Unit testing mock objects- How to Unit Test .NET-Mock Framework C# VB ASP.NET

Learn>Examples

Examples - How Tos

Summary

The following examples show you how to implement Typemock Isolator in your software code and write your unit tests faster and easier.

Section 1 – Mock Patterns

Basic .NET mock patterns

Using test decorators and Natural Mocks™

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 
      using (RecordExpectations recorder = RecorderManager.StartRecording()) 
      {
        // Record methods here
      } 
      // Run Test

      // Optional assertions
      Assert.AreEqual();
    }
}

Using test decorators and Reflective Mocks

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 

      // Run Test

      // Optional assertions
      Assert.AreEqual();
    }
}

Mocking one instance - Mocking .NET code

Using Natural Mocks™

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 
      using (RecordExpectations recorder = RecorderManager.StartRecording()) 
      {
        // Record methods here
		   ClassToIsolate mockedInstance = new ClassToIsolate();
		   mockedInstance.Method();
      } // END RECORD STAGE

      // Run Test
      ClassUnderTest test = new ClassUnderTest();
	     test.RunMethod();
      // These statements are run in RunMethod()
      //-  ClassToIsolate mockedInstance = new ClassToIsolate();
      //-  mockedInstance.Method();
   }
}

Using Reflective Mocks

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 
	     Mock mock = MockManager.Mock<ClassToIsolate>();
      mock.ExpectCall("Method");

      // Run Test
      ClassUnderTest test = new ClassUnderTest();
	     test.RunMethod();
      // These statements are run in RunMethod()
      //-  ClassToIsolate mockedInstance = new ClassToIsolate();
      //-  mockedInstance.Method();
    }
}

Mocking a type (all instances)

Using Natural Mocks™

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 
      using (RecordExpectations recorder = RecorderManager.StartRecording()) 
      {
        recorder.MockAllInstances = true;
        ClassToIsolate mockedInstance = new ClassToIsolate();
		 mockedInstance.Method();
        recorder.RepeatAlways();
      } // END RECORD STAGE

      // Run Test
      ClassUnderTest test = new ClassUnderTest();
	     test.RunMethod();
      // Multiple 'new' run in RunMethod() 
      //-  ClassToIsolate mockedInstance = new ClassToIsolate();
      //-  mockedInstance.Method();
 	 //-  ClassToIsolate mockedInstance2 = new ClassToIsolate();
      //-  mockedInstance2.Method();
   }
}

Using Reflective Mocks

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 
	     Mock mock = MockManager.MockAll<ClassToIsolate>();
      mock.ExpectCall("Method");

      // Run Test
      ClassUnderTest test = new ClassUnderTest();
	     test.RunMethod();
      // Multiple 'new' run in RunMethod() 
      //-  ClassToIsolate mockedInstance = new ClassToIsolate();
      //-  mockedInstance.Method();
 	 //-  ClassToIsolate mockedInstance2 = new ClassToIsolate();
      //-  mockedInstance2.Method();
    }
}

Creating a mocked object from an interface/abstract class

Using Natural Mocks™

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 
      IInterfaceToMock mockedInterface = RecorderManager.CreateMockedObject<IIsolated>();
      using (RecordExpectations recorder = RecorderManager.StartRecording()) 
      {
         // Record Method by using mockedInterface
		    mockedInterface.Method();
      } 

      // Run Test (pass mockedInterface)
      ClassUnderTest test = new ClassUnderTest(mockedInterface);
	     test.RunMethod();
   }
}

Using Reflective Mocks

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 
	     MockObject<IInterfaceToMock> mockInterface = MockManager.MockObject<IInterfaceToMock>();
      mockInterface.ExpectCall("Method");

      // Run Test (pass mockInterface)
      ClassUnderTest test = new ClassUnderTest(mockInterface.Object);
	     test.RunMethod();
   }
}

Stubbing a type

Using Natural Mocks™

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 
      using (RecordExpectations recorder = RecorderManager.StartRecording()) 
      {
	        recorder.VerifyMode = VerifyMode.PassIfNotCalled;
         // Record methods here
      } 

      // Run Test 
      ClassUnderTest test = new ClassUnderTest();
	     test.RunMethod();
   }
}

Using Reflective Mocks

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithMock()
   { 
      // Setup mocks 
      Mock mock = MockManager.Mock<ClassToIsolate>();
      m.StartBlock(VerifyMode.PassIfNotCalled);
      // Set Expectation here 
      m.EndBlock();
	  
      // Run Test 
      ClassUnderTest test = new ClassUnderTest();
	     test.RunMethod();
   }
}

Testing asynchronous code

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks(Timeout=4000)] // Verify that all expected calls where made 
   public void TestWithMock()
   { 
      // Setup mocks and Run Test 
   }
}

Section 2 – Faking Method Calls

Mocking a public static method

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod();
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock<ClassToIsolate>();
     mock.ExpectCall("StaticMethod");
   }

}

Mocking a public instance method

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate mockedInstance = new ClassToIsolate();
	   mockedInstance.InstanceMethod();
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock<ClassToIsolate>();
     mock.ExpectCall("InstanceMethod");
   }
}

Mocking a private method

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock<ClassToIsolate>();
     mock.ExpectCall("PrivateMethod");
   }
        
   [DeploymentItem("HowTo.exe")] 
   [TestMethod]
   [VerifyMocks]
   public void TestWithNatural_VisualStudioAccessors()
   {
     object target = PrivateMethods.ClassToIsolateAccessor.CreatePrivate();
     PrivateMethods.ClassToIsolateAccessor accessor = new PrivateMethods.MClassToIsolateAccessor(target);            

     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {

	   accessor.PrivateMethod();
     }            
   }
}

Mocking properties

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate mockedInstance = new ClassToIsolate();
	   mockedInstance.MyProperty = 6;
       recorder.ExpectAndReturn(mockedInstance.MyProperty, 5);

     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock<ClassToIsolate>();
	 mock.ExpectSet("MyProperty");
     mock.ExpectGet("MyProperty", 5);

   }
}

Mocking indexers

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate mockedInstance = new ClassToIsolate();
	   mockedInstance[5] = "any-value";
       recorder.ExpectAndReturn(mockedInstance[5], "fake-value");
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock<ClassToIsolate>();
	 mock.ExpectSetIndex();
     mock.ExpectGetIndex("fake-value");

   }
}

Mocking generics

Mocking a specific generic type

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate<int> mockedInstance = new ClassToIsolate<int>();
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock<ClassToIsolate<int>();
	  }
}

Mocking unspecified (all) generic types

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock(typeof(GenericClassToIsolate));
	  }
}

Mocking a specific generic method

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate mockedInstance = new ClassToIsolate();
       mocked.GenericMethod<int>();   
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock<ClassToIsolate>();
     mock.ExpectCall("GenericMethod", Generic.Method<int>());
	  }
}

Mocking unspecified (all) generic methods

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock(typeof(ClassToIsolate));
     mock.ExpectCall("GenericMethod");
	  }
}

Mocking and firing events

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
      View fakeView = RecorderManager.CreateMockedObject<View>();
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
        fakeView.Changed += null;
     }
     // Wire View to model
     model.SetView(fakeViewMock.Object);
     // Fire Changed event we can test if our model reacts to event
     RecorderManager.LastMockedEvent.Fire(this, null);
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     MockObject<View> fakeViewMock = MockManager.MockObject<View>();
     MockedEvent handle = fakeViewMock.ExpectAddEvent("Changed");

     // Wire View to model
     model.SetView(fakeViewMock.Object);
     // Fire Changed event we can test if our model reacts to event
     handle.Fire(this, null);
  }
}

Section 3 – Setting Expectations

Returning fake values

Setting return values

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod();
       recorder.Return("fake-value");
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
	     Mock mock = MockManager.MockAll<ClassToIsolate>();
      mock.ExpectAndReturn("StaticMethod", "fake-value");
	  }
}

Repeating return values

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod();
       recorder.Return("fake-value").Repeat(3);
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
	  Mock mock = MockManager.MockAll<ClassToIsolate>();
      mock.ExpectAndReturn("StaticMethod", "fake-value", 3 /* repeat */);
   }
}

Returning values regardless of the number of times the method was called (stub)

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod();
       recorder.Return("fake-value").RepeatAlways();
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
	  Mock mock = MockManager.MockAll<ClassToIsolate>();
      mock.AlwaysReturn("StaticMethod", "fake-value");
   }
}

Returning values of out and ref arguments

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     string fakeOutValue = "fake-out-value";
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod(out fakeOutValue);
       recorder.Return("fake-value");
     }  
     //Test Execution     
     string OutValue = "supplied-out-value";
     ClassToIsolate.StaticMethod(outValue); 
     Assert.AreEqual("fake-out-value",outValue); //will succeed 
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock(typeof(ClassToIsolate));
     mock.ExpectAndReturn("StaticMethod", "fake-value").Args(new Assign("fake-out-value"));
     //Test Execution
     string OutValue = "supplied-out-value";
     ClassToIsolate.StaticMethod(outValue); 
     Assert.AreEqual("fake-out-value",outValue); //will succeed 
   }
}

Returning dynamic values that change

[TestFixture]
[ClearMocks]
public class TestClass
{     
   public static object MyReturnValue(object[] parameters, object context)
   {
     // Logic goes here
     if ((bool)parameters[0] == false)
     {
        return 0;
     }
     return 1;
   }

   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod();
       recorder.Return(new DynamicReturnValue(MyReturnValue));
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock(typeof(ClassToIsolate));
     mock.ExpectAndReturn("StaticMethod", new DynamicReturnValue(MyReturnValue));
	  }
}

Injecting faults

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod();
       recorder.Throw(new NullReferenceException());
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock<ClassToIsolate>();
     mock.ExpectAndThrow("StaticMethod", new NullReferenceException()); 
   }
}

Validating arguments of mocked methods

Checking the values of arguments passed

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod(5,6);
       recorder.CheckArguments();
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
	     Mock mock = MockManager.MockAll<ClassToIsolate>();
      mock.ExpectCall("StaticMethod").Args(5, 6); 
	  }
}

Using other constraints to check the arguments passed

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod("");
       recorder.CheckArguments(Check.IsEqualIgnoreCase("typemock"));
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
	  Mock mock = MockManager.MockAll<ClassToIsolate>();
      mock.ExpectCall("StaticMethod").Args(Check.IsEqualIgnoreCase("typemock"));
   }
}

Checking ref arguments

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     string fakeOutValue = "fake-out-value";
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod(ref fakeOutValue);
       recorder.Return("fake-value").CheckArguments("in-value");
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock(typeof(ClassToIsolate));
     mock.ExpectAndReturn("StaticMethod", "fake-value").
       Args(new Assign("fake-out-value")).AndCheck("in-value");
	  }
}

Checking arguments without faking the method

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod(5,6);
       recorder.CallOriginal().CheckArguments();
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
	  Mock mock = MockManager.MockAll<ClassToIsolate>();
      mock.ExpectUnmockedCall("StaticMethod").Args(5, 6); 
   }
}

Faking calls based on arguments

[TestFixture]
[ClearMocks]
public class TestClass
{
   [Test]
   [VerifyMocks]
   public void TestWithNatural()
   {
     using (RecordExpectations recorder = RecorderManager.StartRecording()) 
     {
       ClassToIsolate.StaticMethod(5);
       recorder.Return(3).WhenArgumentsMatch();

       ClassToIsolate.StaticMethod(10);
       recorder.Return(4).WhenArgumentsMatch();
     }            
   }

   [Test]
   [VerifyMocks]
   public void TestWithReflective()
   {
     Mock mock = MockManager.Mock<ClassToIsolate>();
     mock.ExpectAndReturn("StaticMethod", 3).When(5);
     mock.ExpectAndReturn("StaticMethod", 4).When(10);
   }
}

Section 4 – Operability

Running Typemock Isolator with nunit-gui and using Typemock Runner

[TypemockPath]\TMockRunner.exe [NunitPath]\bin\nunit.exe test-assembly
Alternative way see Adrian suggestion

Running using NANT

<?xml version="1.0"?> 
<project name="Typemock Examples" default="test" basedir="."> 
   <property name="nunit" value="C:\Program Files\NUnit\bin\nunit-console.exe" />
   <property name="typemock.dir" value="C:\Program Files\Typemock\Typemock Isolator" /> 

   <target name="test"> 
       <!-- Dynamically load Isolator task. -->
       <loadtasks assembly="${typemock.dir}\Typemock.NAntBuild.dll" /> 
       <Typemock Isolatortart/> 
          <exec program="${nunit}" failonerror="false"> 
             <arg value="Tests.dll" /> 
          </exec> 
       <Typemock Isolatortop/> 
   </target> 
</project>

Running using MSBuild

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> 
  <PropertyGroup> 
    <TypemockLocation>C:\Program Files\Typemock\Typemock.NET</TypemockLocation>
    <NUnit>"C:\Program Files\NUnit\bin\nunit-console.exe"</NUnit> 
  </PropertyGroup> 

  <Import Project ="$(TypemockLocation)\MSBuildSchema\Typemock.MSBuild.Tasks"/> 
  <Target Name="TestWithTypemock">
    <Typemock Isolatortart/>
    <Exec ContinueOnError="true" Command="$(NUnit) Test.dll"/> 
    <Typemock Isolatortop/> 
  </Target>
</Project>

For more information, see the Developers Guide.
Isolation: Writing Unit Tests with Isolator.
To download Typemock Isolator visit our Download page.

Learn More

Back to Learn
Download Typemock Isolator and try it
See the Developers Guide
Register to obtain a FREE Typemock account

Promote Typemock

Put the Verified with Typemock logo on your Site