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 you may include FakeFS::SpecHelpers to turn FakeFS on and off in a given example group:
require 'fakefs/spec_helpers'
describe "my spec" do
include FakeFS::SpecHelpers
end
See lib/fakefs/spec_helpers.rb for more info.
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.
FakeFS internally uses the Pathname and FileUtils constants. If you use
these in your app, be certain you're properly requiring them and not counting
on FakeFS' own require.
$ gem install fakefs
$ rip install git://github.com/defunkt/fakefs.git
Once you've made your great commits:
- Fork FakeFS
- Create a topic branch -
git checkout -b my_branch - Push to your branch -
git push origin my_branch - Create an Issue with a link to your branch
- That's it!
- 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