Rather than use our own custom expect library, we can use expect from npm [1], which has an API almost identical to the one Puppeteer has, but with more options, better diffing, and is used by many in the community as it's the default assertions library that comes with Jest.
It's also thoroughly documented [2].
[1]: https://www.npmjs.com/package/expect
[2]: https://jestjs.io/docs/en/expect
`testRunner.run()` might have 4 different outcomes:
- `ok` - all non-skipped tests passed
- `failed` - some tests failed or timed out
- `terminated` - process received SIGHUP/SIGINT while testrunner was running tests. This happens on CI's under certain circumstances, e.g. when
VM is getting re-scheduled.
- `crashed` - testrunner terminated test execution due to either `UnhandledPromiseRejection` or
some of the hooks (`beforeEach/afterEach/beforeAll/afterAll`) failures.
As an implication, there are 2 new test results: `terminated` and `crashed`.
All possible test results are:
- `ok` - test worked just fine
- `skipped` - test was skipped with `xit`
- `timedout` - test timed out
- `failed` - test threw an exception while running
- `terminated` - testrunner got terminated while running this test
- `crashed` - some `beforeEach` / `afterEach` hook corresponding to this
test timed out of threw an exception.
This patch changes a few parts of the testrunner API:
- `testRunner.run()` now returns an object `{result: string,
terminationError?: Error, terminationMessage?: string}`
- the same object is dispatched via `testRunner.on('finished')` event
- `testRunner.on('terminated')` got removed
- tests now might have `crashed` and `terminated` results
- `testRunner.on('teststarted')` dispatched before running all related
`beforeEach` hooks, and `testRunner.on('testfinished')` dispatched after
running all related `afterEach` hooks.
