How do you name your unit test methods?

Question

What is your general rule in naming your unit test methods? I am sure a lot of people out there also wonder about this question. Suppose, a method under test is

public Customer GetCustomerById(int id)

How would you name your unit test methods?

GetCustomerById?
GetCustomerByIdTest?
GetCustomerByIdShouldReturnCustomer?
GetCustomerByIdShoudReturnCustomerWhenItSucceeds?
GetCustomerByIdShouldReturnNullWhenNotFound?
Get_Customer_By_Id?

..and so on and so forth.

Any thoughts? Thanks.

Answer 1

I would suggest to use following format. This helps to know what exactly you are testing by just looking at the test method name.

[UnitOfWork_StateUnderTest_ExpectedBehavior]

GetCustomerById_WithValidId_ReturnsCustomer
GetCustomerById_WithInvalidId_ReturnsNull

This is using Roy Oshrove's suggested naming standard: http://osherove.com/blog/2005/4/3/naming-standards-for-unit-tests.html