File this one under "old features I'm only now learning about." It seems NUnit has had a RowTest extension built in since March of 08...
For example, let's say I have a method called Add that adds two integers and returns the result. (The internals of that method are highly complex and I won't go into details here.) If you wanted to test two positive integers, a unit test would look like this:
[Test]
public void AddTwoPositiveNumbers()
{
Assert.AreEqual(2 + 3, Add(2, 3),
"Add returned incorrect result");
}
To test two negative integers you would historically create a second, nearly identical unit test:
[Test]
public void AddTwoNegativeNumbers()
{
Assert.AreEqual(-1 + -4, Add(-1, -4),
"Add returned incorrect result");
}
For reference, the two tests will appear under the class name when viewed through the NUnit GUI.
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Now, these don't seem too bad, but what happens if you needs lots of nearly-identical tests? Or these tests need to perform additional steps? Copy/paste is a bad programming practice, even for unit tests. Fortunately, Nunit provides an extension (under the NUnit.Framework.Extensions namespace not surprisingly) that makes life much easier - the RowTest.
To use, create a single test method with parameters for the varying test data. Decorate the method with a RowTest attribute, and one Row attribute for each test case. The above unit tests can now be replaced by:
[RowTest]
[Row(2, 3)]
[Row(-1, -4)]
public void AddTwoNumbers(int x, int y)
{
Assert.AreEqual(x + y, Add(x, y),
"Add returned incorrect result");
}
Changes to the test set becomes much easier, as does adding new tests. In the GUI, you'll see each Row split out as an individual test beneath the generic test:
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