-use PostCSS\SourceMap\Consumer\Consumer as MozillaSourceMapConsumer;
-use PostCSS\SourceMap\Generator as MozillaSourceMapGenerator;
 use PostCSS\Path\NodeJS as Path;
+use PostCSS\SourceMap\Consumer\Consumer as SourceMapConsumer;
+use PostCSS\SourceMap\Generator as SourceMapGenerator;
 
 /**
  * Source map information from input CSS.
@@ -13,6 +13,10 @@
  * This class will automatically find source map in input CSS or in file system near input file (according `from` option).
  *
  * @link https://github.com/postcss/postcss/blob/master/lib/previous-map.es6
+ *
+ * @example
+ * $root = \PostCSS\Parser::parse($css, ['from' => 'a.sass.css']);
+ * $root->input->map //=> PreviousMap
  */
 class PreviousMap
 {
@@ -22,6 +26,8 @@ class PreviousMap
     public $annotation = '';
 
     /**
+     * Was source map inlined by data-uri to input CSS.
+     *
      * @var bool
      */
     public $inline;
@@ -32,13 +38,13 @@ class PreviousMap
     public $text = null;
 
     /**
-     * @var MozillaSourceMapConsumer|null
+     * @var SourceMapConsumer|null
      */
     private $consumerCache = null;
 
     /**
      * @param string $css Input CSS source
-     * @param processOptions $opts {@link Processor#process} options
+     * @param array $opts Options
      */
     public function __construct($css, array $opts)
     {
@@ -56,12 +62,12 @@ public function __construct($css, array $opts)
      *
      * It is lazy method, so it will create object only on first call and then it will use cache.
      *
-     * @return MozillaSourceMapConsumer object woth source map information
+     * @return SourceMapConsumer object with source map information
      */
     public function consumer()
     {
         if ($this->consumerCache === null) {
-            $this->consumerCache = MozillaSourceMapConsumer::construct($this->text);
+            $this->consumerCache = SourceMapConsumer::construct($this->text);
         }
 
         return $this->consumerCache;
@@ -70,7 +76,7 @@ public function consumer()
     /**
      * Does source map contains `sourcesContent` with input source text.
      *
-     * @return {boolean} Is `sourcesContent` present
+     * @return bool Is `sourcesContent` present
      */
     public function withContent()
     {
@@ -79,11 +85,20 @@ public function withContent()
         return !empty($sc);
     }
 
+    /**
+     * @param string $string
+     * @param string $start
+     *
+     * @return bool
+     */
     public function startWith($string, $start)
     {
         return is_string($string) && $string !== '' && substr($string, 0, strlen($start)) === $start;
     }
 
+    /**
+     * @param string $css
+     */
     public function loadAnnotation($css)
     {
         if (preg_match('/\/\*\s*# sourceMappingURL=(.*)\s*\*\//', $css, $match)) {
@@ -91,6 +106,13 @@ public function loadAnnotation($css)
         }
     }
 
+    /**
+     * @param string $text
+     *
+     * @throws Exception\UnsupportedSourceMapEncoding
+     *
+     * @return string
+     */
     public function decodeInline($text)
     {
         $utfd64 = 'data:application/json;charset=utf-8;base64,';
@@ -116,6 +138,15 @@ public function decodeInline($text)
         }
     }
 
+    /**
+     * @param string $file
+     * @param mixed $prev
+     *
+     * @throws Exception\UnableToLoadPreviousSourceMap
+     * @throws Exception\UnsupportedPreviousSourceMapFormat
+     *
+     * @return string|false
+     */
     public function loadMap($file, $prev)
     {
         if ($prev === false) {
@@ -132,9 +163,9 @@ public function loadMap($file, $prev)
                 } else {
                     throw new Exception\UnableToLoadPreviousSourceMap($prevPath);
                 }
-            } elseif ($prev instanceof MozillaSourceMapConsumer) {
-                return (string) MozillaSourceMapGenerator::fromSourceMap($prev);
-            } elseif ($prev instanceof MozillaSourceMapGenerator) {
+            } elseif ($prev instanceof SourceMapConsumer) {
+                return (string) SourceMapGenerator::fromSourceMap($prev);
+            } elseif ($prev instanceof SourceMapGenerator) {
                 return (string) $prev;
             } elseif ($this->isMap($prev)) {
                 return json_encode($prev);
@@ -157,6 +188,11 @@ public function loadMap($file, $prev)
         }
     }
 
+    /**
+     * @param array|mixed $map
+     *
+     * @return bool
+     */
     public function isMap($map)
     {
         $result = false;
diff --git a/src/Processor.php b/src/Processor.php
index 739d1d4..3264157 100644
--- a/src/Processor.php
+++ b/src/Processor.php
@@ -9,6 +9,11 @@
  *
  * @link https://github.com/postcss/postcss/blob/master/lib/processor.es6
  * @link https://github.com/postcss/postcss/blob/master/lib/postcss.es6
+ *
+ * @example
+ * $processor = new \PostCSS\Processor([Autoprefixer::class, Precss::class]);
+ * $processor->process($css1)->then(function ($result) { echo $result->css; })->done();
+ * $processor->process($css2)->then(function ($result) { echo $result->css; })->done();
  */
 class Processor
 {
@@ -25,7 +30,7 @@ class Processor
     public $plugins;
 
     /**
-     * @param PluginInterface[]|callable[]|Processor[]} $plugins PostCSS plugins
+     * @param PluginInterface[]|callable[]|Processor[]} $plugins PostCSS plugins. Processor->usePlugin for plugin format
      */
     public function __construct($plugins = [])
     {
@@ -40,31 +45,24 @@ public function __construct($plugins = [])
     /**
      * Adds a plugin to be used as a CSS processor.
      *
-     * PostCSS plugin can be in 4 formats:
-     * * A plugin created by {@link postcss.plugin} method.
-     * * A function. PostCSS will pass the function a {@link Root}
-     *   as the first argument and current {@link Result} instance
-     *   as the second.
-     * * An object with a `postcss` method. PostCSS will use that method
-     *   as described in #2.
-     * * Another {@link Processor} instance. PostCSS will copy plugins
-     *   from that instance into this one.
+     * PostCSS plugin can be in the following formats:
+     * - An \PostCSS\PluginInterface instance.
+     * - The name of a \PostCSS\PluginInterface class.
+     * - A callable that returns a \PostCSS\PluginInterface instance.
+     * - Another Processor} instance. PostCSS will copy plugins from that instance into this one.
      *
-     * Plugins can also be added by passing them as arguments when creating
-     * a `postcss` instance (see [`postcss(plugins)`]).
+     * Plugins can also be added by passing them as arguments when creating \PostCSS\Processor instance.
      *
      * Asynchronous plugins should return a `\React\Promise\Promise` instance.
      *
-     * @param {Plugin|pluginFunction|Processor} plugin - PostCSS plugin
-     *                                                   or {@link Processor}
-     *                                                   with plugins
+     * @param PluginInterface|string|callable|Processor $plugin PostCSS plugin Processor with plugins
      *
      * @example
-     * const processor = postcss()
-     *   .use(autoprefixer)
-     *   .use(precss);
+     * $processor = (new \PostCSS\Processor())
+     *     ->usePlugin(Autoprefixer::class)
+     *     ->usePlugin(Precss::class);
      *
-     * @return {Processes} current processor to make methods chain
+     * @return static Current processor to make methods chain
      */
     public function usePlugin($plugin)
     {
@@ -74,26 +72,17 @@ public function usePlugin($plugin)
     }
 
     /**
-     * Parses source CSS and returns a {@link LazyResult} Promise proxy.
-     * Because some plugins can be asynchronous it doesn't make
-     * any transformations. Transformations will be applied
-     * in the {@link LazyResult} methods.
+     * Parses source CSS and returns a LazyResult Promise proxy.
+     * Because some plugins can be asynchronous it doesn't make any transformations.
+     * Transformations will be applied in the LazyResult methods.
      *
-     * @param {string|toString|Result} css - String with input CSS or
-     *                                       any object with a `toString()`
-     *                                       method, like a Buffer.
-     *                                       Optionally, send a {@link Result}
-     *                                       instance and the processor will
-     *                                       take the {@link Root} from it
-     * @param {processOptions} [opts]      - options
+     * @param string|Root|Result|LazyResult $css String with input CSS or any object with a `__toString()` method. Optionally, send a Result instance and the processor will take the Root from it
+     * @param array $opts] Options
      *
      * @return LazyResult \React\Promise\Promise proxy
      *
      * @example
-     * processor.process(css, { from: 'a.css', to: 'a.out.css' })
-     *   .then(result => {
-     *      console.log(result.css);
-     *   });
+     * $processor->process($css, ['from' => 'a.css', 'to' => 'a.out.css'])->then(function ($result) { echo $result->css; })->done();
      */
     public function process($css, array $opts = [])
     {
diff --git a/src/Result.php b/src/Result.php
index a1dd053..a571c69 100644
--- a/src/Result.php
+++ b/src/Result.php
@@ -6,48 +6,76 @@
 
 /**
  * Provides the result of the PostCSS transformations.
- * A Result instance is returned by {@link LazyResult#then} or {@link Root#toResult} methods.
+ * A Result instance is returned by LazyResult->then or Root->toResult methods.
  *
  * @link https://github.com/postcss/postcss/blob/master/lib/result.es6
  *
  * @example
- * postcss([cssnext]).process(css).then(function (result) {
- *    console.log(result.css);
+ * (new \PostCSS\Processor([cssnext]))->process($css)->then(function ($result) {
+ *    echo $result->css;
  * });
  * @example
- * var result2 = postcss.parse(css).toResult();
+ * $result2 = \PostCSS\Parser::parse($css).toResult();
  *
  * @property string $content An alias for the Result->css property. Use it with syntaxes that generate non-CSS output
  */
 class Result
 {
     /**
+     * The Processor instance used for this transformation.
+     *
      * @var Processor
      */
     public $processor;
 
     /**
+     * Contains messages from plugins (e.g., warnings or custom messages). Each message should have type and plugin properties.
+     *
      * @var array
      */
     public $messages;
 
     /**
+     * Root node after all transformations.
+     *
+     * @example
+     * $root->toResult()->root === root;
+     *
      * @var Root|null
      */
     public $root;
 
     /**
+     * Options from the Processor->process or Root->toResult} call that produced this Result instance.
+     *
+     * @example
+     * $root->toResult($opts)->opts == $opts;
+     *
      * @var array
      */
     public $opts;
 
     /**
-     * @var string|null A CSS string representing of {@link Result#root}
+     * A CSS string representing of Result->root.
+     *
+     * @example
+     * \PostCSS\Parser::parse('a{}')->toResult()->css //=> 'a{}'
+     *
+     * @var string|null
      */
     public $css;
 
     /**
-     * @var SourceMap\Generator|null An instance of `SourceMapGenerator` class from the `source-map` library, representing changes o the {@link Result#root} instance
+     * An instance of `SourceMapGenerator` class from the `source-map` library, representing changes o the Result->root instance.
+     *
+     * @example
+     * $result->map->toJSON() //=> ['version' => 3, 'file' => 'a.css', ...]
+     * @example
+     * if ($result->map) {
+     *     file_put_contents($result->opts['to'].'.map', (string) $result->map);
+     * }
+     *
+     * @var SourceMap\Generator|null
      */
     public $map;
 
@@ -57,10 +85,9 @@ class Result
     public $lastPlugin = null;
 
     /**
-     * @param {Processor} processor - processor used for this transformation
-     * @param {Root}      root      - Root node after all transformations
-     * @param {processOptions} opts - options from the {@link Processor#process}
-     *                                or {@link Root#toResult}
+     * @param Processor $processor Processor used for this transformation
+     * @param Root $root Root node after all transformations
+     * @param array $opts Options from the Processor->process or Root->toResult
      */
     public function __construct(Processor $processor = null, Root $root = null, array $opts = [])
     {
@@ -73,9 +100,9 @@ public function __construct(Processor $processor = null, Root $root = null, arra
     }
 
     /**
-     * Returns for {@link Result#css} content.
+     * Returns for Result->css content.
      *
-     * @return string string representing of {@link Result#root}
+     * @return string string representing of Result->root
      */
     public function __toString()
     {
@@ -83,14 +110,16 @@ public function __toString()
     }
 
     /**
-     * Creates an instance of {@link Warning} and adds it to {@link Result#messages}.
+     * Creates an instance of {@link Warning} and adds it to Result->messages.
+     *
+     * @param string $text Warning message
+     * @param array $opts Warning options {
      *
-     * @param string $text - warning message
-     * @param array  $opts - warning options
-     * @param Node   opts.node   - CSS node that caused the warning
-     * @param string opts.word   - word in CSS source that caused the warning
-     * @param int opts.index  - index in CSS node string that caused the warning
-     * @param string opts.plugin - name of the plugin that created this warning. {@link Result#warn} fills this property automatically
+     *     @var Node $node CSS node that caused the warning
+     *     @var string $word Word in CSS source that caused the warning
+     *     @var int $index Index in CSS node string that caused the warning
+     *     @var string $plugin Name of the plugin that created this warning. Result->warn fills this property automatically.
+     * }
      *
      * @return Warning created warning
      */
@@ -109,9 +138,14 @@ public function warn($text, array $opts = [])
     }
 
     /**
-     * Returns warnings from plugins. Filters {@link Warning} instances from {@link Result#messages}.
+     * Returns warnings from plugins. Filters Warning instances from Result->messages.
+     *
+     * @example
+     * foreach ($result->warnings() as warn) {
+     *     echo (string) $warn;
+     * }
      *
-     * @return {Warning[]} warnings from plugins
+     * @return Warning[] warnings from plugins
      */
     public function warnings()
     {
diff --git a/src/Root.php b/src/Root.php
index 0daf821..1729fcb 100644
--- a/src/Root.php
+++ b/src/Root.php
@@ -6,9 +6,17 @@
  * Represents a CSS file and contains all its parsed nodes.
  *
  * @link https://github.com/postcss/postcss/blob/master/lib/root.es6
+ *
+ * @example
+ * $root = \PostCSS\Parser::parse('a{color:black} b{z-index:2}');
+ * $root->type         //=> 'root'
+ * count($root->nodes) //=> 2
  */
 class Root extends Container
 {
+    /**
+     * @param array $defaults
+     */
     public function __construct(array $defaults = [])
     {
         parent::__construct($defaults);
@@ -18,6 +26,11 @@ public function __construct(array $defaults = [])
         }
     }
 
+    /**
+     * {@inheritdoc}
+     *
+     * @see Container::removeChild()
+     */
     public function removeChild($child)
     {
         $child = $this->index($child);
@@ -34,6 +47,11 @@ public function removeChild($child)
         return parent::removeChild($child);
     }
 
+    /**
+     * {@inheritdoc}
+     *
+     * @see Container::normalize()
+     */
     public function normalize($child, $sample = null, $type = null)
     {
         $nodes = parent::normalize($child);
@@ -65,9 +83,9 @@ public function normalize($child, $sample = null, $type = null)
     }
 
     /**
-     * Returns a {@link Result} instance representing the root's CSS.
+     * Returns a Result instance representing the root's CSS.
      *
-     * @param ProcessOptions $opts Options with only `to` and `map` keys
+     * @param array $opts Options with only `to` and `map` keys. Same values as LazyResult::__constructor
      *
      * @return Result Result with current root's CSS
      */
@@ -79,7 +97,7 @@ public function toResult(array $opts = [])
     }
 
     /**
-     * @deprecated Use Root#removeChild
+     * @deprecated Use Root->removeChild
      */
     public function remove()
     {
@@ -92,7 +110,7 @@ public function remove()
     }
 
     /**
-     * @deprecated Use Root#source->input->map
+     * @deprecated Use Root->source->input->map
      */
     public function prevMap()
     {
diff --git a/src/Rule.php b/src/Rule.php
index c5ce5c9..bc8f16e 100644
--- a/src/Rule.php
+++ b/src/Rule.php
@@ -6,14 +6,28 @@
  * Represents a CSS rule: a selector followed by a declaration block.
  *
  * @link https://github.com/postcss/postcss/blob/master/lib/rule.es6
+ *
+ * @example
+ * $root = \PostCSS\Parser::parse('a{}');
+ * $rule = $root->first;
+ * $rule->type    //=> 'rule'
+ * (string) $rule //=> 'a{}'
+ *
+ * @property string[] $selectors An array containing the rule's individual selectors. Groups of selectors are split at commas
+ * @property @deprecated string $_selector Rule->_selector is deprecated. Use Rule->raws->selector
  */
 class Rule extends Container
 {
     /**
+     * The rule's full selector represented as a string.
+     *
      * @var string|null
      */
     public $selector = null;
 
+    /**
+     * @param array $defaults
+     */
     public function __construct(array $defaults = [])
     {
         $selectors = null;
@@ -27,41 +41,38 @@ public function __construct(array $defaults = [])
             $this->nodes = [];
         }
         if ($selectors !== null) {
-            $this->setSelectors($selectors);
+            $this->selectors = $selectors;
         }
     }
 
-    /**
-     * An array containing the rule's individual selectors.
-     * Groups of selectors are split at commas.
-     */
-    public function getSelectors()
-    {
-        return ListUtil::comma($this->selector);
-    }
-
-    public function setSelectors(array $values)
+    public function __get($name)
     {
-        if (!isset($this->selector) || !$this->selector || !preg_match('/,\s*/', $this->selector, $match)) {
-            $match = null;
+        switch ($name) {
+            case 'selectors':
+                return ListUtil::comma($this->selector);
+            case '_selector':
+                return $this->raws->selector;
+            default:
+                return parent::__get($name);
         }
-        $sep = ($match !== null) ? $match[0] : ','.$this->raw('between', 'beforeOpen');
-        $this->selector = implode($sep, $values);
     }
 
-    /**
-     * @deprecated Rule#_selector is deprecated. Use Rule#raws.selector
-     */
-    public function _getSelector()
-    {
-        return $this->raws->selector;
-    }
-
-    /**
-     * @deprecated Rule#_selector is deprecated. Use Rule#raws.selector
-     */
-    public function _setSelector($val)
+    public function __set($name, $value)
     {
-        $this->raws->selector = $val;
+        switch ($name) {
+            case 'selectors':
+                if (!$this->selector || !preg_match('/,\s*/', $this->selector, $match)) {
+                    $match = null;
+                }
+                $sep = ($match !== null) ? $match[0] : ','.$this->raw('between', 'beforeOpen');
+                $this->selector = implode($sep, (array) $value);
+                break;
+            case '_selector':
+                $this->raws->selector = $value;
+                break;
+            default:
+                parent::__set($name, $value);
+                break;
+        }
     }
 }
diff --git a/src/Stringifier.php b/src/Stringifier.php
index fdf9c70..3435d60 100644
--- a/src/Stringifier.php
+++ b/src/Stringifier.php
@@ -32,6 +32,11 @@ class Stringifier
         'commentRight' => ' ',
     ];
 
+    /**
+     * @param string $str
+     *
+     * @return string
+     */
     protected static function capitalize($str)
     {
         $str = (string) $str;
@@ -46,12 +51,20 @@ protected static function capitalize($str)
         return $str;
     }
 
+    /**
+     * @param callable|null $builder
+     * @param callable|null $stringifier
+     */
     public function __construct(callable $builder = null, callable $stringifier = null)
     {
         $this->builder = $builder;
         $this->stringifier = $stringifier;
     }
 
+    /**
+     * @param Node $node
+     * @param bool $semicolon
+     */
     public function stringify(Node $node, $semicolon = null)
     {
         if ($this->stringifier !== null) {
@@ -63,6 +76,9 @@ public function stringify(Node $node, $semicolon = null)
         }
     }
 
+    /**
+     * @param Node $node
+     */
     protected function root(Node $node)
     {
         $this->body($node);
@@ -72,6 +88,9 @@ protected function root(Node $node)
         }
     }
 
+    /**
+     * @param Node $node
+     */
     protected function comment(Node $node)
     {
         $left = $this->raw($node, 'left', 'commentLeft');
@@ -79,6 +98,10 @@ protected function comment(Node $node)
         call_user_func($this->builder, '/*'.$left.$node->text.$right.'*/', $node);
     }
 
+    /**
+     * @param Node $node
+     * @param bool $semicolon
+     */
     protected function decl(Node $node, $semicolon)
     {
         $between = $this->raw($node, 'between', 'colon');
@@ -92,11 +115,18 @@ protected function decl(Node $node, $semicolon)
         call_user_func($this->builder, $string, $node);
     }
 
+    /**
+     * @param Node $node
+     */
     protected function rule(Node $node)
     {
         $this->block($node, $this->rawValue($node, 'selector'));
     }
 
+    /**
+     * @param Node $node
+     * @param bool $semicolon
+     */
     protected function atrule(Node $node, $semicolon)
     {
         $name = '@'.$node->name;
@@ -116,6 +146,9 @@ protected function atrule(Node $node, $semicolon)
         }
     }
 
+    /**
+     * @param Node $node
+     */
     protected function body(Node $node)
     {
         $nodeNodesCount = count($node->nodes);
@@ -137,6 +170,10 @@ protected function body(Node $node)
         }
     }
 
+    /**
+     * @param Node $node
+     * @param string $start
+     */
     protected function block(Node $node, $start)
     {
         $between = $this->raw($node, 'between', 'beforeOpen');
@@ -154,6 +191,13 @@ protected function block(Node $node, $start)
         call_user_func($this->builder, '}', $node, 'end');
     }
 
+    /**
+     * @param Node $node
+     * @param string $own
+     * @param string|null $detect
+     *
+     * @return mixed
+     */
     public function raw(Node $node, $own, $detect = null)
     {
         if ($detect === null) {
@@ -215,6 +259,11 @@ public function raw(Node $node, $own, $detect = null)
         return $value;
     }
 
+    /**
+     * @param Node $root
+     *
+     * @return bool|null
+     */
     protected function rawSemicolon(Node $root)
     {
         $value = null;
@@ -232,6 +281,11 @@ protected function rawSemicolon(Node $root)
         return $value;
     }
 
+    /**
+     * @param Node $root
+     *
+     * @return string|null
+     */
     protected function rawEmptyBody(Node $root)
     {
         $value = null;
@@ -249,6 +303,11 @@ protected function rawEmptyBody(Node $root)
         return $value;
     }
 
+    /**
+     * @param Node $root
+     *
+     * @return string|null
+     */
     protected function rawIndent(Node $root)
     {
         $indent = $root->raws->indent;
@@ -272,6 +331,12 @@ protected function rawIndent(Node $root)
         return $value;
     }
 
+    /**
+     * @param Container $root
+     * @param Node $node
+     *
+     * @return string|null
+     */
     protected function rawBeforeComment(Container $root, Node $node)
     {
         $value = null;
@@ -293,6 +358,12 @@ protected function rawBeforeComment(Container $root, Node $node)
         return $value;
     }
 
+    /**
+     * @param Container $root
+     * @param Node $node
+     *
+     * @return string|null
+     */
     protected function rawBeforeDecl(Container $root, Node $node)
     {
         $value = null;
@@ -314,6 +385,11 @@ protected function rawBeforeDecl(Container $root, Node $node)
         return $value;
     }
 
+    /**
+     * @param Container $root
+     *
+     * @return string|null
+     */
     protected function rawBeforeRule(Container $root)
     {
         $value = null;
@@ -334,6 +410,11 @@ protected function rawBeforeRule(Container $root)
         return $value;
     }
 
+    /**
+     * @param Container $root
+     *
+     * @return string|null
+     */
     protected function rawBeforeClose(Container $root)
     {
         $value = null;
@@ -354,6 +435,11 @@ protected function rawBeforeClose(Container $root)
         return $value;
     }
 
+    /**
+     * @param Container $root
+     *
+     * @return string|null
+     */
     protected function rawBeforeOpen(Container $root)
     {
         $value = null;
@@ -371,6 +457,11 @@ protected function rawBeforeOpen(Container $root)
         return $value;
     }
 
+    /**
+     * @param Container $root
+     *
+     * @return string|null
+     */
     protected function rawColon(Container $root)
     {
         $value = null;
@@ -386,6 +477,12 @@ protected function rawColon(Container $root)
         return $value;
     }
 
+    /**
+     * @param Node $node
+     * @param string $detect
+     *
+     * @return string
+     */
     protected function beforeAfter(Node $node, $detect)
     {
         if ($node->type === 'decl') {
@@ -417,6 +514,12 @@ protected function beforeAfter(Node $node, $detect)
         return $value;
     }
 
+    /**
+     * @param Node $node
+     * @param string $prop
+     *
+     * @return mixed|null
+     */
     public function rawValue(Node $node, $prop)
     {
         $value = isset($node->$prop) ? $node->$prop : null;
diff --git a/src/Warning.php b/src/Warning.php
index 9369825..8c95314 100644
--- a/src/Warning.php
+++ b/src/Warning.php
@@ -3,13 +3,13 @@
 namespace PostCSS;
 
 /**
- * Represents a plugin's warning. It can be created using {@link Node#warn}.
+ * Represents a plugin's warning. It can be created using Node->warn.
  *
  * @link https://github.com/postcss/postcss/blob/master/lib/warning.es6
  *
  * @example
- * if ( decl.important ) {
- *     decl.warn(result, 'Avoid !important', { word: '!important' });
+ * if ($decl->important ) {
+ *     $decl->warn($result, 'Avoid !important', ['word' => '!important']);
  * }
  */
 class Warning
@@ -17,7 +17,7 @@ class Warning
     /**
      * The warning message.
      *
-     * @var
+     * @var string
      */
     public $text;
 
@@ -43,23 +43,35 @@ class Warning
     public $node = null;
 
     /**
-     * The name of the plugin that created it will fill this property automatically. this warning. When you call {@link Node#warn}.
+     * The name of the plugin that created it will fill this property automatically when you call Node->warn.
      *
      * @var string|null
      */
     public $plugin = null;
 
+    /**
+     * Index in CSS node string that caused the warning.
+     *
+     * @var int|null
+     */
     public $index = null;
 
+    /**
+     * Word in CSS source that caused the warning.
+     *
+     * @var string|null
+     */
     public $word = null;
 
     /**
      * @param string $text Warning message
-     * @param array $opts   Warning options
-     * @param {Node}   opts.node   CSS node that caused the warning
-     * @param string $opts.word   Word in CSS source that caused the warning
-     * @param {number} opts.index  Index in CSS node string that caused the warning
-     * @param string $opts.plugin  Name of the plugin that created this warning. {@link Result#warn} fills this property automatically
+     * @param array $opts Warning options. {
+     *
+     *     @var Node $node CSS node that caused the warning
+     *     @var string $word Word in CSS source that caused the warning
+     *     @var int $index Index in CSS node string that caused the warning
+     *     @var string $plugin Name of the plugin that created this warning. Result->warn fills this property automatically.
+     * }
      */
     public function __construct($text, array $opts = [])
     {
diff --git a/test/tests/CssSyntaxErrorTest.php b/test/tests/CssSyntaxErrorTest.php
index 83d0793..a107e26 100644
--- a/test/tests/CssSyntaxErrorTest.php
+++ b/test/tests/CssSyntaxErrorTest.php
@@ -16,7 +16,7 @@ class CssSyntaxErrorTest extends \PHPUnit_Framework_TestCase
 {
     /**
      * @param string $css
-     * @param array  $opts
+     * @param array $opts
      *
      * @return CssSyntaxError|null
      */
diff --git a/test/tests/Helpers/DeletableDirectoryTest.php b/test/tests/Helpers/DeletableDirectoryTest.php
index 58ffaec..50ba280 100644
--- a/test/tests/Helpers/DeletableDirectoryTest.php
+++ b/test/tests/Helpers/DeletableDirectoryTest.php
@@ -2,17 +2,8 @@
 
 namespace PostCSS\Tests\Helpers;
 
-use Exception;
-
-abstract class DeletableDirectoryTest extends \PHPUnit_Framework_TestCase
+abstract class DeletableDirectoryTest extends FilesystemTest
 {
-    /**
-     * Return the name (without path) of the temporary directory to create/delete.
-     *
-     * @return string
-     */
-    abstract protected function getDirectoryName();
-
     protected function tearDown()
     {
         parent::tearDown();
@@ -21,27 +12,10 @@ protected function tearDown()
             self::deleteDirectory($dir);
         }
         if (file_exists($dir)) {
-            throw new Exception("Failed to delete directory: $dir");
+            throw new DirectoryRemovalError($dir);
         }
     }
 
-    /**
-     * Return the full path of the temporary directory to create/delete.
-     *
-     * @return string
-     */
-    protected function getDirectoryPath()
-    {
-        return implode(
-            DIRECTORY_SEPARATOR,
-            [
-                dirname(dirname(__DIR__)),
-                'tmp',
-                $this->getDirectoryName(),
-            ]
-        );
-    }
-
     /**
      * Recusrively delete a directory.
      *
@@ -86,50 +60,4 @@ private static function deleteDirectory($dir)
 
         return $result;
     }
-
-    protected function getAbsoluteFilePath($name)
-    {
-        return $this->getDirectoryPath().DIRECTORY_SEPARATOR.trim(str_replace(['/', '\\'], DIRECTORY_SEPARATOR, $name), DIRECTORY_SEPARATOR);
-    }
-
-    /**
-     * @param string $name
-     * @param string $contents
-     *
-     * @return string
-     */
-    protected function createRelativeFile($name, $contents)
-    {
-        $path = $this->getAbsoluteFilePath($name);
-        $this->createAbsoluteFile($path, $contents);
-
-        return $path;
-    }
-
-    /**
-     * @param string $path
-     * @param string $contents
-     */
-    protected function createAbsoluteFile($path, $contents)
-    {
-        $p = strrpos($path, DIRECTORY_SEPARATOR);
-        $subDir = null;
-        if ($p !== false) {
-            $subDir = substr($path, 0, $p);
-            if (!is_dir($subDir)) {
-                @mkdir($subDir, 0777, true);
-                if (!is_dir($subDir)) {
-                    $this->markTestSkipped("Failed to create directory: $subDir");
-                }
-            }
-        }
-        if (@file_put_contents($path, $contents) === false) {
-            if ($subDir === null) {
-                $msg = "Failed to create file: $path";
-            } else {
-                $msg = "Failed to create file $path (detected directory: $subDir)";
-            }
-            $this->markTestSkipped($msg);
-        }
-    }
 }
diff --git a/test/tests/Helpers/DirectoryCreationError.php b/test/tests/Helpers/DirectoryCreationError.php
new file mode 100644
index 0000000..ffe19ab
--- /dev/null
+++ b/test/tests/Helpers/DirectoryCreationError.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace PostCSS\Tests\Helpers;
+
+class DirectoryCreationError extends FilesystemError
+{
+    public function __construct($path, $code = null, $previous = null)
+    {
+        parent::__construct("Failed to create directory $path", $code, $previous);
+        $this->path = $path;
+    }
+}
diff --git a/test/tests/Helpers/DirectoryRemovalError.php b/test/tests/Helpers/DirectoryRemovalError.php
new file mode 100644
index 0000000..716b15b
--- /dev/null
+++ b/test/tests/Helpers/DirectoryRemovalError.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace PostCSS\Tests\Helpers;
+
+class DirectoryRemovalError extends FilesystemError
+{
+    public function __construct($path, $code = null, $previous = null)
+    {
+        parent::__construct("Failed to remove directory $path", $code, $previous);
+        $this->path = $path;
+    }
+}
diff --git a/test/tests/Helpers/FileCreationError.php b/test/tests/Helpers/FileCreationError.php
new file mode 100644
index 0000000..4b7a68f
--- /dev/null
+++ b/test/tests/Helpers/FileCreationError.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace PostCSS\Tests\Helpers;
+
+class FileCreationError extends FilesystemError
+{
+    public function __construct($path, $code = null, $previous = null)
+    {
+        parent::__construct("Failed to create file $filename", $code, $previous);
+        $this->path = $path;
+    }
+}
diff --git a/test/tests/Helpers/FilesystemError.php b/test/tests/Helpers/FilesystemError.php
new file mode 100644
index 0000000..1f228d5
--- /dev/null
+++ b/test/tests/Helpers/FilesystemError.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace PostCSS\Tests\Helpers;
+
+abstract class FilesystemError extends \Exception
+{
+    protected $path;
+
+    public function getPath()
+    {
+        return $this->path;
+    }
+}
diff --git a/test/tests/Helpers/FilesystemTest.php b/test/tests/Helpers/FilesystemTest.php
new file mode 100644
index 0000000..ed99024
--- /dev/null
+++ b/test/tests/Helpers/FilesystemTest.php
@@ -0,0 +1,74 @@
+<?php
+
+namespace PostCSS\Tests\Helpers;
+
+abstract class FilesystemTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * Return the name (without path) of the temporary directory to create/delete.
+     *
+     * @return string
+     */
+    abstract protected function getDirectoryName();
+
+    /**
+     * Return the full path of the temporary directory to create/delete.
+     *
+     * @return string
+     */
+    protected function getDirectoryPath()
+    {
+        return implode(
+            DIRECTORY_SEPARATOR,
+            [
+                dirname(dirname(__DIR__)),
+                'tmp',
+                $this->getDirectoryName(),
+            ]
+            );
+    }
+
+    protected function getAbsoluteFilePath($name)
+    {
+        return $this->getDirectoryPath().DIRECTORY_SEPARATOR.trim(str_replace(['/', '\\'], DIRECTORY_SEPARATOR, $name), DIRECTORY_SEPARATOR);
+    }
+
+    /**
+     * @param string $name
+     * @param string $contents
+     *
+     * @throws FilesystemError
+     *
+     * @return string
+     */
+    protected function createRelativeFile($name, $contents)
+    {
+        $path = $this->getAbsoluteFilePath($name);
+        $this->createAbsoluteFile($path, $contents);
+
+        return $path;
+    }
+
+    /**
+     * @param string $path
+     * @param string $contents
+     *
+     * @throws FilesystemError
+     */
+    protected function createAbsoluteFile($path, $contents)
+    {
+        $p = strrpos($path, DIRECTORY_SEPARATOR);
+        if ($p !== false) {
+            $subDir = substr($path, 0, $p);
+            if (!is_dir($subDir)) {
+                @mkdir($subDir, 0777, true);
+                if (!is_dir($subDir)) {
+                    throw new DirectoryCreationError($subDir);
+                }
+            }
+        }
+        if (@file_put_contents($path, $contents) === false) {
+            throw new FileCreationError($path);
+        }
+    }
+}
diff --git a/test/tests/Helpers/InstantiableNode.php b/test/tests/Helpers/InstantiableNode.php
new file mode 100644
index 0000000..287ba94
--- /dev/null
+++ b/test/tests/Helpers/InstantiableNode.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace PostCSS\Tests\Helpers;
+
+use PostCSS\Node;
+
+class InstantiableNode extends Node
+{
+}
diff --git a/test/tests/IntegrationTest.php b/test/tests/IntegrationTest.php
index fbefabf..c6d3cb3 100644
--- a/test/tests/IntegrationTest.php
+++ b/test/tests/IntegrationTest.php
@@ -5,9 +5,15 @@
 use Exception;
 use PostCSS\Tests\Helpers\DownloadError;
 use PostCSS\Parser;
+use PostCSS\Tests\Helpers\FilesystemError;
 
-class IntegrationTest extends \PHPUnit_Framework_TestCase
+class IntegrationTest extends Helpers\FilesystemTest
 {
+    protected function getDirectoryName()
+    {
+        return 'cache';
+    }
+
     public function providerTestReal()
     {
         return [
@@ -18,12 +24,33 @@ public function providerTestReal()
         ];
     }
 
-    private static function getRemoteContents($url, $parentUrl = null)
+    private function getRemoteContents($url, $parentUrl = null)
     {
         if (strpos($url, 'github:') === 0) {
             $p = explode(':', $url);
             $url = 'https://raw.githubusercontent.com/'.$p[1].'/master/'.$p[2];
         }
+        $cacheName = md5($url.((string) $parentUrl));
+        if (preg_match('/^\w+:\/\/([\w\-]+(?:\.[\w\-]+)+)/', $url, $m)) {
+            $cacheName .= '-'.$m[1];
+        }
+        if (preg_match('/\/([\w\-]+)((?:\.\w+)*)$/', $url, $m)) {
+            $cacheName .= '-'.$m[1];
+            if (isset($m[2]) && $m[2]) {
+                $cacheName .= $m[2];
+            } else {
+                $cacheName .= '.txt';
+            }
+        } else {
+            $cacheName .= '.txt';
+        }
+        $cachePath = $this->getAbsoluteFilePath($cacheName);
+        if (is_file($cachePath)) {
+            $result = @file_get_contents($cachePath);
+            if ($result !== false) {
+                return $result;
+            }
+        }
         $headers = @get_headers($url);
         if (empty($headers)) {
             throw new DownloadError("Failed to get headers of $url");
@@ -54,6 +81,11 @@ private static function getRemoteContents($url, $parentUrl = null)
         switch ($contentEncoding) {
         }
 
+        try {
+            $this->createAbsoluteFile($cachePath, $data);
+        } catch (FilesystemError $x) {
+        }
+
         return $data;
     }
 
@@ -65,9 +97,9 @@ public function testReal($name, $url)
         try {
             $resourceUrls = [];
             if (substr($url, -4) === '.css') {
-                $resourceUrls[$url] = self::getRemoteContents($url);
+                $resourceUrls[$url] = $this->getRemoteContents($url);
             } else {
-                $contents = self::getRemoteContents($url);
+                $contents = $this->getRemoteContents($url);
                 if (!preg_match_all('/[^"]+\.css"|[^\']+\.css\'/', $contents, $m)) {
                     throw new Exception("Can't find CSS links at $url");
                 }
@@ -86,7 +118,7 @@ function ($path) use ($url) {
                     $m[0]
                 );
                 foreach ($files as $file) {
-                    $resourceUrls[$file] = self::getRemoteContents($file);
+                    $resourceUrls[$file] = $this->getRemoteContents($file);
                 }
             }
 
diff --git a/test/tests/MapTest.php b/test/tests/MapTest.php
index 0bd2870..351a4bd 100644
--- a/test/tests/MapTest.php
+++ b/test/tests/MapTest.php
@@ -283,7 +283,11 @@ public function testMissesCheckFilesOnRequires()
             'map' => true,
         ]);
 
-        $this->createAbsoluteFile($file.'.map', $step1->map);
+        try {
+            $this->createAbsoluteFile($file.'.map', $step1->map);
+        } catch (Helpers\FilesystemError $x) {
+            $this->markTestSkipped($x->getMessage());
+        }
         $step2 = static::lighter()->process($step1->css, [
             'from' => $file,
             'to' => 'b.css',
@@ -364,7 +368,11 @@ public function testUsesMapFromSubdirIfItWrittenAsAFile()
         $source = static::consumer($step1->map)->originalPositionFor(['line' => 1, 'column' => 0])['source'];
         $this->assertSame('../../source/a.css', $source);
 
-        $file = $this->createRelativeFile('one/maps/b.css.map', $step1->map);
+        try {
+            $file = $this->createRelativeFile('one/maps/b.css.map', $step1->map);
+        } catch (Helpers\FilesystemError $x) {
+            $this->markTestSkipped($x->getMessage());
+        }
         $step2 = static::doubler()->process($step1->css, [
             'from' => $this->getAbsoluteFilePath('one/b.css'),
             'to' => $this->getAbsoluteFilePath('two/c.css'),
diff --git a/test/tests/NodeTest.php b/test/tests/NodeTest.php
index a74a7c9..93b3ef4 100644
--- a/test/tests/NodeTest.php
+++ b/test/tests/NodeTest.php
@@ -13,7 +13,6 @@
 use PostCSS\Parser;
 use PostCSS\Processor;
 use PostCSS\Warning;
-use React\Promise\FulfilledPromise;
 
 class NodeTest extends \PHPUnit_Framework_TestCase
 {
@@ -70,17 +69,18 @@ function ($css, $result) use (&$warning) {
         );
 
         $me = $this;
-        $result = (new Processor([$warner]))->process('a{}')->then(
-            function ($result) use ($me, &$warning) {
-                $me->assertInstanceOf(Warning::class, $warning);
-                $me->assertSame('FIRST!', $warning->text);
-                $me->assertSame('warner', $warning->plugin);
-                $me->assertSame([$warning], $result->warnings());
-            },
-            function ($error) {
-            }
-        );
-        $this->assertInstanceOf(FulfilledPromise::class, $result);
+        (new Processor([$warner]))->process('a{}')
+            ->then(
+                function ($result) use ($me, &$warning) {
+                    $me->assertInstanceOf(Warning::class, $warning);
+                    $me->assertSame('FIRST!', $warning->text);
+                    $me->assertSame('warner', $warning->plugin);
+                    $me->assertSame([$warning], $result->warnings());
+                },
+                function ($error) {
+                }
+            )
+            ->done();
     }
 
     public function testWarnAcceptsOptions()
diff --git a/test/tests/PostCSSTest.php b/test/tests/PostCSSTest.php
index 96571e4..3b31b74 100644
--- a/test/tests/PostCSSTest.php
+++ b/test/tests/PostCSSTest.php
@@ -4,7 +4,6 @@
 
 use PostCSS\Processor;
 use PostCSS\Plugin\ClosurePlugin;
-use React\Promise\FulfilledPromise;
 use PostCSS\Parser;
 use PostCSS\Root;
 use PostCSS\Comment;
@@ -150,14 +149,15 @@ function ($str = 'bar') {
         $this->assertSame('a{value:baz}', $result2->css);
 
         $me = $this;
-        $cr = $plugin->process('a{value:foo}', [])->then(
-            function ($result) use ($me) {
-                $me->assertSame('a{value:bar}', $result->css);
-            },
-            function () {
-            }
-        );
-        $this->assertInstanceOf(FulfilledPromise::class, $cr);
+        $plugin->process('a{value:foo}', [])
+            ->then(
+                function ($result) use ($me) {
+                    $me->assertSame('a{value:bar}', $result->css);
+                },
+                function () {
+                }
+            )
+            ->done();
     }
 
     public function testContainsParser()
diff --git a/test/tests/PreviousMapTest.php b/test/tests/PreviousMapTest.php
index 1e48ee5..7f9dc94 100644
--- a/test/tests/PreviousMapTest.php
+++ b/test/tests/PreviousMapTest.php
@@ -142,7 +142,11 @@ public function testRaisesOnUnknownMapFormat()
 
     public function testReadsMapFromAnnotation()
     {
-        $file = $this->createRelativeFile('a.map', static::getMap());
+        try {
+            $file = $this->createRelativeFile('a.map', static::getMap());
+        } catch (Helpers\FilesystemError $x) {
+            $this->markTestSkipped($x->getMessage());
+        }
         $root = Parser::parse("a{}\n/*# sourceMappingURL=a.map */", ['from' => $file]);
 
         $this->assertSame(static::getMap(), $root->source['input']->map->text);
@@ -180,7 +184,11 @@ public function testShouldAcceptAnEmptyMappingsString()
     public function testShouldAcceptAFunction()
     {
         $css = "body{}\n/*# sourceMappingURL=a.map */";
-        $file = $this->createRelativeFile('previous-sourcemap-function.map', static::getMap());
+        try {
+            $file = $this->createRelativeFile('previous-sourcemap-function.map', static::getMap());
+        } catch (Helpers\FilesystemError $x) {
+            $this->markTestSkipped($x->getMessage());
+        }
         $opts = [
             'map' => [
                 'prev' => function (/* from */) use ($file) {
@@ -195,24 +203,25 @@ public function testShouldAcceptAFunction()
 
     public function testShouldCallFunctionWithOptsFrom()
     {
-        $numberOfAssertions = 0;
-
         $css = "body{}\n/*# sourceMappingURL=a.map */";
-        $file = $this->createRelativeFile('previous-sourcemap-function.map', static::getMap());
+        try {
+            $file = $this->createRelativeFile('previous-sourcemap-function.map', static::getMap());
+        } catch (Helpers\FilesystemError $x) {
+            $this->markTestSkipped($x->getMessage());
+        }
         $me = $this;
         $opts = [
             'from' => 'a.css',
             'map' => [
-                'prev' => function ($from) use ($me, $file, &$numberOfAssertions) {
+                'prev' => function ($from) use ($me, $file) {
                     $me->assertSame('a.css', $from);
-                    ++$numberOfAssertions;
 
                     return $file;
                 },
             ],
         ];
         Parser::parse($css, $opts);
-        $this->assertSame(1, $numberOfAssertions);
+        $this->assertSame(1, static::getCount());
     }
 
     public function testShouldRaiseWhenFunctionReturnsInvalidPath()
diff --git a/test/tests/ProcessorTest.php b/test/tests/ProcessorTest.php
index a18059f..0365b3d 100644
--- a/test/tests/ProcessorTest.php
+++ b/test/tests/ProcessorTest.php
@@ -3,14 +3,14 @@
 namespace PostCSS\Tests;
 
 use PostCSS\Exception\CssSyntaxError;
+use PostCSS\LazyResult;
+use PostCSS\Node;
 use PostCSS\Parser;
+use PostCSS\Path\NodeJS as Path;
 use PostCSS\Plugin\ClosurePlugin;
 use PostCSS\Processor;
-use PostCSS\Node;
-use PostCSS\Root;
-use PostCSS\Path\NodeJS as Path;
-use PostCSS\LazyResult;
 use PostCSS\Result;
+use PostCSS\Root;
 
 class ProcessorTest extends \PHPUnit_Framework_TestCase
 {
@@ -235,54 +235,46 @@ public function testCallsAllPluginsOnce()
             $calls .= 'b';
         });
 
-        $assertions = 0;
         $me = $this;
-        $result = (new Processor([$a, $b]))
+        (new Processor([$a, $b]))
             ->process('')
             ->then(
-                function () use ($me, &$calls, &$assertions) {
+                function () use ($me, &$calls) {
                     $me->assertSame('ab', $calls);
-                    ++$assertions;
                 },
                 function () {
                 }
-            );
-        $this->assertSame(1, $assertions);
+            )
+            ->done();
+        $this->assertSame(1, static::getCount());
     }
 
     public function testParsesConvertsAndStringifiesCSS()
     {
-        $assertions = 0;
         $me = $this;
         $a = new ClosurePlugin(
-            function ($css) use ($me, &$assertions) {
+            function ($css) use ($me) {
                 $me->assertInstanceOf(Root::class, $css);
-                ++$assertions;
             }
         );
         $this->assertInternalType('string', (new Processor([$a]))->process('a {}')->css);
-        $this->assertSame(1, $assertions);
+        $this->assertSame(2, static::getCount());
     }
 
     public function testSendResultToPlugins()
     {
         $processor = new Processor();
-        $assertions = 0;
         $me = $this;
         $a = new ClosurePlugin(
-            function ($css, $result) use ($me, &$assertions, $processor) {
+            function ($css, $result) use ($me, $processor) {
                 $me->assertInstanceOf(Result::class, $result);
-                ++$assertions;
                 $me->assertSame($processor, $result->processor);
-                ++$assertions;
                 $me->assertSame(['map' => true], $result->opts);
-                ++$assertions;
                 $me->assertSame($css, $result->root);
-                ++$assertions;
             }
         );
         $processor->usePlugin($a)->process('a {}', ['map' => true])->css;
-        $this->assertSame(4, $assertions);
+        $this->assertSame(4, static::getCount());
     }
 
     public function testAcceptsSourceMapFromPostCSS()
@@ -309,156 +301,152 @@ public function testAcceptsSourceMapFromPostCSS()
     public function testWorksAsyncWithoutPlugins()
     {
         $me = $this;
-        $assertions = 0;
-
-        return (new Processor())->process('a {}')->then(
-            function ($result) use ($me, &$assertions) {
-                $me->assertSame('a {}', $result->css);
-                ++$assertions;
-            },
-            function () {
-            }
-        );
-        $this->assertSame(1, $assertions);
+        (new Processor())->process('a {}')
+            ->then(
+                function ($result) use ($me) {
+                    $me->assertSame('a {}', $result->css);
+                },
+                function () {
+                }
+            )
+            ->done();
+        $this->assertSame(1, static::getCount());
     }
 
     public function testSetsLastPluginToResult()
     {
-        $assertions = 0;
         $me = $this;
-        $plugin1 = new ClosurePlugin(function ($css, $result) use ($me, &$assertions, &$plugin1) {
+        $plugin1 = new ClosurePlugin(function ($css, $result) use ($me, &$plugin1) {
             $me->assertSame($result->lastPlugin, $plugin1);
-            ++$assertions;
         });
-        $plugin2 = new ClosurePlugin(function ($css, $result) use ($me, &$assertions, &$plugin2) {
+        $plugin2 = new ClosurePlugin(function ($css, $result) use ($me, &$plugin2) {
             $me->assertSame($result->lastPlugin, $plugin2);
-            ++$assertions;
         });
 
         $processor = new Processor([$plugin1, $plugin2]);
-        $processor->process('a{}')->then(
-            function ($result) use ($me, &$assertions, $plugin2) {
-                $me->assertSame($result->lastPlugin, $plugin2);
-                ++$assertions;
-            },
-            function () {
-            }
-        );
-        $this->assertSame(3, $assertions);
+        $processor->process('a{}')
+            ->then(
+                function ($result) use ($me, $plugin2) {
+                    $me->assertSame($result->lastPlugin, $plugin2);
+                },
+                function () {
+                }
+            )
+            ->done();
+        $this->assertSame(3, static::getCount());
     }
 
     public function testUsesCustomParsers()
     {
-        $assertions = 0;
         $me = $this;
         $processor = new Processor([]);
         $processor->process(
             'a{}',
             ['parser' => [self::class, 'prs']]
-        )->then(
-            function ($result) use ($me, &$assertions) {
-                $me->assertSame('ok', $result->css);
-                ++$assertions;
-            },
-            function () {
-            }
-        );
-        $this->assertSame(1, $assertions);
+        )
+            ->then(
+                function ($result) use ($me) {
+                    $me->assertSame('ok', $result->css);
+                },
+                function () {
+                }
+            )
+            ->done();
+        $this->assertSame(1, static::getCount());
     }
 
     public function testUsesCustomParsersFromObject()
     {
         $me = $this;
-        $assertions = 0;
         $processor = new Processor([]);
         $syntax = ['parse' => [self::class, 'prs'], 'stringify' => [self::class, 'str']];
         $processor->process(
             'a{}', ['parser' => $syntax]
-        )->then(
-            function ($result) use ($me, &$assertions) {
-                $me->assertSame('ok', $result->css);
-                ++$assertions;
-            },
-            function () {
-            }
-        );
-        $this->assertSame(1, $assertions);
+        )
+            ->then(
+                function ($result) use ($me) {
+                    $me->assertSame('ok', $result->css);
+                },
+                function () {
+                }
+            )
+            ->done();
+        $this->assertSame(1, static::getCount());
     }
 
     public function testUsesCustomStringifier()
     {
         $me = $this;
-        $assertions = 0;
         $processor = new Processor([]);
         $processor->process(
             'a{}',
             ['stringifier' => [self::class, 'str']]
-        )->then(
-            function ($result) use ($me, &$assertions) {
-                $me->assertSame('!', $result->css);
-                ++$assertions;
-            },
-            function () {
-            }
-        );
-        $this->assertSame(1, $assertions);
+        )
+            ->then(
+                function ($result) use ($me) {
+                    $me->assertSame('!', $result->css);
+                },
+                function () {
+                }
+            )
+            ->done();
+        $this->assertSame(1, static::getCount());
     }
 
     public function testUsesCustomStringifierFromObject()
     {
         $me = $this;
-        $assertions = 0;
         $processor = new Processor([]);
         $syntax = ['parse' => [self::class, 'prs'], 'stringify' => [self::class, 'str']];
         $processor->process(
             '',
             ['stringifier' => $syntax]
-        )->then(
-            function ($result) use ($me, &$assertions) {
-                $me->assertSame('!', $result->css);
-                ++$assertions;
-            },
-            function () {
-            }
-        );
-        $this->assertSame(1, $assertions);
+        )
+            ->then(
+                function ($result) use ($me) {
+                    $me->assertSame('!', $result->css);
+                },
+                function () {
+                }
+            )
+            ->done();
+        $this->assertSame(1, static::getCount());
     }
 
     public function testUsesCustomStringifierWithSourceMaps()
     {
         $me = $this;
-        $assertions = 0;
         $processor = new Processor([]);
         $processor->process('a{}', ['map' => true, 'stringifier' => [self::class, 'str']])
-        ->then(
-            function ($result) use ($me, &$assertions) {
-                $me->assertRegExp('/!\n\/\*# sourceMap/', $result->css);
-                ++$assertions;
-            },
-            function () {
-            }
-        );
-        $this->assertSame(1, $assertions);
+            ->then(
+                function ($result) use ($me) {
+                    $me->assertRegExp('/!\n\/\*# sourceMap/', $result->css);
+                },
+                function () {
+                }
+            )
+            ->done();
+        $this->assertSame(1, static::getCount());
     }
 
     public function testUsesCustomSyntax()
     {
         $me = $this;
-        $assertions = 0;
         $processor = new Processor([]);
         $syntax = ['parse' => [self::class, 'prs'], 'stringify' => [self::class, 'str']];
 
-        return $processor->process(
+        $processor->process(
             'a{}',
             ['syntax' => $syntax]
-        )->then(
-            function ($result) use ($me, &$assertions) {
-                $me->assertSame('ok!', $result->css);
-                ++$assertions;
-            },
-            function () {
-            }
-        );
-        $this->assertSame(1, $assertions);
+        )
+            ->then(
+                function ($result) use ($me) {
+                    $me->assertSame('ok!', $result->css);
+                },
+                function () {
+                }
+            )
+            ->done();
+        $this->assertSame(1, static::getCount());
     }
 }
diff --git a/test/tests/RuleTest.php b/test/tests/RuleTest.php
index ef39820..647f591 100644
--- a/test/tests/RuleTest.php
+++ b/test/tests/RuleTest.php
@@ -16,13 +16,13 @@ public function testInitializesWithProperties()
     public function testReturnsArrayInSelectors()
     {
         $rule = new Rule(['selector' => 'a,b']);
-        $this->assertSame(['a', 'b'], $rule->getSelectors());
+        $this->assertSame(['a', 'b'], $rule->selectors);
     }
 
     public function testTrimsSelectors()
     {
         $rule = new Rule(['selector' => ".a\n, .b  , .c"]);
-        $this->assertSame(['.a', '.b', '.c'], $rule->getSelectors());
+        $this->assertSame(['.a', '.b', '.c'], $rule->selectors);
     }
 
     public function testIsSmartAboutSelectorsCommas()
@@ -32,35 +32,36 @@ public function testIsSmartAboutSelectorsCommas()
         ]);
         $this->assertSame(
             ['[foo=\'a, b\']', 'a:-moz-any(:focus, [href*=\',\'])'],
-            $rule->getSelectors()
+            $rule->selectors
         );
     }
 
     public function testReceiveArrayInSelectors()
     {
         $rule = new Rule(['selector' => 'i, b']);
-        $rule->setSelectors(['em', 'strong']);
+        $rule->selectors = ['em', 'strong'];
         $this->assertSame('em, strong', $rule->selector);
     }
 
     public function testSavesSeparatorInSelectors()
     {
         $rule = new Rule(['selector' => "i,\nb"]);
-        $rule->setSelectors(['em', 'strong']);
+        $rule->selectors = ['em', 'strong'];
         $this->assertSame("em,\nstrong", $rule->selector);
     }
 
     public function testUsesBetweenToDetectSeparatorInSelectors()
     {
         $rule = new Rule(['selector' => 'b', 'raws' => ['between' => '']]);
-        $rule->setSelectors(['b', 'strong']);
+        $rule->selectors = ['b', 'strong'];
         $this->assertSame('b,strong', $rule->selector);
     }
 
     public function testUsesSpaceInSeparatorBeDefaultInSelectors()
     {
         $rule = new Rule(['selector' => 'b']);
-        $rule->setSelectors(['b', 'strong']);
+        $rule->selectors = ['b', 'strong'];
+        $rule->_selector = 1;
         $this->assertSame('b, strong', $rule->selector);
     }
 
diff --git a/test/tests/StringifierTest.php b/test/tests/StringifierTest.php
index 1320932..021566b 100644
--- a/test/tests/StringifierTest.php
+++ b/test/tests/StringifierTest.php
@@ -4,11 +4,11 @@
 
 use PostCSS\AtRule;
 use PostCSS\Declaration;
-use PostCSS\Node;
+use PostCSS\Parser;
 use PostCSS\Root;
 use PostCSS\Rule;
 use PostCSS\Stringifier;
-use PostCSS\Parser;
+use PostCSS\Tests\Helpers\InstantiableNode;
 
 class StringifierTest extends \PHPUnit_Framework_TestCase
 {
@@ -25,11 +25,11 @@ protected function setUp()
 
     public function testCreatesTrimmedRawProperty()
     {
-        $b = new Node(['one' => 'trim']);
+        $b = new InstantiableNode(['one' => 'trim']);
         $b->raws->one = ['value' => 'trim', 'raw' => 'raw'];
         $this->assertSame('raw', $this->str->rawValue($b, 'one'));
 
-        $b = new Node(['one' => 'trim']);
+        $b = new InstantiableNode(['one' => 'trim']);
         $b->raws->one = (object) ['value' => 'trim', 'raw' => 'raw'];
         $this->assertSame('raw', $this->str->rawValue($b, 'one'));
 
@@ -39,7 +39,7 @@ public function testCreatesTrimmedRawProperty()
 
     public function testWorksWithoutRawValueMagic()
     {
-        $b = new Node();
+        $b = new InstantiableNode();
         $b->one = '1';
         $this->assertSame('1', $b->one);
         $this->assertSame('1', $this->str->rawValue($b, 'one'));