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Code coverage for ember apps using Istanbul
Code coverage using Istanbul for Ember apps.
>= 1.6.0 for which you need ember-cli > 2.4.3ember-cli-mirage >= 0.1.13pretender >= 0.11.0ember-cli-babel >= 6.0.0ember install ember-cli-code-coverageIn order to gather code coverage information, you must first install the Babel plugins in each project that you'd like to have instrumented.
For classic apps (ember-cli-build.js):
let app = new EmberApp(defaults, { babel: { plugins: [...require('ember-cli-code-coverage').buildBabelPlugin()], }, });
For embroider apps (ember-cli-build.js):
let app = new EmberApp(defaults, { babel: { plugins: [...require('ember-cli-code-coverage').buildBabelPlugin({ embroider: true })], }, });
For in-repo and standalone addons (index.js):
module.exports = { name: require('./package').name, options: { babel: { plugins: [...require('ember-cli-code-coverage').buildBabelPlugin()], }, }, };
For in-repo engines (index.js):
module.exports = EngineAddon.extend({ // ... included() { this._super.included.apply(this, arguments); this.options.babel.plugins.push(...require('ember-cli-code-coverage').buildBabelPlugin()); }, });
For app files in standalone addons (ember-cli-build.js):
let app = new EmberAddon(defaults, { babel: { plugins: [...require('ember-cli-code-coverage').buildBabelPlugin()] }, });
tests/test-helpers.js:
import { forceModulesToBeLoaded, sendCoverage } from 'ember-cli-code-coverage/test-support'; import Qunit from 'qunit'; QUnit.done(async function() { forceModulesToBeLoaded(); await sendCoverage(); });
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.
If you intend to use ember test with the --path flag, you should generate the build
with coverageEnvVar set as true. This is because the code is instrumented for
coverage during the build.
For example:
COVERAGE=true ember build --environment=test --output-path=dist
followed by
COVERAGE=true ember test --path=dist
Steps:
tsconfig.json{ "compilerOptions": { "inlineSourceMap": true, "inlineSources": true } }
ember-cli-build.jsconst app = new EmberApp(defaults, { babel: { sourceMaps: 'inline' }, sourcemaps: { enabled: true, extensions: ['js'] } });
package.json specify latest available version{ devDependencies: { "ember-cli-code-coverage": "^2.1.0", } }
const app = new EmberApp(defaults, {
'ember-template-imports': {
inline_source_map: true,
},
});
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.
Reporters can be configured with array-style syntax, for example, here are
options to lcov with a different projectRoot: [['lcov', { projectRoot: '/packages/addon' }], 'html']
excludes: Defaults to ['*/mirage/**/*']. An array of globs to exclude from instrumentation. Useful to exclude files from coverage statistics.
extension: Defaults to ['.gjs', '.gts', '.js', '.ts', '.cjs', '.mjs', '.mts', '.cts']. Tell Istanbul to instrument only files with the provided extensions.
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).
modifyAssetLocation: Optional function that will allow you to override where a file actually lives inside of your project. See Advanced customization on how to use this function in practice.
module.exports = { coverageEnvVar: 'COV' }
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);
});
The forceModulesToBeLoaded function can potentially cause unintended side effects when executed. You can pass custom filter fuctions that allow
you to specify which modules will be force loaded or not:
QUnit.done(async () => { // type will be either webpack and/or require forceModulesToBeLoaded((type, moduleName) => { return true; }); await sendCoverage(); });
Under the hood, ember-cli-code-coverage attempts to "de-namespacify" paths into their real on disk location inside of
project.root (ie give a namespaced path like lib/inrepo/components/foo.js would live in lib/inrepo/addon/components/foo.js). It makes
some assumptions (where files live in in-repo addons vs app code for example) and sometimes those assumptions might not hold. Passing a
function modifyAssetLocation in your configuration file will allow you to override where a file actually lives inside
of your project. The returned string should be relative to your project root.
module.exports = { modifyAssetLocation(root, relativePath) { let appPath = relativePath.replace('my-project-name', 'app'); // here is an example of saying that `app/components/foo.js` actually // lives in `lib/inrepo/app/components/foo.js` on disk. if (fs.existsSync(path.join(root, 'lib', 'inrepo', appPath))) { return path.join('lib', 'inrepo', appPath); } return false; }, };
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.