docs: traducir guide/test-debugging (#262)

aio/content/guide/test-debugging.en.md

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+# Debugging tests
+
+If your tests aren't working as you expect them to, you can inspect and debug them in the browser.
+
+<div class="alert is-helpful">
+
+  For the sample app that the testing guides describe, see the <live-example name="testing" embedded-style noDownload>sample app</live-example>.
+
+  For the tests features in the testing guides, see <live-example name="testing" stackblitz="specs" noDownload>tests</live-example>.
+
+</div>
+
+
+Debug specs in the browser in the same way that you debug an application.
+
+1. Reveal the Karma browser window. See [Set up testing](guide/testing#set-up-testing) if you need help with this step.
+1. Click the **DEBUG** button; it opens a new browser tab and re-runs the tests.
+1. Open the browser's “Developer Tools” (`Ctrl-Shift-I` on Windows; `Command-Option-I` in macOS).
+1. Pick the "sources" section.
+1. Open the `1st.spec.ts` test file (Control/Command-P, then start typing the name of the file).
+1. Set a breakpoint in the test.
+1. Refresh the browser, and it stops at the breakpoint.
+
+<div class="lightbox">
+  <img src='generated/images/guide/testing/karma-1st-spec-debug.png' alt="Karma debugging">
+</div>
+
+<hr>
+