Reviewing Test Changes

In one sentence

Reviewing test changes means checking whether tests still constrain behavior—or whether they were edited to make a weak implementation look green.

Why it matters

Agents and humans both “fix” failing suites by relaxing assertions. Green CI then certifies less than reviewers assume.

How it works

• Diff tests with the same seriousness as product code.
• Watch for deleted edge cases, broadened matchers, skipped tests, and snapshots regenerated without rationale.
• Ask whether new tests would fail if the bug were reintroduced.
• Prefer behavior assertions over implementation-detail locks unless the detail is the contract.

Example

A PR changes `expect(status).toBe(403)` to `expect(status).toBeGreaterThanOrEqual(400)` while “fixing” auth. That is a weaker guarantee. Call it out before approval.