Want to increase quality of testing? Empower yourself with test pyramid (triangle)!
What testing on different layers means? How many tests do you need on each level? Why can't you test everything on the UI level? Many reasons, mainly the time and brittleness of tests.
We look at the example of a simple website (HTML+JS) having a backend API (Node.js/Express) and a database. We highlight the fragility and slowness of the E2E (or end-to-end) tests and compare them to the unit and integration tests. Many testers (and organisations) think that it's a job of a developer to write unit tests, but the tester should write system-level tests. It often leads to a lot of brittle test abominations. You will never have a good test automation suite that helps everybody to ship software faster.
What to do instead? You need to test:
the units
their integration between each other
the behaviour of the whole system after connecting all parts
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---------- Timeline -------------------------------------------------------------------
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0:00 - intro
0:20 - architecture of the system
0:40 - what is the test pyramid?
1:55 - UI overview
3:05 - adding first bricks
4:55 - unit testing on the UI layer
7:10 - testing the API
7:45 - business logic and database layer tests
9:36 - static analysis, linting
10:40 - why do we need it?