angular-cn/aio/content/guide/test-debugging.md

Debugging tests

If your tests aren't working as you expect them to, you can inspect and debug them in the browser.

Debug specs in the browser in the same way that you debug an application.

1. Reveal the Karma browser window. See Set up testing if you need help with this step.
2. Click the DEBUG button; it opens a new browser tab and re-runs the tests.
3. Open the browser's “Developer Tools” (Ctrl-Shift-I on Windows; Command-Option-I in macOS).
4. Pick the "sources" section.
5. Open the 1st.spec.ts test file (Control/Command-P, then start typing the name of the file).
6. Set a breakpoint in the test.
7. Refresh the browser, and it stops at the breakpoint.