Hi I've been using moq for a while when I see this code.
I have to setup a return in one of my repo.
mockIRole.Setup(r => r.GetSomething(It.IsAny<Guid>(), It.IsAny<Guid>(),
It.IsAny<Guid>())).Returns(ReturnSomething);
I have three parameters and I just saw these in one of articles or blog on the net.
What is the use of It.Is<>
or It.IsAny<>
for an object? if I could use Guid.NewGuid()
or other types then why use It.Is
?
I'm sorry I'm not sure if my question is right or am I missing some knowledge in testing. But it seems like there is nothing wrong either way.
4. It. IsAny<Guid>() means that you don't care what parameter was passed.
Using It.IsAny<>
, It.Is<>
, or a variable all serve different purposes. They provide increasingly specific ways to match a parameter when setting up or verifying a method.
The method set up with It.IsAny<>
will match any parameter you give to the method. So, in your example, the following invocations would all return the same thing (ReturnSomething
):
role.GetSomething(Guid.NewGuid(), Guid.NewGuid(), Guid.NewGuid());
Guid sameGuid = Guid.NewGuid();
role.GetSomething(sameGuid, sameGuid, sameGuid);
role.GetSomething(Guid.Empty, Guid.NewGuid(), sameGuid);
It doesn't matter the actual value of the Guid
that was passed.
The It.Is<>
construct is useful for setup or verification of a method, letting you specify a function that will match the argument. For instance:
Guid expectedGuid = ...
mockIRole.Setup(r => r.GetSomething(
It.Is<Guid>(g => g.ToString().StartsWith("4")),
It.Is<Guid>(g => g != Guid.Empty),
It.Is<Guid>(g => g == expectedGuid)))
.Returns(ReturnSomething);
This allows you to restrict the value more than just any value, but permits you to be lenient in what you accept.
When you set up (or verify) a method parameter with a variable, you're saying you want exactly that value. A method called with another value will never match your setup/verify.
Guid expectedGuids = new [] { Guid.NewGuid(), Guid.NewGuid(), Guid.NewGuid() };
mockIRole.Setup(r => r.GetSomething(expectedGuids[0], expectedGuids[1], expectedGuids[2]))
.Returns(ReturnSomething);
Now there's exactly one case where GetSomething
will return ReturnSomething
: when all Guid
s match the expected values that you set it up with.
If you look at the Quickstart documentation for Moq
Matching Arguments
// any value
mock.Setup(foo => foo.DoSomething(It.IsAny<string>())).Returns(true);
// matching Func<int>, lazy evaluated
mock.Setup(foo => foo.Add(It.Is<int>(i => i % 2 == 0))).Returns(true);
// matching ranges
mock.Setup(foo => foo.Add(It.IsInRange<int>(0, 10, Range.Inclusive))).Returns(true);
// matching regex
mock.Setup(x => x.DoSomething(It.IsRegex("[a-d]+", RegexOptions.IgnoreCase))).Returns("foo");
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