Run only the tests that changed (RSpec or Minitest). Fast.

quick_check installs a qc command that finds changed/added test files (staged, unstaged, and untracked by default) and runs them using the appropriate test runner automatically.

Install the gem and run qc to run the tests that changed.

gem install quick_check
qc

• Detects changed test files under:
  • RSpec: spec/**/*_spec.rb
  • Minitest: test/**/*_test.rb
  • Also maps changed source files to their tests:
    • app/models/user.rb -> spec/models/user_spec.rb / test/models/user_test.rb
    • app/controllers/home_controller.rb -> spec/requests/home_spec.rb or spec/requests/home_controller_spec.rb (fallbacks), and controller tests as fallback; similarly for Minitest under test/integration and test/controllers
    • lib/foo/bar.rb -> spec/lib/foo/bar_spec.rb / test/lib/foo/bar_test.rb
• Includes (by default):
  • Unstaged working tree changes
  • Staged (index) changes
  • Untracked files (new specs not yet added)
  • All committed changes on your branch vs base (main/master)
  • Renames and copies are tracked so moved tests still run
• You can disable branch commits with --no-committed
• Auto-detects base branch (main or master) or configure via .quick_check.yml
• Auto-detects framework and command:
  • RSpec: bundle exec rspec <files>
  • Rails + Minitest: bin/rails test <files> (or bundle exec rails test <files>)
  • Plain Minitest: per-file ruby -I test <file>
• Always prints the full command(s) before executing
• --cmd to override the command for advanced use-cases

From source:

gem install quick_check

Once installed, the qc executable will be available in your shell.

# Run all changed tests in your branch (default: committed + staged + unstaged + untracked)
qc

# Print matching spec file paths only (no execution)
qc --print

# Dry-run: print the exact command that would run
qc --dry-run

# Only current edits (ignore previously committed changes in this branch)
qc --no-committed

# Specify/override the base branch
qc --base main

# Only committed changes vs base (ignore working tree)
qc --no-staged --no-unstaged

# Use a custom test command
qc --cmd "bundle exec rspec --fail-fast"

# Verbose output
qc --verbose

• --base BRANCH: Base branch to diff against (overrides config)
• --committed / --no-committed: Include or exclude committed changes vs base (default: include)
• --no-staged: Ignore staged changes
• --no-unstaged: Ignore unstaged changes
• --cmd CMD: Override test command (default: auto-detected runner)
• -p, --print: Only print matched files, do not run
• -n, --dry-run: Print the command that would run and exit
• -v, --verbose: Verbose/debug output
• -h, --help: Show help

Create .quick_check.yml in the repo root (or current directory) to set defaults:

# .quick_check.yml
base_branch: main

If no config is present, qc will use the first existing branch among main or master.

• Unstaged: git diff --name-only -M -C --diff-filter=ACMR
• Staged: git diff --name-only --cached -M -C --diff-filter=ACMR
• Untracked: git ls-files --others --exclude-standard
• Committed vs base: git diff --name-only -M -C --diff-filter=ACMR <base>...HEAD

Files are filtered to spec/**/*_spec.rb and/or test/**/*_test.rb, de-duplicated, sorted, and then:

• For RSpec: run once via bundle exec rspec <files>
• For Rails + Minitest: run once via rails test <files>
• For plain Minitest: run each file via ruby -I test <file>

The CLI prints each full command before executing. With --dry-run, it only prints and exits.

Notes:

• We intentionally exclude deletions (D) so removed tests are not attempted to run.
• Renames (R) and copies (C) are included, so moved tests are still executed.

• Returns non-zero if any executed command fails
• Returns 0 if no changed/added spec files are detected

MIT