NUnit parameterized tests with datetime

nunitunit testing

Is it not possible with NUnit to go the following?

[TestCase(new DateTime(2010,7,8), true)]
public void My Test(DateTime startdate, bool expectedResult)
{
    ...
}

I really want to put a datetime in there, but it doesn't seem to like it. The error is:

An attribute argument must be a constant expression, typeof expression
or array creation expression of an attribute parameter type

Some documentation I read seems to suggest you should be able to, but I can't find any examples.

Best Answer

You can specify the date as a constant string in the TestCase attribute and then specify the type as DateTime in the method signature.

NUnit will automatically do a DateTime.Parse() on the string passed in.

Example:

[TestCase("01/20/2012")]
[TestCase("2012-1-20")] // Same case as above in ISO 8601 format
public void TestDate(DateTime dt)
{
    Assert.That(dt, Is.EqualTo(new DateTime(2012, 01, 20)));
}

Related Solutions

What are unit tests, integration tests, smoke tests, and regression tests?

Unit test: Specify and test one point of the contract of single method of a class. This should have a very narrow and well defined scope. Complex dependencies and interactions to the outside world are stubbed or mocked.
Integration test: Test the correct inter-operation of multiple subsystems. There is whole spectrum there, from testing integration between two classes, to testing integration with the production environment.
Smoke test (aka sanity check): A simple integration test where we just check that when the system under test is invoked it returns normally and does not blow up.
- Smoke testing is both an analogy with electronics, where the first test occurs when powering up a circuit (if it smokes, it's bad!)...
- ... and, apparently, with plumbing, where a system of pipes is literally filled by smoke and then checked visually. If anything smokes, the system is leaky.
Regression test: A test that was written when a bug was fixed. It ensures that this specific bug will not occur again. The full name is "non-regression test". It can also be a test made prior to changing an application to make sure the application provides the same outcome.

To this, I will add:

Acceptance test: Test that a feature or use case is correctly implemented. It is similar to an integration test, but with a focus on the use case to provide rather than on the components involved.
System test: Tests a system as a black box. Dependencies on other systems are often mocked or stubbed during the test (otherwise it would be more of an integration test).
Pre-flight check: Tests that are repeated in a production-like environment, to alleviate the 'builds on my machine' syndrome. Often this is realized by doing an acceptance or smoke test in a production like environment.

C# – How to set DateTime as ValuesAttribute to unit test

An alternative to bloating up your unit test, you can offload the creation of the TestCaseData using the TestCaseSource attribute.

TestCaseSource attribute lets you define a method in a class that will be invoked by NUnit and the data created in the method will be passed into your test case.

This feature is available in NUnit 2.5 and you can learn more here...

[TestFixture]
public class DateValuesTest
{
    [TestCaseSource(typeof(DateValuesTest), "DateValuesData")]
    public bool MonthIsDecember(DateTime date)
    {
        var month = date.Month;
        if (month == 12)
            return true;
        else
            return false;
    }

    private static IEnumerable DateValuesData()
    {
        yield return new TestCaseData(new DateTime(2010, 12, 5)).Returns(true);
        yield return new TestCaseData(new DateTime(2010, 12, 1)).Returns(true);
        yield return new TestCaseData(new DateTime(2010, 01, 01)).Returns(false);
        yield return new TestCaseData(new DateTime(2010, 11, 01)).Returns(false);
    }
}

Best Answer

Related Solutions

What are unit tests, integration tests, smoke tests, and regression tests?

C# – How to set DateTime as ValuesAttribute to unit test

Related Topic