FakeFS ====== Mocha is great. But when your library is all about manipulating the filesystem, you really want to test the behavior and not the implementation. If you're mocking and stubbing every call to FileUtils or File, you're tightly coupling your tests with the implementation. def test_creates_directory FileUtils.expects(:mkdir).with("directory").once Library.add "directory" end The above test will break if we decide to use `mkdir_p` in our code. Refactoring code shouldn't necessitate refactoring tests. With FakeFS: def test_creates_directory Library.add "directory" assert File.directory?("directory") end Woot. Usage ----- require 'fakefs' # That's it. Don't Fake the FS Immediately ----------------------------- require 'fakefs/safe' FakeFS.activate! # your code FakeFS.deactivate! # or FakeFS do # your code end How is this different than MockFS? ---------------------------------- FakeFS provides a test suite and works with symlinks. It's also strictly a test-time dependency: your actual library does not need to use or know about FakeFS. Speed? ------ http://gist.github.com/150348 Authors ------- * Chris Wanstrath [chris@ozmm.org] * Pat Nakajima [http://github.com/nakajima]