Make the test bite

A test that cannot fail proves nothing. Before I trust a regression test, I put the bug back, run the suite, and watch the test fail. Then I restore the fix and watch it pass.

A green suite only tells me the code and the test agree right now. Making the test bite tells me they hold together under attack: remove the fix, and the assertion falls.

The tombstone fix in context-bridge is the one I keep coming back to. It turned a single marker into a cumulative set, and the test was the exact failure: unlink A, link B, unlink B, and both must stay rejected. I reverted the fix, and the test dropped — A was forgotten, precisely as the bug described.

If step two does not fail, stop. Usually it means the test was written against my idea of the fix rather than the behaviour that broke. That is a different bug, and the bite catches it too.