added tests for the public API

Author: mightyaleksey

test/plugins.js

@@ -1,16 +1,14 @@
 import { equal } from 'assert';
 import { identity } from 'lodash';
+import { dropCache } from '../utils/sugar';
 import hook from '../src';
 
 import ExtractImports from 'postcss-modules-extract-imports';
 import LocalByDefault from 'postcss-modules-local-by-default';
 import Scope from 'postcss-modules-scope';
 
 describe('plugins', () => {
-  beforeEach(() => {
-    // clearing cache
-    delete require.cache[require.resolve('awesome-theme/oceanic.css')];
-  });
+  afterEach(() => dropCache('awesome-theme/oceanic.css'));
 
   describe('custom generateScopedName() function', () => {
     before(() => hook({generateScopedName: identity}));

test/public-api.js

@@ -1,80 +1,137 @@
-import { constant } from 'lodash';
+import { noop } from 'lodash';
 import { equal, ok } from 'assert';
+import { dropCache, spy, Through } from '../utils/sugar';
 import hook from '../src';
 
 describe('public api', () => {
-  beforeEach(() => {
-    // clearing cache
-    delete require.cache[require.resolve('awesome-theme/oceanic.css')];
-  });
+  afterEach(() => dropCache('awesome-theme/oceanic.css'));
 
-  describe('preprocessCss()', () => {
-    describe('content of the file and filename are provided to the preprocessCss function', () => {
-      let providedCSS;
-      let providedFilename;
+  describe('extending list of plugins', () => {
+    describe('"prepend" should add plugins in the beginning of the pipeline', () => {
+      let processor;
 
       beforeEach(() => {
-        const spy = (content, filename) => {
-          providedCSS = content;
-          providedFilename = filename;
-          return content;
-        };
+        processor = spy(noop);
 
-        hook({preprocessCss: spy});
-        require('awesome-theme/oceanic.css');
-      });
+        hook({
+          prepend: [
+            new Through({processor: processor}),
+          ],
+        });
 
-      it('content of file should be provided', () => {
-        equal(typeof providedCSS, 'string');
-        ok(providedCSS.length);
+        require('awesome-theme/oceanic.css');
       });
 
-      it('filename should be provided', () => {
-        equal(providedFilename, require.resolve('awesome-theme/oceanic.css'));
-      });
+      it('processor should be called', () =>
+        ok(processor.called));
     });
 
-    describe('providing empty string constantly', () => {
-      before(() => hook({preprocessCss: constant('')}));
+    describe('"append" should add plugins to the pipeline', () => {
+      let processor;
+
+      beforeEach(() => {
+        processor = spy(noop);
+
+        hook({
+          append: [
+            new Through({processor: processor}),
+          ],
+        });
 
-      it('should return an empty result', () => {
-        const tokens = require('awesome-theme/oceanic.css');
-        equal(Object.keys(tokens).length, 0);
+        require('awesome-theme/oceanic.css');
       });
+
+      it('processor should be called', () =>
+        ok(processor.called));
     });
 
-    describe('providing nothing should reset preProcess', () => {
-      before(() => hook());
+    describe('"use" should set the new list of plugins', () => {
+      let appendProcessor;
+      let prependProcessor;
+      let useProcessor;
+
+      beforeEach(() => {
+        appendProcessor = spy(noop);
+        prependProcessor = spy(noop);
+        useProcessor = spy(noop);
+
+        hook({
+          append: [
+            new Through({processor: appendProcessor}),
+          ],
+          prepend: [
+            new Through({processor: prependProcessor}),
+          ],
+          use: [
+            new Through({processor: useProcessor}),
+          ],
+        });
 
-      it('should return the "color" token', () => {
-        const tokens = require('awesome-theme/oceanic.css');
-        ok(tokens.color);
+        require('awesome-theme/oceanic.css');
       });
+
+      it('plugin added by append option should not be called', () =>
+        ok(!appendProcessor.called));
+
+      it('plugin added by prepend option should not be called', () =>
+        ok(!prependProcessor.called));
+
+      it('plugin added by use option should be called', () =>
+        ok(useProcessor.called));
     });
   });
 
-  describe('processCss()', () => {
-    let providedCSS;
-    let providedFilename;
+  describe('setting custom processors for the CSS', () => {
+    describe('"preprocessCss()" should transform CSS before the PostCSS', () => {
+      let processor;
+      let providedFilename;
+      let providedContent;
 
-    beforeEach(() => {
-      const spy = (content, filename) => {
-        providedCSS = content;
-        providedFilename = filename;
-        return content;
-      };
+      beforeEach(() => {
+        processor = spy((content, filename) => {
+          providedFilename = filename;
+          providedContent = content;
+          return '';
+        });
 
-      hook({processCss: spy});
-      require('awesome-theme/oceanic.css');
-    });
+        hook({preprocessCss: processor});
+        require('awesome-theme/oceanic.css');
+      });
+
+      it('processor should be called', () =>
+        ok(processor.called));
 
-    it('content of file should be provided', () => {
-      equal(typeof providedCSS, 'string');
-      ok(providedCSS.length);
+      it('filename should be provided', () =>
+        equal(providedFilename, require.resolve('awesome-theme/oceanic.css')));
+
+      it('content of the file should be provided', () =>
+        ok(providedContent.length));
     });
 
-    it('filename should be provided', () => {
-      equal(providedFilename, require.resolve('awesome-theme/oceanic.css'));
+    describe('"processCss()" should transform CSS after the PostCSS', () => {
+      let processor;
+      let providedFilename;
+      let providedContent;
+
+      beforeEach(() => {
+        processor = spy((content, filename) => {
+          providedFilename = filename;
+          providedContent = content;
+          return '';
+        });
+
+        hook({processCss: processor});
+        require('awesome-theme/oceanic.css');
+      });
+
+      it('processor should be called', () =>
+        ok(processor.called));
+
+      it('filename should be provided', () =>
+        equal(providedFilename, require.resolve('awesome-theme/oceanic.css')));
+
+      it('content of the file should be provided', () =>
+        ok(providedContent.length));
     });
   });
 });

utils/sugar.js

@@ -0,0 +1,36 @@
+import { identity } from 'lodash';
+import { plugin } from 'postcss';
+
+/**
+ * @param {string} moduleName
+ */
+export function dropCache(moduleName) {
+  delete require.cache[require.resolve(moduleName)];
+}
+
+/**
+ * @param  {function} fn
+ * @return {function}
+ */
+export function spy(fn) {
+  const wrapper = function wrapper() {
+    wrapper.called = true;
+    wrapper.times++;
+    return fn.apply(this, arguments);
+  };
+
+  wrapper.called = false;
+  wrapper.times = 0;
+
+  return wrapper;
+}
+
+/**
+ * Simple PostCSS plugin for the test purpose
+ * @param  {object} opts
+ * @return {Function}
+ */
+export const Through = plugin('through', function through(opts = {}) {
+  const processor = opts.processor || identity;
+  return css => processor(css);
+});