Moq Tips 2 - check if a log message with a specific prefix/suffix and call a method with an object having a specific field value
- To check if a log message with a specific prefix is logged, you can use Moq's Verify method along with an appropriate assertion.
_logger.Verify(logger => logger.logInformation(
It.Is<string>(s => s.StartsWith("specific prefix"))), Times.Once);
- To verify that a method is called with an object containing a specific property value, you can use Moq's
It.Is<T>
matcher along with a lambda expression. Here's an example:
_mockObject.Verify(x => x.MyMethod(It.Is<MyObject>(
obj => obj.PropertyValue == expectedPropertyValue)), Times.Once);
- Correctly returns null: Sometimes we need to set up a Moq mock to return null but cannot directly do it as Moq doesn't allow. Please check the following way that you should use:
_bookStoreAccountRepository.Setup(
b => b.GetBookStoreAccountByUserName(It.IsAny<string>()))
.Returns((BookStoreAccount)null);
The key is to use (BookStoreAccount)null
to explicitly cast null to the expected return type.