test-focus

created	"2026-01-19T00:00:00.000Z"
modified	"2026-05-09T00:00:00.000Z"
reviewed	"2026-04-25T00:00:00.000Z"
allowed-tools	Bash, Read, Grep, Glob, TodoWrite
args	<file-path> [--serial] [--debug]
argument-hint	<file-path> [--serial] [--debug]
description	Run one test file fail-fast for rapid TDD — Playwright, Vitest, Jest, pytest, cargo, go test. Use when iterating on a failing spec, headed/debug mode, or serial WebGL tests.
name	test-focus

When to Use This Skill

Use this skill when...	Use test-run instead when...
Iterating on a single failing spec with fail-fast feedback	Running the full test suite for a project
Forcing serial execution for WebGL or shared-state tests	Running tests in watch mode across many files (use test-quick)
Running one test file in headed/debug mode	Triaging a directory of test results (use test-analyze)
Sub-30s feedback on a known-broken file	Choosing which tier to run (use test-tier-selection)

Context

• Project files: !find . -maxdepth 1 \( -name 'pyproject.toml' -o -name 'package.json' -o -name 'Cargo.toml' -o -name 'go.mod' \)
• Playwright config: !find . -maxdepth 1 -name 'playwright.config.*'
• Vitest config: !find . -maxdepth 1 \( -name 'vitest.config.*' -o -name 'vite.config.*' \)
• Jest config: !find . -maxdepth 1 -name 'jest.config.*'
• Pytest config: !find . -maxdepth 1 \( -name pyproject.toml -o -name setup.cfg \) -exec grep -l 'pytest' {} +
• Package.json exists: !find . -maxdepth 1 -name 'package.json' -type f

Parameters

• $1 (required): Test file path or pattern (e.g., login.spec.ts, tests/e2e/auth.spec.ts)
• --serial: Force sequential execution with single worker (useful for WebGL, database tests)
• --debug: Run in debug/headed mode for visual debugging

Your task

Run a single test file in fail-fast mode for rapid development iteration. Stop immediately on first failure to minimize feedback time.

1. Detect test framework and construct command

Playwright (if playwright.config.* exists):

# Standard fail-fast
bunx playwright test "$FILE" --max-failures=1 --reporter=line

# With --serial (WebGL, shared state)
bunx playwright test "$FILE" --max-failures=1 --workers=1 --reporter=line

# With --debug
bunx playwright test "$FILE" --max-failures=1 --headed --debug

Vitest (if vitest.config.* or vite.config.* exists):

# Standard fail-fast
bunx vitest run "$FILE" --bail=1 --reporter=dot

# With --serial
bunx vitest run "$FILE" --bail=1 --pool=forks --poolOptions.threads.singleThread --reporter=dot

# With --debug
bunx vitest run "$FILE" --bail=1 --inspect-brk

Jest (if jest.config.* exists):

# Standard fail-fast
bunx jest "$FILE" --bail --silent

# With --serial
bunx jest "$FILE" --bail --runInBand --silent

# With --debug
bunx jest "$FILE" --bail --runInBand

pytest (Python projects):

# Standard fail-fast
python -m pytest "$FILE" -x -v --tb=short

# With --serial (already serial by default)
python -m pytest "$FILE" -x -v --tb=short

# With --debug
python -m pytest "$FILE" -x -v --tb=long -s

Cargo test (Rust projects):

# Standard fail-fast
cargo test --test "$FILE" -- --test-threads=1

# With --debug
cargo test --test "$FILE" -- --test-threads=1 --nocapture

Go test:

# Standard fail-fast
go test -v -failfast "$FILE"

# With --debug
go test -v -failfast "$FILE" -count=1

2. Execute the test

Run the constructed command. Capture and display output.

3. Analyze results

If the test passes:

[FILE]: PASSED
Duration: Xs

Ready for next iteration or file.

If the test fails:

[FILE]: FAILED (stopped at first failure)
Duration: Xs

First failure:
  Test: [test name]
  Error: [brief error message]
  Location: [file:line]

Quick actions:
- Fix the issue and re-run: /test:focus [same file]
- Debug visually: /test:focus [file] --debug
- See full output: /test:run [file]

4. Provide rerun command

Always show the exact command to rerun:

Rerun: /test:focus $FILE

Time savings context

Focused testing dramatically reduces feedback time:

Approach	Typical Duration	Use Case
/test:focus	2-30 seconds	Iterating on single file
/test:quick	30 seconds	Unit tests after changes
/test:full	5-30 minutes	Before commit/PR

Agentic optimizations

Context	Flags
Playwright fast	--max-failures=1 --reporter=line
Playwright WebGL	--max-failures=1 --workers=1 --reporter=line
Vitest fast	--bail=1 --reporter=dot
Jest fast	--bail --silent
pytest fast	-x -v --tb=short

Error handling

• If file not found: List similar test files with glob and suggest corrections
• If framework not detected: Show available package.json scripts containing "test"
• If test times out: Suggest --serial flag or increasing timeout