Proof of concept for implementing frontend integration tests

The frontend testing guide mentions frontend integration tests as a testing level between unit tests and system tests (spec/features/).

In Karma the distinction between frontend integration tests and unit tests is not clear and we have not framework that supports the former. Additionally we are aiming at migrating all Karma tests to Jest (&895 (closed)).

In Jest we are currently running all tests in JSDOM and not in a browser. This implies that certain scenarios cannot be tested or behave differently than in the real application. Additionally Jest does not provide a framework for integration level tests either.

This issue is meant to evaluate our options by implementing a proof of concept for frontend integration tests.

Old description

Support running Jest tests in browsers

Our Jest tests currently run with jsdom which is the default. We should look into ways to also make it run in real browsers.

See also

• https://github.com/smooth-code/jest-puppeteer
• https://github.com/GoogleChrome/puppeteer/tree/master/experimental/puppeteer-firefox/

This issues is meant to provide a proof of concept. We can then create follow-up issues for the implementation if necessary.