Refactoring our test class to use MockRepository

introducing-mockrepository.cs

using NUnit.Framework;
using Moq;

[TestFixture]
public class ReallyHardToTestTests{
  MockRepository mockRepository = new MockRepository(MockBehavior.Strict);

  Mock<IPathWrapper> mockPathWrapper;
  Mock<ISomeOtherDependency> mockSomeOtherDependency;
  Mock<ISomeModelFactory> mockSomeModelFactory;
  SomeModel someModel;
  
  ReallyHardToTest systemUnderTest;
  
  [SetUp]
  public void SetUp(){
    mockPathWrapper = mockRepository.Create<IPathWrapper>();
    mockSomeOtherDependency = mockRepository.Create<ISomeOtherDependency>();
    mockSomeOtherDependency.Setup(p=>p.DoSomething());
    
    mockSomeModelFactory = mockRepository.Create<ISomeModelFactory>();
    someModel = new SomeModel();
    mockSomeModelFactory.Setup(p=>p.Create()).Returns(someModel);
    
    systemUnderTest = new ReallyHardToTest(mockSomeOtherDependency.Object, mockPathWrapper.Object, mockSomeModelFactory.Object);
  }
  
  [TestCase(@"c:\some\path\filename.txt", "filename.txt")]
  [TestCase(@"c:\some\really\long\path\otherFile.txt", "otherFile.txt")]
  public void SetFilename_Always_InvokesPathGetFileName(string input, string expectedFilename){
    // Configure our mock expectations
    mockPathWrapper.Setup(p=>p.GetFileName(input)).Returns(expectedFilename);
    
    // Exercise our method under test
    SystemUnderTest.SetFilename(input);
    
    // Verify that our mock's expectations were met
    mockRepository.VerifyAll();
    Assert.That(someModel.Filename, Is.EqualTo(expectedFilename));
  }
  
  [Test]
  public void Constructor_Always_PerformsExpectedWork(){
    // We're testing the constructor, so no Arrange step here.
    // Likewise with Act - creating our SystemUnderTest is the 
    // Act we're testing here.
    
    mockRepository.VerifyAll();
  }
}