When Condition Method in Moq

Question

I am trying to figure how to use When method for my use.

When(Func<bool> condition);

Another post here has one example of usa of When method

var mockedService = new Mock<IFormatProvider>();

mockedService.When(() => DateTime.Now.Hour < 12).Setup(x => x.GetFormat(typeof(string))).Returns(null);

What I am trying to do is I have a variable called x. I want to use When method so it performs action only when X is not Null.

for example

      mockedService.When(()=> !null x).Returns(x)
      or
      mockedService.When(condition => x).Returns(x);

Both of the above lines of code are not working syntex is not correct. Any idea how to write it correctly. Thanks

Answer 1

You must Setup method to return:

mockedService.When(() => null != x)
     .Setup(s => s.GetFormat(It.IsAny<Type>()))
     .Returns(x);

Another way:

mockedService
     .Setup(s => s.GetFormat(It.Is<Type>(t => x != null)))
     .Returns(x);