Practice workspaceY
Learning path
LEVEL 7 · TESTING & REFACTORING

A green test can be a false signal

Detect tests that no longer check the intended behavior.

01 / PREDICT

What happens when the only assertion is deleted?

02 / EXPLAIN

The judgment behind the action

Some test runners allow a test body to complete without a useful assertion. Review what the test establishes, not just its exit status. Check that a regression test fails before the fix and succeeds after it. Fixture results in cglearn are simulated evidence.

03 / DEMONSTRATE

A bounded way to ask

Inspect the assertion diff. Restore an assertion that checks the expected task IDs, then request before-and-after verification.
04 / PRACTICE

Identify a removed assertion hidden inside a green test report.

What happens when the only assertion is deleted?

Choose the best next action

Guided practice contributes completion, not independent mastery.

06 / REFLECT

Make the lesson yours.

Your reflection is attached when you submit your decision. Drafts remain in this tab.

07 / TRANSFER

Try it somewhere unfamiliar.

Apply this skill to an unfamiliar repository: identify a removed assertion hidden inside a green test report. Record the evidence you would need.

Choose your next practice
Source checked 2026-09-09 · Documentation profile · Runtime example untestedOfficial reference