MsTest ClassInitialize and Inheritance

I have a base class for my tests which is composed in the following way:

[TestClass]
public abstract class MyBaseTest
{
   protected static string myField = "";

   [ClassInitialize]
   public static void ClassInitialize(TestContext context)
   {
       // static field initialization
       myField = "new value";
   }
}

Now I am trying to create a new test that inherits from the base, with the following signature:

[TestClass]
public class MyTest : MyBaseTest
{
   [TestMethod]
   public void BaseMethod_ShouldHave_FieldInitialized()
   {
       Assert.IsTrue(myField == "new value");
   }
}

The ClassInitialize is never called by the child tests ... What is the real and correct way of using test initialization with inheritance on MsTest?

Solution 1:

Unfortunately you cannot achieve this that way because the ClassInitializeAttribute Class cannot be inherited.

An inherited attribute can be used by the sub-classes of the classes that use it. Since the ClassInitializeAttribute cannot not be inherited, when the MyTest class is initialized the ClassInitialize method from the MyBaseTest class cannot be called.

Try to solve it with another way. A less efficient way is to define again the ClassInitialize method in MyTest and just call the base method instead of duplicating the code.

Solution 2:

A potential workaround is to define a new class with AssemblyInitializeAttribute instead. It has a different scope, obviously, but for me it meets my needs (cross-cutting concerns, which just so happen to require exactly the same settings for every test class and test method.)

using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace MyTests
{
  [TestClass]
  public sealed class TestAssemblyInitialize
  {
    [AssemblyInitialize]
    public static void Initialize(TestContext context)
    {
      ...
    }
  }
}