Updated the files.

my-app/node_modules/karma-coverage/examples/coffee/karma.conf.coffee

@@ -0,0 +1,45 @@
+module.exports = (config) ->
+  config.set
+    frameworks: ['mocha']
+
+    files: [
+      '*.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)
+      'plus.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'
+
+    coverageReporter:
+      type: 'html'
+      instrumenters:
+        ibrik : require('ibrik')
+      instrumenter:
+        '**/*.coffee': 'ibrik'
+
+    # coverage reporter generates the coverage
+    reporters: ['dots', 'coverage']
+
+    plugins: [
+      require('../../lib/index')
+      'karma-mocha'
+      'karma-coffee-preprocessor'
+      'karma-firefox-launcher'
+    ]
+
+    singleRun: true

my-app/node_modules/karma-coverage/examples/coffee/package.json

@@ -0,0 +1,20 @@
+{
+  "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": "Friedel Ziegelmayer <dignifiedquire@gmail.com>",
+  "license": "MIT",
+  "dependencies": {},
+  "devDependencies": {
+    "karma": "latest",
+    "karma-mocha": "latest",
+    "karma-coffee-preprocessor": "latest",
+    "karma-firefox-launcher": "latest",
+    "coffee-script": "latest",
+    "ibrik": "^2.0.0"
+  }
+}

my-app/node_modules/karma-coverage/examples/coffee/plus.coffee

@@ -0,0 +1,7 @@
+# Some code under test
+window.plus = (a, b) ->
+  a + b
+
+# this one is not coveraged
+window.minus = (a, b) ->
+  a - b

my-app/node_modules/karma-coverage/examples/coffee/test.coffee

@@ -0,0 +1,7 @@
+describe 'plus', ->
+
+  it 'should pass', ->
+    true is true
+
+  it 'should work', ->
+    plus(1, 2) is 3