CODEWITHSUNDEEP
ruby-on-railsrubyrspec
jtmarmon
jtmarmon

Reputation: 6209

Rspec - expect to receive only if method exists

In rspec, you can use an instance_double to ensure that your expectations are valid - in other words, if I have:

class Foo
  def bar
  end
end

I can do

dbl = instance_double('Foo')
expect(dbl).to receive(:bar)
...

and I know that if I remove the bar method from Foo, my test will throw an error, preventing me from silently breaking things.

How can I achieve this same effect with class methods? I just accidentally caused a bug which my tests didn't catch, because I did the following:

class Foo
  def self.bar
  end
end

Test:

expect(Foo).to receive(:baz)
Foo.baz

No errors were raised because I added a stub via the above expectation, but really that method doesn't exist. I'm aware I could do class_double, but Foo.baz is called in another part of my code, not in my test, so I can't get it to call the class_double instead of the actual class.

Upvotes: 1

Views: 1062

Answers (1)

Frederick Cheung
Frederick Cheung

Reputation: 84182

What you want to do is turn on partial double verification: 

RSpec.configure do |config|
  config.mock_with :rspec do |mocks|
    mocks.verify_partial_doubles = true
  end
end

This will cause partial doubles to have the same behaviour as doubles created via object_double.

Upvotes: 1

Related Questions