Testing Tools.

Testing frameworks, runners, and utilities. Covers 10 sub-skills.

• Testing Tools · 1 of 3

  Jest

  Which Jest lifecycle hook runs before every test in its enclosing describe block?

  AbeforeEach()BbeforeAll()CbeforeSuite()DafterEach()

• Testing Tools · 2 of 3

  Testcontainers

  Why configure explicit wait strategies in Testcontainers?

  AEnsure service readiness before testsBReduce container startup time to minimumCAvoid port conflicts between containersDEnable parallel test execution safely

• Testing Tools · 3 of 3

  Mock Service Worker (MSW)

  Why should CI fail on unexpected unmocked network requests with MSW?

  AThey give you contract coverage against the live API for freeBAllowing them keeps the mock surface area small over timeCDetects drift and unintended backend couplingDUnmocked calls reach the real backend, raising fidelity