Unable to run Coverage with Karma

Question

I'm trying to run coverage with karma, and I get the warning: WARN [preprocess]: Can not load "coverage", it is not registered!

I thought I installed coverage when I ran 'npm install -g karma-coverage --save-dev'

Here's my config file:

module.exports = function(config) {       config.set({         // base path, that will be used to resolve files and exclude         basePath: '',          frameworks: ['jasmine'],          // list of files / patterns to load in the browser         files: [                 bunch of files..         ],          // list of files to exclude         exclude: [],          // use dots reporter, as travis terminal does not support escaping sequences         // possible values: 'dots', 'progress'         // CLI --reporters progress         reporters: ['progress', 'coverage'],          junitReporter: {           // will be resolved to basePath (in the same way as files/exclude patterns)           outputFile: 'test-results.xml'         },          // web server port         // CLI --port 9876         port: 9876,          // enable / disable colors in the output (reporters and logs)         // CLI --colors --no-colors         colors: true,          // level of logging         // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG         // CLI --log-level debug         logLevel: config.LOG_INFO,          // enable / disable watching file and executing tests whenever any file changes         // CLI --auto-watch --no-auto-watch         autoWatch: true,          // Start these browsers, currently available:         // - Chrome         // - ChromeCanary         // - Firefox         // - Opera         // - Safari (only Mac)         // - PhantomJS         // - IE (only Windows)         // CLI --browsers Chrome,Firefox,Safari         browsers: ['ChromeCanary'],          // If browser does not capture in given timeout [ms], kill it         // CLI --capture-timeout 5000         captureTimeout: 20000,          // Auto run tests on start (when browsers are captured) and exit         // CLI --single-run --no-single-run         singleRun: true,          // report which specs are slower than 500ms         // CLI --report-slower-than 500         reportSlowerThan: 500,          // compile coffee scripts         preprocessors: {             'someFileName': ['coverage'],         },          plugins: [           'karma-jasmine',           'karma-chrome-launcher',           'karma-firefox-launcher',         ],      coverageReporter: {         'type' : 'cobertura',         'dir': 'coverage/'     }    }); }; 

Answer 1

I got the same [WARN] because the plugin 'karma-coverage' was not defined inside the plugins of the config, try to see if adding it fixes your warning, not sure if it will fix your full problem.

plugins: [   'karma-jasmine',   'karma-coverage',   'karma-chrome-launcher',   'karma-firefox-launcher', ], 

UPDATE:
I also had a different problem when running the coverage, caused by istanbul, my error was

[coverage]: [TypeError: Cannot set property 'covered' of undefined]

After having a look what istanbul was doing it turned out that the paths to some of my js unit files were outdated in the preprocessors.

It was doing some of the coverage reports but it was not generating deep coverage reports for all files hence the error. Once I fixed the paths it was all good.

    preprocessors : {         '**/app/js/*/*.js' : 'coverage',         '**/app/js/modules/*/*.js' : 'coverage',         '**/app/js/services/*/*.js' : 'coverage'     },