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I'm having a go with the TestCaseSource attribute. One problem: when the sourceName string is invalid, the test just gets ignored instead of failing. This would be really bad if the source method gets renamed, the sourceName string doesn't get updated, and then you lose the coverage that the test provided. Is there a way to change the behaviour of NUnit, so that the test fails if the sourceName is invalid?
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TestCaseSourceAttribute is used on a parameterized test method to identify the source from which the required arguments will be provided. The attribute additionally identifies the method as a test method. The data is kept separate from the test itself and may be used by multiple test methods.
All of the built-in attributes allow for data to be provided programmatically, but NUnit does not have any attributes that fetch the data from a file or other external source.
There are other NUnit attributes that enable you to write a suite of similar tests. A [TestCase] attribute is used to create a suite of tests that execute the same code but have different input arguments. You can use the [TestCase] attribute to specify values for those inputs.
If you add a second parameter with the Values attribute, for per value of the first parameter, NUnit will add a test for every value of the second parameter. Another way to avoid having to write duplicate tests when testing the same behaviour with different inputs is to use TestCase attribute on the test itself.
This is resolved in NUnit 2.6.2. There is a new constructor for the attribute that takes a Type (which must implement IEnumerable); it "is recommended for use in preference to other forms because it doesn't use a string to specify the data source and is therefore more easily refactored." (From the documentation.)
This does require that your test runner supports the latest NUnit.
A very basic example (see the above documentation link for more details):
public class TestDataProvider : IEnumerable { public IEnumerator GetEnumerator() { return new List<int>{ 2, 4, 6 }.GetEnumerator(); } } [TestFixture] public class MyTests { [TestCaseSource(typeof(TestDataProvider))] public void TestOne(int number) { Assert.That(number % 2, Is.EqualTo(0)); } } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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