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tdd

tdd

github.com/backnotpropTesting & quality3.1k5.6k installsUpdated today
Repository

About tdd

A bug-fixing skill for developers using test-driven development when a clear, practical test path exists. It prioritizes a focused regression check that demonstrates the failure before the fix and verifies the result afterward, while allowing other checks when tests are impractical.

Key features

  1. 01Identify intended and current behavior
  2. 02Choose the narrowest practical check
  3. 03Write and run a failing test first
  4. 04Verify the fix with regression checks
  5. 05Use alternatives when tests are impractical

Use cases

  1. 01Fixing a bug with a reproducible test path
  2. 02Verifying a fix when a new test is impractical

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/backnotprop/pstack --skill tdd

After installing, type/tddin Claude Code to confirm it loaded.

Details

From the project README

TDD Bug Fix

When fixing a bug with a clear, cheap test path, make the broken behavior executable before changing production code. The goal is a focused regression test that fails before the fix and passes after it.

Do not force a test when it would be impractical. If the available test would require broad harness setup, brittle mocks, slow end-to-end infrastructure, production-only state, vague reproduction steps, or large unrelated fixture churn, skip adding a new test and use the closest useful verification instead.

Workflow

  1. Understand the bug. Identify the intended behavior, current behavior, affected path, and smallest observable reproduction.
  2. Choose the narrowest executable check. Prefer the closest unit, component, integration, or regression test already used for that codepath. If no practical test path is obvious, do not create one from scratch just to satisfy the workflow.
  3. Write the failing test first. Add the smallest focused test that would have caught the bug. The test should encode intended behavior, not mirror the current implementation.
  4. Run the new test before fixing. Confirm it fails for the intended reason. If it passes or fails for an unrelated reason, correct the test or reproduction before editing the implementation.
  5. Fix the bug. Make the smallest production change that satisfies the intended behavior while preserving nearby contracts.
  6. Rerun the regression test. Confirm the test now passes.

If a Failing Test Is Impractical

Use the closest executable regression check instead: a targeted script, manual reproduction command, browser automation, snapshot comparison, log assertion, or focused integration check.

Prefer no new test over a bad test. A bad test is one that mostly tests mocks, encodes current implementation details, depends on timing or unrelated global state, needs expensive infrastructure for a small fix, or would be deleted immediately after proving the fix.

Guardrails

  • Do not change tests merely to match a wrong implementation.
  • Do not weaken existing assertions unless the expected behavior has genuinely changed and the reason is clear.
  • Keep the regression test focused on the bug. Avoid broad fixture churn or unrelated coverage expansion.
  • If the bug is flaky, make the test deterministic where possible and document the signal being locked down.
  • If the bug exposes a broader class of failures, first land the focused regression path, then consider additional sibling coverage.

Final Response

Report the evidence, not just the outcome:

  • Name the failing-before test or executable check and the failure it produced.
  • Name the passing-after test run and any nearby validation performed.
  • If failing-before evidence could not be demonstrated, state why and describe the closest regression check used instead.

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