Guardfile.rb

guard 'minitest' do
  # Run all tests if the test_helper.rb file is changed
  watch('test/test_helper.rb') { 'test' }

  # Run all tests if we change a .rb file in lib or config
  #watch(%r{^(lib|config)/(.*)\.rb}) { 'test' }

  # If a model is changed, run the corresponding unit test file
  watch(%r{^app/models/(.*)\.rb$}) { |m| "test/unit/#{m[1]}_test.rb" }

  # If an asset model is changed, run all asset inherited unit tests
  watch(%r{^app/models/(asset|image|document)\.rb$}) { |m| [ "test/unit/asset_test.rb", "test/unit/document_test.rb", "test/unit/image_test.rb" ] }

  # If a controller is changed, run the corresponding functional test file
  watch(%r{^app/controllers/(.*)\.rb$}) { |m| "test/functional/#{m[1]}_test.rb" }

  # If a helper file is changed, and a unit test exists for it, run that test
  watch(%r{^app/helpers/(.*)_helper\.rb$}) { |m| [ "test/unit/helpers/#{m[1]}_helper_test.rb", "test/functional/#{m[1]}_controller_test.rb" ] }

  # If a mailer is changed, run the corresponding unit test file
  watch(%r{^app/mailers/(.*)\.rb$}) { |m| "test/functional/#{m[1]}_test.rb" }

  # Watch all test files and re-run them if they change.
  watch(%r{^test/(.*)_test\.rb$})

  # Watch fixtures and factories and re-run all tests if they change
  watch(%r{^test/(factories|fixtures|uploads)/(.*)}) { 'test' }
end