Question

What are the best practices for naming unit test classes and test methods?

This was discussed on SO before, at What are some popular naming conventions for Unit Tests?

I don’t know if this is a very good approach, but currently in my testing projects, I have one-to-one mappings between each production class and a test class, e.g. Product and ProductTest.

In my test classes I then have methods with the names of the methods I am testing, an underscore, and then the situation and what I expect to happen, e.g. Save_ShouldThrowExceptionWithNullName().

Answer 1

Update (Jul 2021)

It’s been quite a while since my original answer (almost 12 years) and best practices have been changing a lot during this time. So I feel inclined to update my own answer and offer different naming strategies to the readers.

Many comments and answers point out that the naming strategy I propose in my original answer is not resistant to refactorings and ends up with difficult to understand names, and I fully agree.

In the last years, I ended up using a more human readable naming schema where the test name describes what we want to test, in the line described by Vladimir Khorikov.

Some examples would be:

• Add_credit_updates_customer_balance
• Purchase_without_funds_is_not_possible
• Add_affiliate_discount

But as you can see it’s quite a flexible schema but the most important thing is that reading the name you know what the test is about without including technical details that may change over time.

To name the projects and test classes I still adhere to the original answer schema.

Original answer (Oct 2009)

I like Roy Osherove’s naming strategy. It’s the following:

[UnitOfWork_StateUnderTest_ExpectedBehavior]

It has every information needed on the method name and in a structured manner.

The unit of work can be as small as a single method, a class, or as large as multiple classes. It should represent all the things that are to be tested in this test case and are under control.

For assemblies, I use the typical .Tests ending, which I think is quite widespread and the same for classes (ending with Tests):

[NameOfTheClassUnderTestTests]

Previously, I used Fixture as suffix instead of Tests, but I think the latter is more common, then I changed the naming strategy.