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Tests ruby code as it changes, in parallel
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test-loop - Continuous testing for Ruby with fork/eval

test-loop is a fast continuous testing tool for Ruby that continuously detects and tests changes in your Ruby application in an efficient manner, whereby it:

  1. Absorbs the test execution overhead into the main Ruby process.
  2. Forks to evaluate your test files directly and without overhead.

It relies on file modification times to determine what parts of your Ruby application have changed and then uses Rake's String#pathmap function to determine which test files in your test suite correspond to those changes.


  • Tests CHANGES in your Ruby application; does NOT run all tests every time.

  • Reabsorbs test execution overhead if the test or spec helper file changes.

  • Mostly I/O bound, so you can have it always running without CPU slowdowns.

  • Supports Test::Unit, RSpec, or any other testing framework that is utilized by your application's test/test_helper.rb and spec/spec_helper.rb files.

  • Implemented in less than 40 (SLOC) lines of code! :-)


As a Ruby gem:

gem install test-loop

As a Git clone:

git clone git://


If installed as a Ruby gem:


If installed as a Git clone:

ruby bin/test-loop


  • Press Control-Z (or send the SIGTSTP signal) to forcibly run all tests, even if there are no changes in your Ruby application.

  • Press Control-\ (or send the SIGQUIT signal) to forcibly reabsorb the test execution overhead, even if its sources have not changed.

  • Press Control-C (or send the SIGINT signal) to quit the test loop.


See the LICENSE file for details.

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