See CLAUDE.md for terminology and the "where should I put my test?" decision table. Quick map:
- Unit tests
- Vitest -- next to source in
src/vs/. - Core Mocha -- upstream VS Code's Mocha suite, in
unit/.
- Vitest -- next to source in
- Extension host tests --
integration/(VS Code historically calls these "integration tests"). - E2E tests --
e2e/(Playwright).