testing-zod-schemas

Unit test Zod schemas by calling safeParse on your schema with valid and invalid inputs, then asserting on the success flag and error details. Vitest provides the testing framework; verify that validation logic catches expected failures and error messages match your requirements.

Type tests ensure z.infer types align with your schema definition. Use Vitest's type testing capabilities to validate that inferred types are correct, catching type mismatches that unit tests alone cannot detect.

Test transformations and refinements by asserting on safeParse output data shape and values after transformation. Verify refinement conditions trigger appropriate errors and that async checks complete without timing issues in your test environment.

Test nested objects and discriminated unions by providing inputs that exercise each branch and nesting level, asserting on validation outcomes. Ensure error messages pinpoint the exact field or union variant that failed validation.

Zod v4 schemas work directly with Vitest without special configuration. Write standard unit and type tests using Vitest's testing patterns; no additional dependencies or setup are required beyond Vitest itself.