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.
require 'fakefs'
# That's it.
require 'fakefs/safe'
FakeFS.activate!
# your code
FakeFS.deactivate!
# or
FakeFS do
# your code
end
The above approach works with RSpec as well. In addition to this you may use the 'use_fakefs' macro to turn FakeFS on and off in a given example group. See lib/spec_helpers for more details on it's usage.
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.
$ gem install fakefs
$ rip install git://github.com/defunkt/fakefs.git
- Code:
git clone git://github.com/defunkt/fakefs.git
- Home: http://github.com/defunkt/fakefs
- Docs: http://defunkt.github.com/fakefs
- Bugs: http://github.com/defunkt/fakefs/issues
- List: http://groups.google.com/group/fakefs
- Test: http://runcoderun.com/defunkt/fakefs
- Gems: http://gemcutter.org/gems/fakefs
- Boss: Chris Wanstrath :: http://github.com/defunkt