Initialization and Cleanup (Assembly, Class, Test)

Overview

There are six attributes you can use to perform initialization and cleanup. Which ones you use, depends on when you need to initialize something and/or clean something up. You can initialize/cleanup once for all classes within a unit test assembly. You can initialize/cleanup once for all test methods within a test class. You can initialize/cleanup before and after each test method runs within a class.

• AssemblyInitialize

• AssemblyCleanup

• ClassInitialize

• ClassCleanup

• TestInitialize

• TestCleanup

Add one or more of these attributes to a single method within your classes. You can see an example of how these attributes might be applied to a set of classes in your assembly displayed in Figure 1.

Figure 1: Overview of how test initialization and cleanup methods execute

Assembly Initialization and Clean Up

If you have several classes within a specific assembly and you need to create a database with some test records in some tables prior to running all, or the majority, of tests within these classes, create that database within a method decorated with the [AssemblyInitialize] attribute.

Only one method within your entire assembly may be decorated with the [AssemblyInitialize] attribute. This method must be static and the test framework will pass in an instance of the TestContext object.

[AssemblyInitialize()]
public static void AssemblyInitialize(TestContext tc) 
{
    // TODO: Initialize for all tests within an assembly 
    tc.WriteLine(“In AssemblyInitialize”);
}

Class Initialization and Clean Up

Just as you create classes in your application to encapsulate a specific set of functionality, organize your unit test classes the same way. Only one method within your test class may be decorated with the [ClassInitialize] attribute.

[ClassCleanup()]
public static void ClassCleanup() 
{ // TODO: Clean up after all tests within this class
}

Test Initialization and Clean Up

The method decorated with the [ClassInitialize] attribute only runs once the first time a class is created. A method decorated with the [TestInitialize] attribute will run before each test method within that class. If you have four methods in a test class, the TestInitialize method will run four times. As an example, if you need a specific file name to exist before all, or the majority, of tests within a class are run, create a method like the one shown below.

[TestInitialize()]
public void TestInitialize() 
{
  // Create the Test.txt file.
  File.AppendAllText("Test.txt", "Some Text");
}