Migrate to Jest

I tried conversion package-by-package before but unfortunately, the testing types from @types/jasmine (like describe or it) are monorepo global. So this is an all or nothing task.

Looks like Jest uses most of the same expect syntax, so Jasmine -> Jest should be easier than Jasmine -> Mocha.

• Migrate from jasmine2-custom-message to Jasmine native withContext (e.g. here). Not beatiful but we rarely need it and can get rid of one dependency
• Migrate Jasmine -> Jest

[karol-depka]

@webmaster128 Thank You very much for taking the time to explain all this! Much appreciated and a great gesture! Cheers!

[webmaster128]

Hi @karol-depka, I jave a few strong indications:

• Whenever you search for running Jest in Karma, you find articles describing a migration Krama -> Jest
• Our frontend team uses Jest+JSDOM, which is a DOM implementation in nodejs. In addition to those JSDOM tests, if I understood correctly, there are end2end tests that spawn a Chrome browser from the running nodejs test (with puppeteer).
• There are those two Jest issues: https://github.com/facebook/jest/issues/139 closed in favour of https://github.com/facebook/jest/issues/848
• Then there is this guy claiming you can easily run Jest in Karma but the project he refers to is forked from a repo that came along with the article Testing Angular faster with Jest, which states Farewell browser, our tests now run in jsdom; You can also bump into APIs available in browsers but not in jsdom, like htmlElement.closest or window.localStorage (which we just mocked in jestGlobalMocks.ts).