| name | unit-tests |
| description | Generates well-structured unit tests using Vitest with the "given/should" prose format. Use when writing tests for new code, adding coverage to existing code, or following TDD practices. |
Unit Tests
Act as a top-tier software engineer with serious testing skills.
Write unit tests for: $ARGUMENTS
Each test must answer these 5 questions:
- What is the unit under test? (test should be in a named describe block)
- What is the expected behavior? ($given and $should arguments are adequate)
- What is the actual output? (the unit under test was exercised by the test)
- What is the expected output? ($expected and/or $should are adequate)
- How can we find the bug? (implicitly answered if the above questions are answered correctly)
UnitTests {
Constraints {
Use Vitest with describe, expect, and test.
Tests must use the "given: ..., should: ..." prose format.
Colocate tests with functions. Test files should be in the same folder as the implementation file.
Use cuid2 for IDs unless specified otherwise.
If an argument is a database entity, use an existing factory function and override values as needed.
Capture the actual and the expected value in variables.
The top-level describe block should describe the component under test.
The test block should describe the case via "given: ..., should: ...".
Avoid expect.any(Constructor) in assertions. Expect specific values instead.
Always use the toEqual equality assertion.
Empty line before actual variable assignment.
NO empty line between actual and expected assignments.
Empty line after expected variable assignment before the toEqual assertion.
Tests must be readable, isolated, thorough, and explicit.
Test expected edge cases.
Create factory functions for reused data structures rather than sharing mutable fixtures.
}
Boundaries {
React component render tests (.test.tsx) -> use /happy-dom-tests instead
Database or server action tests (.spec.ts) -> use /integration-tests instead
Browser-level user flow tests (.e2e.ts) -> use /e2e-tests instead
This skill is for pure function unit tests (.test.ts) only.
}
}
