nunit-isolation enables running every nunit test in a separate process or appdomain. The motivation is to enable UI-component testing in the same way as you test model and workflow classes: you need to isolate the component under test, mock dependencies, perform a few actions and finally assert the resulting state. Without isolating the UI display and automation in a separate appdomain or process, it is impossible to keep a stable state from test to test.

This project is inspirated from the project NUnit.ApplicationDomain (https://www.nuget.org/packages/NUnit.ApplicationDomain). It re-uses the ability of executing the test in a separate app-domain. The usage has been extended to be able to execute the test in a separate process.

Executing a test in separate app-domain has the drawback that you cannot ensure that the app-domain is succesfully unloaded at the end (AppDomain.Unload() throws an exception if any foreground thread remains in the AppDomain). That's why you sometimes need a full isolation by running each test in a separate process...

On the other side, it is easier to debug test within a single process, as tools like NUnit debugger attach automatically to the testing-process.

See the unit test class 'IsolationTest'

[Test]
public void AppDomainTest()
{
	// re-run the test in a separate app-domain
	Api.Isolation.ReRun(Isolations.AppDomain);
	
	// todo test here
}

See the unit test class 'IsolationAttributeTest'

[Test, Isolation(Isolations.Process)]
public void AppDomainTest()
{
	// todo test here
}

While developing or fixing unit test, you may need to attach visual studio debugger to the test running in a separate process. Here is how you can attach the debugger by changing the test configuration.

[Test]
public void AppDomainTest()
{
	Api.Isolation.ReRun(Isolations.AppDomain, true /*attachDebugger*/);
//...		
}

[Test, Isolation(Isolations.Process, true /*attachDebugger*/)]
public void AppDomainTest()
{
	// todo test here
}

• get source
• replace the third-party nunit framework library
• compile with the required platform AnyCPU or x86
• add compilation result to your test project
• add annotation or re-run command to your test
• enjoy