testing-server-actions

Testing Server Actions in React 19 involves writing isolated unit tests using Vitest to verify server-side logic, input validation, and expected outcomes. Mock database calls and external dependencies to test the action logic in isolation without hitting real services.

Use Vitest mocking patterns to replace database interactions with test doubles. Mock the database module or client before each test, define expected return values, and verify the action calls the database correctly with the right parameters.

Yes. Create FormData objects in tests, pass them to Server Actions, and assert that the action validates inputs correctly and handles both valid and invalid submissions. Test templates show how to construct FormData and verify success or error results.

Mock authentication context or user session state, then test that Server Actions enforce permission rules. Write separate test cases for authorized and unauthorized access attempts to ensure the action rejects requests appropriately.

Test input validation, authorization checks, database operations, and error handling. Verify that valid inputs produce expected outcomes, invalid inputs are rejected, unauthorized users cannot execute the action, and errors are handled gracefully.

Isolated testing ensures Server Actions enforce data integrity and security rules correctly without relying on external systems. This catches bugs in critical server-side logic early and prevents unauthorized access or data corruption in production.