A common challenge when writing unit tests for a large code base is keeping track of what you are testing. Without a good process for categorizing what the individual tests are actually testing, it can quickly become unmanageable. This is especially true for projects with several hundred tests.
The way I have decided to tackle this challenge in ExpressUnit is through use cases. For those of you unfamiliar with the concept of use cases, here’s the Wikipedia definition:
“A use case in software engineering and systems engineering is a description of a system’s behavior as it responds to a request that originates from outside of that system. In other words, a use case describes “who” can do “what” with the system in question. The use case technique is used to capture a system’s behavioral requirements by detailing scenario-driven threads through the functional requirements.”
Source: http://en.wikipedia.org/wiki/Use_case
Since use cases are a description of how the system should behave, I find them to be a very natural grouping for unit/integration tests. The mechanism for grouping tests by use cases in ExpressUnit is actually quite simple. I have simply extended the test attributes (UnitTest/IntegrationTest) to take in an optional use case parameter. The new syntax works as follows:
[UnitTest(UseCase="Confirm.Equals will return true if objects are equal")]
public void ConfirmDoubleObjectsAreEqualTests()
{
Confirm.Equals(1.0, 1.0);
}
The above example is from ExpressUnit’s own Confirm test suite where all Confirm.Equals tests have been linked to the use case: “Confirm.Equals will return true if objects are equal”.
Version 3.2 of ExpressUnit contains a new UI window for displaying test results broken down by use cases. (See Figure1). You can navigate to this window by clicking the Use Case tab after running all your tests.
Figure1
Tags: ExpressUnit, TDD, unit tests, Unit Tests Use Cases
