ember-cli-code-coverage

Code coverage using Istanbul for Ember apps.

• If using Mocha, Testem >= 1.6.0 for which you need ember-cli > 2.4.3
• If using Mirage you need ember-cli-mirage >= 0.1.13
• If using Pretender (even as a dependency of Mirage) you need pretender >= 0.11.0
• If using Mirage or Pretender, you need to set up a passthrough for coverage to be written.
• ember-cli-babel >= 6.0.0

• ember install ember-cli-code-coverage

Coverage will only be generated when an environment variable is true (by default COVERAGE) and running your test command like normal.

For example:

COVERAGE=true ember test

If you want your coverage to work on both Unix and Windows, you can do this:

npm install cross-env --save-dev

and then:

cross-env COVERAGE=true ember test

When running with parallel set to true, the final reports can be merged by using ember coverage-merge. The final merged output will be stored in the coverageFolder.

Configuration is optional. It should be put in a file at config/coverage.js (configPath configuration in package.json is honored). In addition to this you can configure Istanbul by adding a .istanbul.yml file to the root directory of your app (See https://github.com/gotwarlost/istanbul#configuring)

• coverageEnvVar: Defaults to COVERAGE. This is the environment variable that when set will cause coverage metrics to be generated.

• reporters: Defaults to ['lcov', 'html']. The json-summary reporter will be added to anything set here, it is required. This can be any reporters supported by Istanbul.

• excludes: Defaults to ['*/mirage/**/*']. An array of globs to exclude from instrumentation. Useful to exclude files from coverage statistics.

• coverageFolder: Defaults to coverage. A folder relative to the root of your project to store coverage results.

• parallel: Defaults to false. Should be set to true if parallel testing is being used for separate test runs, for example when using ember-exam with the --partition flag. This will generate the coverage reports in directories suffixed with _<random_string> to avoid overwriting other threads reports. These reports can be joined by using the ember coverage-merge command (potentially as part of the posttest hook in your package.json).

  module.exports = {
    coverageEnvVar: 'COV'
  }

To analyze coverage stats you will need the nyc command line tool. The first step is to install it:

npm install nyc --save-dev

Then you will need to define the thresholds you would like by adding a .nycrc file to the root of your app.

For example:

{
  "all": true,
  "check-coverage": true,
  "per-file": true,
  "temp-directory": "coverage",
  "branches": 60,
  "functions": 60,
  "lines": 60,
  "statements": 60,
  "watermarks": {
    "branches": [70, 80],
    "functions": [70, 80],
    "lines": [70, 80],
    "statements": [70, 80]
  }
}

With this config, nyc will validate the coverage percentage for each file individually and fail whenever it’s lower than 60%. The watermarks numbers are used only as guidelines to modify the output color of the reporter.

Next, to execute nyc you can define a command to check the coverage in package.json:

"scripts": {
  "test": "COVERAGE=true ember test",
  "check-coverage": "./node_modules/.bin/nyc check-coverage"
}

Finally, to fail the build on Travis if the thresholds are not met, you can add the previously defined command in the "script" section:

script:
  - npm test
  - npm run check-coverage

To work, this addon has to post coverage results back to a middleware at /write-coverage.

If you are using ember-cli-mirage you should add the following:

// in mirage/config.js

  this.passthrough('/write-coverage');
  this.namespace = 'api';  // It's important that the passthrough for coverage is before the namespace, otherwise it will be prefixed.

If you are using ember-cli-pretender you should add the following:

// where ever you set up the Pretender Server

  var server = new Pretender(function () {
    this.post('/write-coverage', this.passthrough);
  });

This addon was inspired by ember-cli-blanket. The primary differences are that this addon uses Istanbul rather than Blanket for coverage and it instruments your application code as part of the build, when enabled.