A test that had passed ten thousand times serially and failed roughly one run in twelve once eight processes shared a clock. Serial execution made the timing deterministic…
A test that filled a form, submitted it and asserted on the resulting page, which passed when the redirect went somewhere wrong. Asserting on a page’s content without…
Tests describing what a consumer reads, written by them, run by us. Owning the tests ourselves means asserting what we intended, and the risk is the gap between…
Eight parallel processes, and one test group that writes to a fixed path on disk. Two runs — parallel for everything and serial for the exceptions — is…
Parallel test processes sharing one database, and the transaction-per-test isolation that stops working under concurrency. Loading the schema from a dump rather than migrating is what makes eight…