qrush/m

A Test::Unit runner that can run tests by line number.

Ruby

391

198 commits

updated Dec 20, 2025

See the code

README

M.RB

m stands for metal, a better test/unit and minitest test runner that can run tests by line number.

INSTALL

Install via:

$ gem install m

If you’re using Bundler, you’ll need to include it in your Gemfile. Toss it into the test group:

group :test do
  gem "m"
end

USAGE

Basically, I was sick of using the -n flag to grab one test to run. Instead, I prefer how RSpec’s test runner allows tests to be run by line number.

Given this file:

$ cat -n test/example_test.rb
 1  require 'test/unit'
 2
 3  class ExampleTest < Test::Unit::TestCase
 4    def test_apple
 5      assert_equal 1, 1
 6    end
 7
 8    def test_banana
 9      assert_equal 1, 1
10    end
11  end

You can run a test by line number, using format m TEST_FILE:LINE_NUMBER_OF_TEST:

$ m test/example_test.rb:4
Run options: -n /test_apple/

# Running tests:

.

Finished tests in 0.000525s, 1904.7619 tests/s, 1904.7619 assertions/s.

1 tests, 1 assertions, 0 failures, 0 errors, 0 skips

Hit the wrong line number? No problem, m helps you out:

$ m test/example_test.rb:2
No tests found on line 2. Valid tests to run:

 test_apple: m test/examples/test_unit_example_test.rb:4
test_banana: m test/examples/test_unit_example_test.rb:8

Want to run the whole test? Just leave off the line number.

$ m test/example_test.rb
Run options:

# Running tests:

..

Finished tests in 0.001293s, 1546.7904 tests/s, 3093.5808 assertions/s.

1 tests, 2 assertions, 0 failures, 0 errors, 0 skips

If you want to run all the tests in a directory as well as its subdirectories, use the -r flag:

$ m -r test/models
"Searching provided directory for tests recursively"
Run options:

..

Finished in 3.459902s, 45.0880 runs/s, 87.5747 assertions/s.

156 tests, 303 assertions, 0 failures, 0 errors, 13 skips

If you need to pass some option down to the actual runner, that is also supported:

$ m test/models -- --seed 1234
Run options: --seed 1234

..

Finished in 3.459902s, 45.0880 runs/s, 87.5747 assertions/s.

156 tests, 303 assertions, 0 failures, 0 errors, 13 skips

Ensure that you use the -- before the options, otherwise you'll get an invalid option error. Also, these extra option should always be the last argument.

SUPPORT

m works with a few Ruby test frameworks:

  • Minitest::Test
  • Minitest::Spec
  • Test::Unit
  • ActiveSupport::TestCase

CONTRIBUTING

Testing

You can run all the tests with:

bundle exec rake test

LICENSE

This gem is MIT licensed, please see LICENSE for more information.

Contributors

qrush

66 commits

zamith

40 commits

jeremyevans

21 commits

blowmage

18 commits

qrush/m

A Test::Unit runner that can run tests by line number.

Ruby

391

198 commits

updated Dec 20, 2025

See the code

README

M.RB

m stands for metal, a better test/unit and minitest test runner that can run tests by line number.

INSTALL

Install via:

$ gem install m

If you’re using Bundler, you’ll need to include it in your Gemfile. Toss it into the test group:

group :test do
  gem "m"
end

USAGE

Basically, I was sick of using the -n flag to grab one test to run. Instead, I prefer how RSpec’s test runner allows tests to be run by line number.

Given this file:

$ cat -n test/example_test.rb
 1  require 'test/unit'
 2
 3  class ExampleTest < Test::Unit::TestCase
 4    def test_apple
 5      assert_equal 1, 1
 6    end
 7
 8    def test_banana
 9      assert_equal 1, 1
10    end
11  end

You can run a test by line number, using format m TEST_FILE:LINE_NUMBER_OF_TEST:

$ m test/example_test.rb:4
Run options: -n /test_apple/

# Running tests:

.

Finished tests in 0.000525s, 1904.7619 tests/s, 1904.7619 assertions/s.

1 tests, 1 assertions, 0 failures, 0 errors, 0 skips

Hit the wrong line number? No problem, m helps you out:

$ m test/example_test.rb:2
No tests found on line 2. Valid tests to run:

 test_apple: m test/examples/test_unit_example_test.rb:4
test_banana: m test/examples/test_unit_example_test.rb:8

Want to run the whole test? Just leave off the line number.

$ m test/example_test.rb
Run options:

# Running tests:

..

Finished tests in 0.001293s, 1546.7904 tests/s, 3093.5808 assertions/s.

1 tests, 2 assertions, 0 failures, 0 errors, 0 skips

If you want to run all the tests in a directory as well as its subdirectories, use the -r flag:

$ m -r test/models
"Searching provided directory for tests recursively"
Run options:

..

Finished in 3.459902s, 45.0880 runs/s, 87.5747 assertions/s.

156 tests, 303 assertions, 0 failures, 0 errors, 13 skips

If you need to pass some option down to the actual runner, that is also supported:

$ m test/models -- --seed 1234
Run options: --seed 1234

..

Finished in 3.459902s, 45.0880 runs/s, 87.5747 assertions/s.

156 tests, 303 assertions, 0 failures, 0 errors, 13 skips

Ensure that you use the -- before the options, otherwise you'll get an invalid option error. Also, these extra option should always be the last argument.

SUPPORT

m works with a few Ruby test frameworks:

  • Minitest::Test
  • Minitest::Spec
  • Test::Unit
  • ActiveSupport::TestCase

CONTRIBUTING

Testing

You can run all the tests with:

bundle exec rake test

LICENSE

This gem is MIT licensed, please see LICENSE for more information.

Contributors

qrush

66 commits

zamith

40 commits

jeremyevans

21 commits

blowmage

18 commits

Languages

Ruby

100.0%