Run Unit Tests

Test Skill

Use the following commands to run unit tests for the Cosmos Explorer project.

Pre-Test: Check Dependencies

Before running tests, check whether npm install needs to be run:

if [ ! -d node_modules ] || [ package.json -nt node_modules ] || [ package-lock.json -nt node_modules ]; then
  npm install
fi

On Windows PowerShell:

if (-not (Test-Path node_modules) -or
    (Get-Item package.json).LastWriteTime -gt (Get-Item node_modules).LastWriteTime -or
    (Get-Item package-lock.json).LastWriteTime -gt (Get-Item node_modules).LastWriteTime) {
    npm install
}

Always run this check before proceeding with any test command.

Run All Unit Tests

Run the full test suite with coverage:

npm test

This clears the coverage/ directory and runs Jest with coverage collection enabled.

Run a Single Test File

Run a specific test file without coverage (faster):

npm run test:file -- path/to/file.test.ts

Run Tests in Debug Mode

Run tests serially (useful for debugging flaky or interdependent tests):

npm run test:debug

Run Tests Matching a Pattern

Run only tests whose names match a pattern:

npx jest --coverage=false --testPathPattern="SomeComponent"

Guidelines

• When asked to simply "run tests" or "test", run npm test for the full suite.
• When asked to test a specific file or component, use npm run test:file -- <path>.
• When debugging test failures, use npm run test:debug to run serially.
• Unit test files live adjacent to source files (Foo.test.ts next to Foo.ts in src/).
• Tests use Jest with jest-environment-jsdom.
• Use @testing-library/react for new component tests. Do not use Enzyme for new tests.
• Use Jest built-in mocking, not sinon.js.
• Coverage thresholds are enforced globally: branches 25%, functions 24%, lines 28%, statements 28%.
• If tests fail, read the error output carefully. Common issues include:
  • Snapshot mismatches: Review the diff. If the change is intentional, update snapshots with npx jest --updateSnapshot.
  • Mock issues: Ensure mocks are set up correctly and reset between tests.
  • Import errors: Check that module name mappings in jest.config.js are correct.
  • Type errors in tests: Run npm run compile to check for TypeScript issues.

Source: Azure/cosmos-explorer — distributed by TomeVault.