I tried to replace
self.fixture_class_names = self.fixture_class_names.merge(class_names)
self.fixture_class_names.merge!(class_names) # Why does this fail?
in rails source, and it failed 2 tests.
What is the difference between the two?
Could it have something to do with the fact that the fixture_class_names
hash has a block to generate values that were not assigned?
Or is this because fixture_class_names is a class attribute?