Verify after ThenReturn does not seem to work with Never()

[jacksehr]

Just double checking if this is a bug or simply not how the API is meant to be used -- the docs explain that the following is available to verify a stub was used correctly:

When(greeter.Greet("John")).ThenReturn("hello world").Verify(Once())

However, if I try to use this with Never(), like so:

WhenSingle(m.MockedMethod()).Verify(Never())

I receive the following error when running the test:

Cause:
    expected num method calls: atLeastOnce, got: 0

This is the case whether I include a .ThenReturn() in the chain or not. Is it intentional that using Verify in this way is not compatible with Never()?

[ovechkin-dm]

Unfortunately, I cannot reproduce this behaviour.

func TestVerifyNeverInReturner(t *testing.T) {
	SetUp(t)
	m := Mock[iface]()
	WhenSingle(m.Foo(12)).Verify(Never())
	m.Foo(12)
}

Example above works as expected and fails with error:

Cause:
        	expected num method calls: 0, got : 1
        		iface.Foo(Equal(12))

Can you please provide fully reproducible example of you behaviour?

[jacksehr]

Ah, sorry, I believe this is due to the use of StrictVerify. As described in its comment:

StrictVerify enables strict verification of mock calls. This means that all mocked methods that are not called will be reported as errors...

This is what adds the atLeastOnce -- which I suppose makes it incompatible with Verify(Never()).

e.g. this passes:

func TestVerifyNeverInReturner(t *testing.T) {
	SetUp(t)
	m := Mock[iface]()
	WhenSingle(m.Foo(12)).Verify(Never())
}

While this fails:

func TestVerifyNeverInReturner(t *testing.T) {
-	SetUp(t)
+	SetUp(t, mockopts.StrictVerify())
	m := Mock[iface]()
	WhenSingle(m.Foo(12)).Verify(Never())
}

...
expected num method calls: atLeastOnce, got: 0
       		iface.Foo(Equal(12))
...

I can see how this might be a bit of an annoying edge case to support when using StrictVerify -- if this is the intentional API I'm happy to close this issue. It would be nice to be able to use both StrictVerify and Never though!

[ovechkin-dm]

I see the problem now.
I agree that the behavior should be that test like this succeeds:

func TestVerifyNeverInReturner(t *testing.T) {
	SetUp(t, mockopts.StrictVerify())
	m := Mock[iface]()
	WhenSingle(m.Foo(12)).Verify(Never())
}

The fix is made in v1.0.2
However I would encourage you to use standard api for such cases, because it removes potential ambiguity in test interpretation:

func TestVerifyNeverInReturner(t *testing.T) {
	SetUp(t, mockopts.StrictVerify())
	m := Mock[iface]()
	Verify(m, Never()).Foo(12)
}

Can you please verify that everything is working now, and close the issue?

[jacksehr]

Looks good, thanks for the quick fix! 🙂