rspec you can typically call the
stub method to stub something out. However, this method only works inside an
example or a
before(:each) block. Try using rspec stubs anywhere else and you get the following error message
The use of doubles or partial doubles from rspec-mocks outside of the per-test lifecycle is not supported.
What if you wanted to temporarily stub out one object inside a
before(:all) (since you like those fast test, don't you ;) or globally for the entire test suite for say disabling image processing. How would you do that?
Simple, Ruby has this magic word called
metaprogramming to rescue us.
Instead of doing:
image = Image.new image.stub(:process).and_return(true)
image = Image.new def image.process true end
That is it. We just overwrote the definition of the process method for only this one image instance. No side-effect or stub-code leakage will occur here.