Are tests inside a single file parallel in Jest?

Question

Jest state in docs: "Jest virtualizes JavaScript environments and runs tests in parallel between workflows."

But what about multiple tests within a single file, are they executed in parallel, or is this statement only applied to test files? Can I assume that the tests in one file are performed in order of appearance and in serial?

Answer 1

Yes, you can safely assume that the tests inside the same file will work in the order they appear. You can prove this by putting console.log in every it block.

It might be worth mentioning that it’s generally bad practice to rely on the execution order / external state ... and you never know, Jest (or the current base tester, Jasmine) may decide to run them randomly in a newer version.