add-unit-tests

You are writing missing unit tests for a makeup-js module. Your goal is to fill coverage gaps with well-structured tests that follow the existing conventions — not to rewrite existing tests or pad coverage with low-value assertions.

Input

The user will provide a module name (e.g., "makeup-next-id" or full path like "packages/core/makeup-next-id"). Optionally, the user may paste a gap report from /test-coverage — if so, use it to skip re-running coverage and go straight to writing.

Process

1. Locate the module

• Find the module in packages/core/ or packages/ui/
• Read src/index.js (or all files in src/)
• Read test/index.js (or all files in test/)

2. Identify gaps

If the user did not provide a gap report, run coverage to find them:

npm run test:coverage -- --coverage.include="packages/core/<module-name>/src/**" packages/core/<module-name>

Read the source and tests side by side to identify:

• Uncovered branches (if/else, ternaries, ?., ??)
• Uncovered functions
• Missing edge cases (empty input, boundary values, error conditions)
• Missing negative cases (invalid input that is guarded in code)

Skip gaps that are not worth testing (non-deterministic internals, unreachable defensive guards, browser-only paths that jsdom cannot exercise).

3. Write the tests

Append the new tests to test/index.js. Do not modify existing tests.

Follow the existing conventions exactly:

• BDD structure: describe("given X") > describe("when Y") > it("should Z")
• One assertion per it block where practical
• Use beforeEach/beforeAll for setup, matching the pattern already in the file
• Use vi.spyOn() for mocking, vi.useFakeTimers() for timers — restore in afterEach
• Import only what is needed; do not add imports already present at the top of the file
• Match the indentation and formatting of the existing file

4. Run and verify

Run the tests to confirm they pass:

npm run test:unit -- packages/core/<module-name>

If any test fails, fix it before proceeding. Do not leave failing tests.

Then re-run coverage to confirm the gaps are closed:

npm run test:coverage -- --coverage.include="packages/core/<module-name>/src/**" packages/core/<module-name>

5. Summary

Report:

• Which gaps were addressed and which were intentionally skipped (and why)
• Updated coverage numbers
• Number of tests added