@netflix/x-test

x-test

a simple, tap-compliant test runner for the browser

Spec

• importable as type="module"
• is interoperable with TAP Version 14
• nested sub-tests run in an iframe
• has a recognizable testing interface (it, describe, assert)
• can be used for automated testing
• can be used to assert coverage goals

Interface

Testing

The following are exposed in the testing interface:

• test: Creates a sub-test in an iframe based on given src html page.
• it: The smallest testing unit — can be asynchronous.
• it.skip: An it whose callback is not run and which will pass.
• it.only: Skip all other it tests.
• it.todo: An it whose callback is run and is expected to fail.
• describe: Simple grouping functionality.
• describe.skip: Skip all it tests in this group.
• describe.only: Skip all other describe groups and it tests.
• describe.todo: Mark all it tests within this group as todo.
• waitFor: Ensures test registration remains open until given promise settles.
• assert: Simple assertion call that throws if the boolean input is false-y.
• coverage: Sets a coverage goal for the given href.

Events

Messages are posted to a BroadcastChannel channel with the name x-test.

• x-test-client-ping: root responds (x-test-root-pong, { status: 'started'|'ended' waiting: true|false })
• x-test-root-pong: response to x-test-client-ping
• x-test-root-coverage-request: client should respond (x-test-coverage-result)
• x-test-client-coverage-result: response to x-test-root-coverage-request
• x-test-root-end: all tests have completed or we bailed out
• (internal) x-test-root-run: all tests have completed or we bailed out
• (internal) x-test-suite-coverage: signal to test for coverage on a particular file
• (internal) x-test-suite-register: registers a new test / describe / it
• (internal) x-test-suite-ready: signal that test suite is done with registration
• (internal) x-test-suite-result: marks end of "it" test
• (internal) x-test-suite-bail: signal to quit test early

Parameters

The following parameters can be passed in via query params on the url:

• x-test-no-reporter: turns off custom reporting tool ui
• x-test-run-coverage: turns on coverage reporting**
• x-test-name: filters tests by name using regex pattern matching

**See Command Line Usage.

Execution

Both test and it calls will execute in order**. test calls will boot the given html page in an iframe. Such iframes are run one-at-a-time. All invoked it calls await the completion of previously-invoked it calls.

**This is not the case if you nest it--but that's an anti-pattern anyhow.

Test Filtering

You can filter tests by name using the x-test-name query parameter, which accepts a regex pattern. This allows you to run only specific tests that match the pattern.

Browser Usage

http://localhost:8080/test/?x-test-name=should%20validate

Command Line Usage

For automated testing with a Node.js CLI, see the @netflix/x-test-cli package documentation.

Parsing TAP

There are many TAP formatters. Importantly, as long as you can pipe the TAP output to another program, the output should be interoperable.