Audit a test suite for value versus noise

A suite that takes 20 minutes and nobody trusts the red runs.

Audit the test suite below. I want to know which tests are worth their maintenance cost.

Classify each test as:
- **Keep**: would catch a real bug, is clear when it fails.
- **Fix**: tests the right thing badly, whether unclear, slow, or over-mocked.
- **Merge**: duplicates another test's coverage.
- **Delete**: asserts implementation detail, tests the framework or the language, or has never failed for a real reason.

For each, one line of justification. Then:
1. Estimate what proportion of the suite is doing real work.
2. Name the slowest tests and whether their coverage justifies the time.
3. Identify coverage that would be lost by the deletions, and say whether it matters.

Be willing to recommend deleting a lot. Do not hedge by keeping everything.

Test suite:

Test strategy. Unit or integration, what to skip, fixture design, and pruning a suite that costs too much.