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c#nunittestcasebase-class
Mark Lisoway
Mark Lisoway

Reputation: 629

NUnit TestCaseSource in base class with data from derived class

I am wondering if there is a way to use TestCaseSource in a base test class with data given from the derived class in a generic way.

For example, if I had the following base class:

public abstract class Base<T>
{
    protected static T[] Values;

    [TestCaseSource(nameof(Values))]
    public void MyTest(T[] values)
    {
        // Some test here with the values;
    }

}

And the following derived class

[TestFixture]
public class Derived : Base<string>
{

    [OneTimeSetup]
    public void OneTimeSetup()
    {
        Values = new[] { "One", "Two" };
    }

    [TestCaseSource(nameof(Values))
    public void DerivedSpecificTest(T[] values)
    {
        // Some test here with the values;
    }

}

I assume what I am doing is incorrect, because, when I run the derived class tests, I get this exception on both tests: Failed: System.Exception: The test case source could not be found.

However, the example should get across what I am trying to do (if what I am trying to is possible). Essentially I am wondering if it is possible to use TestCaseSource in the base class with data given from the derived class.

Any help is appreciated, and I can answer questions if clarity is needed.

I should also mention that if I initialize Values to an empty, zero length array, the tests return as inconclusive. I assume this is because the data changes while the tests are being created (some behavior with NUnit?).

And I can get the tests to run if I don't use TestCaseSource, but instead just mark the tests with the attribute Test, and insert my test logic into a loop with each array value. This is not ideal as when a test fails, it is difficult to see exactly which input caused it to fail, because, each input is not separated out.

Upvotes: 2

Views: 1271

Answers (1)

Stephen Straton
Stephen Straton

Reputation: 739

This should get you started, no doubt there is a more elegant solution. 

using System;
using NUnit.Framework;

namespace UnitTestProject1
{
    public class Base<T>
    {
        private static T[] Values;

        [TestCaseSource(nameof(Values))]
        public void MyTest(T value)
        {
            Console.WriteLine($"Base: {value}");
            // Some test here with the values;
        }
    }

    [TestFixture]
    public class Derived : Base<string>
    {
        private static string[] Values= new[] { "One", "Two" };

        [TestCaseSource(nameof(Values))]
        public void DerivedSpecificTest(string value)
        {
            // Some test here with the values;
            Console.WriteLine($"Derived: {value}");
        }
    }
}

Upvotes: 3

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