Single test runner

How to add a new test file

The single test runner supports automatic test discovery. We only need to put a test file into a test subfolder, next to the files we want to test. The runner uses this glob pattern @(client|server|test)/**/test/*.@(js|jsx) to find test files.

We should use the same file names as the implementation files for the tests. Example: if we want to write unit tests covering the file hello-world/index.jsx, we should name a test file hello-world/test/index.jsx.

If we ever need to add non-test files to a test folder, we should put them in a deeper level. Common choices are:

• test/mocks/name.js for test mocks
• test/fixtures/name.js for test data

How to run single test runner

Executing make test from the root folder will run all test suites. Behind the scenes we maintain 3 test runners. This is because each folder (client, server & test) has a different NODE_PATH path.

We have also an npm run script for each folder: npm run test-client, npm run test-server and npm run test-test. We can pass a filename or set of files to these scripts to isolate your test run to a selected set of files.

Example for client:

> # run the entire client suite
> npm run test-client
> # if you want to use different test reporter
> npm run test-client -- --reporter=dot #notice the -- separating out the params to pass to the runner
> # runner knows about Mocha --grep flag
> npm run test-client -- --grep "state ui" # to just run the state/ui tests
> # run single test suite from server folder
> npm run test-server server/config/test/parser.js
> # run single test suite from test folder
> npm run test-test test/helpers/use-nock/test/index.js
> # run test suite for all files in a specific folder
> npm run test-client client/state
> npm run test-client client/state/posts/test

How to run specified suite or test-case

The exclusivity feature allows you to run only the specified suite or test-case by appending .only() to the function. It works with describe and it functions. More details in Mocha documentation.

Using only is a little bit dangerous, as you may end up committing the only, which would cause the test suite to only run your test on the build server. So be sure to look for stray only calls when reviewing a test. We have an eslint rule in the works that should catch them for you.

Example:

describe.only( 'just run this suite', function() {
	it( 'should run these tests', function() {
		// your test
	} );

	it.only( 'should only run this one test', function() {
		// just run this test if the only is present
	} );
} );

How to run Mocha directly

You can run Mocha directly by using run-mocha.js as the entry point for Mocha. Note that this only works for tests inside single test runner. This gives you more flexibility to integrate with different toolings.

Example:

# Run all client tests within the single test runner
$ NODE_ENV=test NODE_PATH=client:test node_modules/.bin/mocha test/run-mocha.js 

# Run all server tests within the single test runner
$ NODE_ENV=test NODE_PATH=server:client:test node_modules/.bin/mocha test/run-mocha.js