# flaky-test-triage

A slash command that hunts down tests failing intermittently without code changes, names the source — race, order coupling, leaked state — and fixes it.

- command · `type=command` · Claude Code · 24 installs
- Author: davila7
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/davila7/claude-code-templates/tree/HEAD/cli-tool/components/commands/testing/flaky-test-triage.md
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/commands/flaky-test-triage

## What it does

Give it a test file or a single case name. The command runs that target 20 times and keeps going after a failure, so you get a real pass/fail ratio instead of one unlucky run. It picks the runner from project config and has loops ready for Vitest, Jest, Pytest, Go and Cargo.

Failures get sorted into four buckets: async races, order dependency and shared state, clock or timezone skew, and port or file contention. Then come the edits. The command holds `Read`, `Glob`, `Grep`, `Edit`, `Write` and `Bash`, so it changes the test rather than describing a fix: fixed `sleep()` calls turn into polling with a timeout, `afterEach` restores mocks, temp dirs get unique names.

A clean working tree is a hard prerequisite. Any pending change trips the `git status --porcelain` check and the run stops with a request to commit or stash. For Pytest, shuffled ordering is used only when a plugin is actually there; the flags for `pytest-random-order` and `pytest-randomly` are probed first. Five tens of consecutive runs follow, plus the project's whole suite, to show the flake is gone and nothing else broke.

## Install

### Claude Code (native platform)

1. **claude-code-templates**
```bash
npx claude-code-templates@latest --command testing/flaky-test-triage
```

2. **Manually: put the files in place**
- File: `.claude/commands/flaky-test-triage.md` — Call it with /flaky-test-triage. For all projects use ~/.claude/commands/

### Codex

**Manually: put the files in place**
- File: `~/.codex/prompts/flaky-test-triage.md` — Call it with /prompts:flaky-test-triage. Codex marks this format deprecated in favour of skills

### GitHub Copilot

**Manually: put the files in place**
- File: `.github/prompts/flaky-test-triage.prompt.md`

### Gemini CLI

**Manually: put the files in place**
- File: `.gemini/commands/flaky-test-triage.toml` — Gemini stores commands as TOML: the prompt text goes into the prompt field

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/davila7/claude-code-templates/tree/HEAD/cli-tool/components/commands/testing/flaky-test-triage.md

## When to use it
- measure how often a test really fails
- tell a race apart from state leaking between tests
- replace arbitrary sleeps with condition polling
- give each run its own port and temp folder
- prove a fix with repeated runs

## Example prompts
- Triage the intermittent failure in `src/api/order.test.ts`
- Run `checkout.spec.ts` twenty times and find out why it fails
- Deflake the `TestPaymentRetry` test

## Source text · flaky-test-triage.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 8f0f444bcca8f8eb.

BEGIN THIRD-PARTY FILE 8f0f444bcca8f8eb
````text
---
allowed-tools: Read, Glob, Grep, Edit, Write, Bash
argument-hint: <test-file-or-test-name>
description: Detect, isolate, and remediate non-deterministic or flaky tests through stress-repetition and root-cause analysis
---

# Flaky Test Triage

Investigate and eliminate non-deterministic behavior for: **$ARGUMENTS**

## Purpose

Isolate tests that pass and fail intermittently without code changes, determine the underlying source of non-determinism (race conditions, order coupling, timing drift, or leaked state), and apply robust deflaking fixes.

## Pre-flight

1. Confirm working tree cleanliness before running repeated test runs:
   ```bash
   test -z "$(git status --porcelain)" || { echo "Working tree is dirty; commit or stash changes first."; exit 1; }
   ```
2. Identify the target test file or test case from `$ARGUMENTS`.
3. Detect the test framework in use (e.g., Jest, Vitest, Pytest, Go test, Cargo test) from project configuration.

## Triage & Stabilization Workflow

### 1. Stress Repetition to Measure Flake Frequency

Run the target test for 20 iterations without breaking early on first error so the full pass/fail ratio and flake frequency can be accurately quantified:

- **Vitest**:
  ```bash
  passes=0; fails=0
  for i in $(seq 1 20); do
    if npx vitest run <path-to-test>; then ((++passes)); else ((++fails)); fi
  done
  echo "Vitest Results: $passes passed, $fails failed out of 20 runs"
  ```
- **Jest**:
  ```bash
  passes=0; fails=0
  for i in $(seq 1 20); do
    if npx jest <path-to-test> --runInBand; then ((++passes)); else ((++fails)); fi
  done
  echo "Jest Results: $passes passed, $fails failed out of 20 runs"
  ```
- **Pytest**:
  ```bash
  passes=0; fails=0
  for i in $(seq 1 20); do
    if pytest <path-to-test> -v; then ((++passes)); else ((++fails)); fi
  done
  echo "Pytest Results: $passes passed, $fails failed out of 20 runs"
  ```
- **Go**:
  ```bash
  go test -count=20 -run <TestName> <package-path>
  ```
- **Cargo**:
  ```bash
  passes=0; fails=0
  for i in $(seq 1 20); do
    if cargo test <test_name> -- --nocapture; then ((++passes)); else ((++fails)); fi
  done
  echo "Cargo Results: $passes passed, $fails failed out of 20 runs"
  ```

Record the pass/fail ratio and capture stdout/stderr from failed iterations.

### 2. Diagnose Flake Root Cause

Categorize the failure using the common non-determinism taxonomy:

1. **Timing & Asynchronous Race Conditions**:
   - Symptom: Fails under high CPU load or CI runners; passes on fast local hardware.
   - Indicators: Arbitrary `sleep()`, `setTimeout()`, or unawaited promises/goroutines.
   - Root cause: Test asserts before an asynchronous background operation resolves.

2. **Test Order Dependency & State Pollution**:
   - **Symptom**: Passes when executed in isolation (`--testNamePattern`), fails when the entire suite runs.
   - **Indicators**: Leaked global variables, uncleared database records, singleton caches, or shared filesystem artifacts.
   - **Verification**: Use the framework's shuffle support when it is installed. For Pytest, detect optional plugins before passing their flags:
     ```bash
     if pytest --help 2>/dev/null | grep -q -- '--random-order'; then
       pytest <path-to-test> --random-order
     elif pytest --help 2>/dev/null | grep -q -- '--randomly-seed'; then
       pytest <path-to-test> --randomly-seed=random
     else
       echo 'No Pytest randomization plugin detected; record order-randomization as unavailable.'
       pytest <path-to-test> -v
     fi
     ```
````
END THIRD-PARTY FILE 8f0f444bcca8f8eb

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