effect-testing

You can test Effect-based code deterministically by using TestClock for time-sensitive effects and layered test composition to control execution flow. This ensures reliable outcomes across complex workflows without waiting for actual time to pass.

Yes, property-based testing is supported with Effect and Vitest through the @effect/vitest package. This allows you to generate diverse inputs automatically, ensuring your Effect-based applications handle a wide range of edge cases robustly.

The best way to mock external services in Effect tests is by using safe mocking patterns and effect layers. This approach allows you to isolate dependencies and simulate external service behaviors, including AI prompt responses, reliably.

You can run integration tests for Effect apps using testcontainers to validate database interactions in an isolated environment. This validates your application's database interactions against real instances without affecting your production data.

Yes, this Skill supports testing complex workflows through layered test composition and reusable test helpers with effect layers. This allows you to build up test scenarios modularly, ensuring each layer of your application is validated correctly.

Time-sensitive Effect tests often fail intermittently due to non-deterministic timing. Using TestClock resolves this by providing deterministic timing, allowing you to control and advance time manually in your tests for reliable execution.