fix(preprocessor): Support CoffeeScript when using RequireJS

Adds support for using RequireJS with CoffeeScript code by changing
the file extension from `.coffee` to `.js`. RequireJS automatically
adds the `.js` suffix to files and it doesn't seem possible to change
it.

Closes #177

README.md

@@ -54,7 +54,11 @@ module.exports = function(config) {
 ### CoffeeScript
 
 For an example on how to use with [CoffeeScript](http://coffeescript.org/)
-see [examples/coffee](examples/coffee).
+see [examples/coffee](examples/coffee). For an example of how to use with
+CoffeeScript and the RequireJS module loader, see
+[examples/coffee-requirejs](examples/coffee-requirejs) (and also see
+the `useJSExtensionForCoffeeScript` option in
+[docs/configuration.md](docs/configuration.md)).
 
 ### Advanced, multiple reporters
 

docs/configuration.md

@@ -220,3 +220,26 @@ coverageReporter: {
   }
 }
 ```
+
+### `useJSExtensionForCoffeeScript`
+
+**Type:** boolean
+
+**Description:** If set to `true`, then CoffeeScript files instrumented
+with [Ibrik](https://github.com/Constellation/ibrik) will use the `.js`
+extension for the transpiled source (without this option, the JavaScript
+files will keep the original `.coffee` extension). This option is required
+if you use a module loader such as [RequireJS](http://requirejs.org/) that
+expects files to use a `.js` extension.
+
+Example of using RequireJS with CoffeeScript:
+
+```coffeescript
+coverageReporter:
+  useJSExtensionForCoffeeScript: true
+  instrumenters:
+    ibrik : require('ibrik')
+  instrumenter:
+    '**/*.coffee': 'ibrik'
+# ...
+```

examples/coffee-requirejs/calculator.coffee

@@ -0,0 +1,9 @@
+define [], ->
+
+  # Some code under test
+  plus: (a, b) ->
+    a + b
+
+  # not covered
+  minus: (a, b) ->
+    a - b

examples/coffee-requirejs/karma.conf.coffee

@@ -0,0 +1,53 @@
+module.exports = (config) ->
+  config.set
+    frameworks: ['mocha', 'requirejs']
+
+    files: [
+      # We do not want any files to execute automatically
+      {pattern: 'calculator.coffee', included: false}
+      {pattern: 'test.coffee', included: false}
+
+      # Except for this one. This one shall execute.
+      'requirejs.karma.coffee'
+    ]
+
+    browsers: ['Firefox']
+
+    coffeePreprocessor:
+      options:
+        sourceMap: true
+
+    preprocessors:
+      # source files, that you wanna generate coverage for
+      # do not include tests or libraries
+      # (these files will be instrumented by Istanbul via Ibrik unless
+      # specified otherwise in coverageReporter.instrumenter)
+      'calculator.coffee': 'coverage'
+
+      # note: project files will already be converted to
+      # JavaScript via coverage preprocessor.
+      # Thus, you'll have to limit the CoffeeScript preprocessor
+      # to uncovered files.
+      'test.coffee': 'coffee'
+      'requirejs.karma.coffee': 'coffee'
+
+    coverageReporter:
+      type: 'text-summary'
+      useJSExtensionForCoffeeScript: true
+      instrumenters:
+        ibrik : require('ibrik')
+      instrumenter:
+        '**/*.coffee': 'ibrik'
+
+    # coverage reporter generates the coverage
+    reporters: ['dots', 'coverage']
+
+    plugins: [
+      require('../../lib/index')
+      'karma-mocha'
+      'karma-requirejs'
+      'karma-coffee-preprocessor'
+      'karma-firefox-launcher'
+    ]
+
+    singleRun: true

examples/coffee-requirejs/package.json

@@ -0,0 +1,22 @@
+{
+  "name": "karma-coverage-coffee-example",
+  "version": "1.0.0",
+  "description": "Demonstrate the usage of karma-coverage with CoffeeScript",
+  "main": "",
+  "scripts": {
+    "test": "./node_modules/karma/bin/karma start"
+  },
+  "author": "Lloyd Smith II <[email protected]>",
+  "license": "MIT",
+  "dependencies": {},
+  "devDependencies": {
+    "coffee-script": "latest",
+    "ibrik": "^2.0.0",
+    "karma": "^0.13.9",
+    "karma-coffee-preprocessor": "latest",
+    "karma-firefox-launcher": "latest",
+    "karma-mocha": "latest",
+    "karma-requirejs": "^0.2.2",
+    "requirejs": "^2.1.20"
+  }
+}

examples/coffee-requirejs/requirejs.karma.coffee

@@ -0,0 +1,6 @@
+# A minimal requirejs configuration
+require.config
+  baseUrl: '/base'
+  deps: ['test']
+  callback: ->
+    window.__karma__.start()

examples/coffee-requirejs/test.coffee

@@ -0,0 +1,9 @@
+define ['calculator'], (calculator) ->
+
+  describe 'calculator', ->
+
+    it 'should pass', ->
+      true is true
+
+    it 'should work', ->
+      calculator.plus(1, 2) is 3

gruntfile.js

@@ -54,6 +54,9 @@ module.exports = function (grunt) {
     karma: {
       coffee: {
         configFile: 'examples/coffee/karma.conf.coffee'
+      },
+      coffeeRequireJS: {
+        configFile: 'examples/coffee-requirejs/karma.conf.coffee'
       }
     },
     eslint: {

lib/preprocessor.js

@@ -31,11 +31,13 @@ function createCoveragePreprocessor (logger, helper, basePath, reporters, covera
   var instrumenterOverrides = {}
   var instrumenters = {istanbul: istanbul}
   var includeAllSources = false
+  var useJSExtensionForCoffeeScript = false
 
   if (coverageReporter) {
     instrumenterOverrides = coverageReporter.instrumenter
     instrumenters = extend({istanbul: istanbul}, coverageReporter.instrumenters)
     includeAllSources = coverageReporter.includeAllSources === true
+    useJSExtensionForCoffeeScript = coverageReporter.useJSExtensionForCoffeeScript === true
   }
 
   var sourceCache = globalSourceCache.get(basePath)
@@ -137,6 +139,11 @@ function createCoveragePreprocessor (logger, helper, basePath, reporters, covera
         }
       }
 
+      // RequireJS expects JavaScript files to end with `.js`
+      if (useJSExtensionForCoffeeScript && instrumenterLiteral === 'ibrik') {
+        file.path = file.path.replace(/\.coffee$/, '.js')
+      }
+
       done(instrumentedCode)
     })
   }

package.json

@@ -49,7 +49,9 @@
     "mocha": "^2.2.5",
     "mocks": "0.0.15",
     "sinon": "^1.14.1",
-    "sinon-chai": "^2.8.0"
+    "sinon-chai": "^2.8.0",
+    "karma-requirejs": "^0.2.2",
+    "requirejs": "^2.1.20"
   },
   "contributors": [
     "dignifiedquire <[email protected]>",

test/preprocessor.spec.coffee

@@ -158,3 +158,29 @@ describe 'preprocessor', ->
     process ORIGINAL_CODE, file, (preprocessedCode) ->
       expect(coverageMap.get()['./file.js']).to.not.exist
       done()
+
+  it 'should change extension of CoffeeScript files when given `useJSExtensionForCoffeeScript`', (done) ->
+
+    ibrikInstrumenter  = ->
+    ibrikInstrumenter::instrument = (_a, _b, callback) ->
+      callback()
+      return
+
+    process = createPreprocessor mockLogger, helper, '/base/path', ['coverage', 'progress'],
+      instrumenters:
+        ibrik :
+          Instrumenter : ibrikInstrumenter
+      instrumenter:
+        '**/*.coffee': 'ibrik'
+      useJSExtensionForCoffeeScript: true
+
+    file = new File '/base/path/file.coffee'
+
+    process ORIGINAL_COFFEE_CODE, file, (preprocessedCode) ->
+      sandbox =
+        a: true
+        something: ->
+
+      vm.runInNewContext preprocessedCode, sandbox
+      expect(file.path).to.equal '/base/path/file.js'
+      done()