test-with watches your current directory and runs the command you specify every time something is changed. I find it valuable because...

test-with truffle test will display real-time results of your Ethereum app test suite

test-with rails test will display real-time results of your Rails app test suite

test-with rails test test/controllers will display real-time results of your controllers tests

test-with ruby letter_test.rb will display real-time results of the Ruby test file

test-with python tests.py will display real-time results of the Python test file

test-with git status will display real-time list of changes in the directory

Run in your terminal

gem install test_with

See above, the very top.

The gem is available as open source under the terms of the MIT License.