Karma-coverage not found: But, it is installed - angularjs

Question

I used this guide http://karma-runner.github.io/0.8/config/coverage.html to setup my Karma-coverage plugin. Furthermore, it gets installed locally via the package.json file, which looks like this:
{
"name": "myApp",
"version": "0.1.0",
"devDependencies": {
"karma-jasmine": "latest",
"karma-coverage": "latest",
"karma-coffee-preprocessor": "latest",
"karma-chrome-launcher": "latest",
"coffee-script": "latest"
}
}
My Karma.conf looks like this:
// Karma configuration
// Generated on Sun Dec 07 2014 15:51:07 GMT+0100 (CET)
module.exports = function(config) {
config.set({
// base path that will be used to resolve all patterns (eg. files, exclude)
basePath: '',
// frameworks to use
// available frameworks: https://npmjs.org/browse/keyword/karma-adapter
frameworks: ['jasmine'],
// list of files / patterns to load in the browser
files: [
'javascripts/vendor/jquery_211.js',
'javascripts/vendor/angular.js',
'javascripts/vendor/angular-route.js',
'javascripts/vendor/angular-mocks.js',
'../app/assets/javascripts/app.coffee',
'javascripts/*.js',
'test/controllers/*.js'
],
// list of files to exclude
exclude: [
],
// preprocess matching files before serving them to the browser
// available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
preprocessors: {
'../app/assets/javascripts/app.coffee' : ['coffee'],
'**/javascripts/*.js': 'coverage'
//'**/*.coffee': ['coffee']
},
// test results reporter to use
// possible values: 'dots', 'progress'
// available reporters: https://npmjs.org/browse/keyword/karma-reporter
reporters: ['progress', 'coverage'],
// web server port
port: 9876,
// enable / disable colors in the output (reporters and logs)
colors: true,
// level of logging
// possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
logLevel: config.LOG_INFO,
// enable / disable watching file and executing tests whenever any file changes
autoWatch: true,
// start these browsers
// available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
browsers: ['Chrome'],
// Continuous Integration mode
// if true, Karma captures browsers, runs the tests and exits
singleRun: false
});
};
Now, while running karma I receive the error
WARN [reporter]: Can not load "coverage", it is not registered!
Perhaps you are missing some plugin?
INFO [karma]: Karma v0.12.28 server started at http://localhost:9876/
INFO [launcher]: Starting browser Chrome
WARN [preprocess]: Can not load "coverage", it is not registered!
Perhaps you are missing some plugin?
It does not matter, if I include karma-coverage in the plugin section of the karma.conf file, the problem stays the same (since the plugin gets loaded locally, I should not need the plugin part anyway...). I hope somebody of you guys has an idea... Thank you!

Answer 1

npm install -g karma-coverage to install the karma-coverage, and it will work fine, but i don't know why.
// Karma configuration
// Generated on Tue Oct 13 2015 11:14:07 GMT+0800 (CST)
module.exports = function(config) {
config.set({
// base path that will be used to resolve all patterns (eg. files, exclude)
basePath: '',
// frameworks to use
// available frameworks: https://npmjs.org/browse/keyword/karma-adapter
frameworks: ['jasmine'],
// list of files / patterns to load in the browser
files: [
'*.js'
],
// list of files to exclude
exclude: [
'karma.config.js'
],
// preprocess matching files before serving them to the browser
// available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
preprocessors: {
'*.js': 'coverage'
},
coverageReporter:{
type: 'html',
dir: './coverage'
},
// test results reporter to use
// possible values: 'dots', 'progress'
// available reporters: https://npmjs.org/browse/keyword/karma-reporter
reporters: ['progress','coverage'],
// web server port
port: 9876,
// enable / disable colors in the output (reporters and logs)
colors: true,
// level of logging
// possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
logLevel: config.LOG_INFO,
// enable / disable watching file and executing tests whenever any file changes
autoWatch: true,
// start these browsers
// available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
browsers: ['Chrome'],
// Continuous Integration mode
// if true, Karma captures browsers, runs the tests and exits
singleRun: false
})
}

Answer 2

The solution for this problem was that I had a couple of installed node_modules within my users home folder. After deinstalling these modules and the locally installed ones via npm, I made a clean reinstall via npm link. This solved the problem for me!

Answer 3

plugins: [
require('karma-jasmine'),
require('karma-coverage'),
require('karma-chrome-launcher'),
require('karma-jasmine-html-reporter'),
require('karma-coverage-istanbul-reporter'),
require('#angular-devkit/build-angular/plugins/karma')
],
After added **"karma-coverage"** into the plugins array in karma.conf.js
it works to me. Thanks