Flags and Tags

All test rules have some common attributes. Useful examples are size and timeout .

Size is an architectural hint. It implies a timeout, and the scheduler also reserves more RAM.

• small = unit test, short timeout
• medium = functional test, moderate timeout
• large = integration test, long timeout
• enormous = end-to-end test, eternal timeout

You could specify an explicit timeout in addition to (or instead of) size .

Size is useful for filtering. For example, you can use --test_size_filters=small to ask Bazel to "just run the unit tests".

You can also filter with these flags:

• --test_tag_filters, for example, with =smoke to run tests with a custom tag "smoke"
• --test_timeout_filters, for example, with =-eternal to skip running tests that take a long time. Note that by default eternal is 15 minutes. See https://bazel.build/reference/test-encyclopedia#role-test-runner.
• --test_lang_filters, for example with =js,go to run just the js_test and go_test targets

Well-known tags

You can add these to the tags attribute of a test to change the way Bazel runs it.

• external - the test is intentionally non-hermetic, as it tests something aside from its declared inputs. Forces the test to be unconditionally executed, regardless of the value of --cache_test_results, so the result is not cached.
• exclusive - the test is not isolated and can interact with other tests running at the same time. Exclusive tests are executed in serial fashion after all build activity and non-exclusive tests have been completed. They can't be run remotely, either.
• manual - essentially "skip" or "disabled". It means a target wildcard pattern, like :all or //... won't include this target. You can still run it by listing the target explicitly.
• requires-network - declare that the test should run in a sandbox that allows network access.
• flaky - run it up to three times when it fails. We’ll learn more about flakiness in a later lesson.

The Aspect CLI provides a handy way to find these: bazel help tags

Next Lesson