Testable factory

TestableFactory.cs

/*
	NEW STRUCTURE OF THE FACTORY
		- No longer static
		- Uses interface so we can mock response
*/
public interface IDriverFactory { IDriver CreateDriver(DriverType driverType, string ip); }
public class DriverFactory : IDriverFactory
{
	public IDriver CreateDriver(DriverType driverType, string ip)
	{
		//Do some work here to create driver
	}
}

/*
	SYSTEM UNDER TEST (sut)
		- Uses IDriverFactory instance to generate driver
		- We can test this now
*/
public class IOTest 
{
	IDriver _driver;

	public IOTest(IDriverFactory driverFactory, DriverType driverType, string ip)
	{
		_driver = driverFactory.CreateDriver(driverType, ip);
		.
		.
		.
	}

	public void Execute()
	{
		_driver.ReadData();
		.
		.
		.
	}
}

/*
	NUNIT TEST FIXTURE
		- Creates Mock IDriver/IDriverFactory
		- Allows us to control the response of a mock driver, 
		  testing the Execute method's logic in a very controlled way
*/
[TestFixture]
public class SomeTestClass()
{
	[Test]
	public void should_create_test_with_mock_driverfactory()
	{
		//Arrange
		DriverType testType = DriverType.S71200;
		string ipAddress = "127.0.0.1";

		IDriver mockDriver = MockRepository.GenerateMock<IDriver>();
		Expect.Call(mockDriver.ReadData()).Return(new byte[] { 0,1,2,3,4 });

		IDriverFactory mockFactory = MockRepository.GenerateMock<IDriverFactory>();
		Expect.Call(mockFactory.CreateDriver(testType, ipAddress)).Return(mockDriver);

		IOTest sut = new IOTest(mockFactory, testType, ipAddress);

		//Act
		sut.Execute();

		//Assert
		/* Assert methods in driver were called, or the state of some properties of IOTest (not written here) */
	}

}