README.md

Testing Angular at Hetzner

Slides for the mentioned e2e testing presentation: https://wachri.github.io/protractor-e2e-testing

jasmine and karma come out of the box and are easy to use
but they are slow and have a lot of overhead
karma can run against multiple browsers
Jest only compiles what is needed
no endless startup time for jest
can run tests in parallel
snapshot test can be very helpful for component tests -> match snapshots for the html
but the snapshots are often hard to maintain. Especially with larger component it might not be useful. So good for "lazy tests" but nothing complex
proposed alternative to snapshots from the audience: enzyme
angular support: jest-preset-angular
migrating tool: jest-codemods
but : spying system is different
hetzner developed jasmine polyfill but sadly not open source yet.
this polyfill allows running the jest tests with karma as well
snapshot tests can not run in the karma test suite

limit the usage of fixture.detectchanges() to only after everything is set up
don't import modules, declare components
eliminate template in unit tests
ngx-prepare-test-environment -> on npm
find slow tests manually. There might individual tests that slow your whole suite down.

jest swallows async thrown exceptions which then show up in karma later on
browser animations and snapshot tests -> angular animation magic has strange side effects on other components
.tothrow does not do a deep equal
not all browser Api's are available in the virtual Dom which you then have to mock for snapshot test