[TASK] Extract value parsing functional tests (part 1) (#1084)

In the tests, we should test parsing and rendering separately
as this makes debugging test failures a lot easier.

Part of #1057

Author: oliverklee

tests/Functional/Value/ValueTest.php

@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabberworm\CSS\Tests\Functional\Value;
+
+use PHPUnit\Framework\TestCase;
+use Sabberworm\CSS\Parsing\ParserState;
+use Sabberworm\CSS\Settings;
+use Sabberworm\CSS\Value\CSSFunction;
+use Sabberworm\CSS\Value\Size;
+use Sabberworm\CSS\Value\Value;
+
+/**
+ * @covers \Sabberworm\CSS\Value\Value
+ */
+final class ValueTest extends TestCase
+{
+    /**
+     * the default set of delimiters for parsing most values
+     *
+     * @see \Sabberworm\CSS\Rule\Rule::listDelimiterForRule
+     *
+     * @var list<non-empty-string>
+     */
+    private const DEFAULT_DELIMITERS = [',', ' ', '/'];
+
+    /**
+     * @test
+     */
+    public function parsesFirstArgumentInMaxFunction(): void
+    {
+        $parsedValue = Value::parseValue(
+            new ParserState('max(300px, 400px);', Settings::create()),
+            self::DEFAULT_DELIMITERS
+        );
+
+        self::assertInstanceOf(CSSFunction::class, $parsedValue);
+        $size = $parsedValue->getArguments()[0];
+        self::assertInstanceOf(Size::class, $size);
+        self::assertSame(300.0, $size->getSize());
+        self::assertSame('px', $size->getUnit());
+        self::assertFalse($size->isColorComponent());
+    }
+}