I want to use GoMock to test some code, without coupling my tests too tightly to the actual implementation of the thing under test. But GoMock seems to require that I be able to say in advance exactly what calls the code under test will make, even if that's not part of the contract I'm trying to test. Is there a way around this?
For example, say I'm testing some validation logic, where the code under test is required to take a Widget named mockedObject, and return false if either mockedObject.CheckConditionA() or mockedObject.CheckCondition1() returns false, and to return true otherwise. One correct implementation is:
func UnderTest(mockedObject *Widget) bool {
if !mockedObject.CheckConditionA() {
return false
}
return mockedObject.CheckCondition1()
}
Another is:
func UnderTest(mockedObject *Widget) bool {
if !mockedObject.CheckCondition1() {
return false
}
return mockedObject.CheckConditionA()
}
A third is:
func UnderTest(mockedObject *Widget) bool {
cA := mockedObject.CheckConditionA()
c1 := mockedObject.CheckCondition1()
return cA && c1
}
And a fourth is:
func UnderTest(mockedObject *Widget) bool {
if TodayIsAnAlternateTuesday() {
return mockedObject.CheckCondition1() && mockedObject.CheckConditionA()
}
return mockedObject.CheckConditionA() && mockedObject.CheckCondition1()
}
My test shouldn't have to care which of these is being used; I just want to check that the contract is fulfilled.
How do I set up the mocks for a test like this, where the code under test is allowed but not required to call a method?
For the test for the case where CheckConditionA() will return false, I need to set up something like mockedObject.EXPECT().CheckConditionA().Return(false). But some of these implementations will also require a mockedObject.EXPECT().CheckCondition1().Return(true) in order to work, or my test will fail due to unexpected calls. On the other hand, some will fail if I provide that EXPECT, due to missing calls.
Does GoMock just not support writing this kind of test? If not, what else could I be using that would let me test this function without constructing a real live Widget?
