First Mock

When a type is mocked, all instances of the type will have the ability to intercept its methods. This ability can be used when you want to test that a certain method was called but you do not actually want to run the code in that method.

Example - Simple Mocking

In this example, an Authentication class internally calls a Logger. You want to mock the Logger (i.e., intercept the calls and not run the original code) and verify that it was called the correct amount of times.

// C#
public bool IsAuthenticated(string name,string password)
{
      Logger.Log(Logger.NORMAL,"Entering Authentication");
      try
      {
            // do something
            int Results = DoSelect(statement);
            bool isOk = Results==1;
            if (isOk)
            {
                  Logger.Log(Logger.NORMAL,"User Authenticated "+name);
            }
            else
            {
                  Logger.Log(Logger.SECURITY,"User login failed "+name);
            }
            return isOk;
      }
      catch (Exception ex)
      {
            Logger.Log(Logger.FAILED,"Login system failure",ex);
            // handle exception
      }
}

' Visual Basic
Public Function IsAuthenticated(name As String,password As String) As Boolean
      Logger.Log(Logger.NORMAL,"Entering Authentication")
      Try
            ' do something
            Dim Results As Integer = DoSelect(statement)
            Dim isOk As Boolean = Results = 1
            If isOk Then
                  Logger.Log(Logger.NORMAL,"User Authenticated "+name)
            Else
                  Logger.Log(Logger.SECURITY,"User login failed "+name)
            End If
            IsAuthenticated = isOk
      Catch ex As Exception
            Logger.Log(Logger.FAILED,"Login system failure",ex);
            ' handle exception
      End Try
End Function

// C#
[Test] public void Authenticated ()
{
      Authentication authenticator = new Authentication();
      // Initialize Type Mocks (This can be done in the [Setup])
      MockManager.Init ();
      // the Logger class is now being mocked
    1 Mock logMock = MockManager.Mock(typeof(Logger));
      // set up our expectations for 2 Log calls in IsAuthenticated
      // 1) "Entering Authentication" Log at first line
      // 2) "User login failed user" Log
    2 logMock.ExpectCall("Log");
      logMock.ExpectCall("Log");

      // authentication should fail
      Assert.IsFalse(authenticator.IsAuthenticated("user","password"));
      // Verify that all calls were made (This can be done in the [Teardown])
   3 MockManager.Verify();
}

' Visual Basic
<Test()> Public Sub Authenticated ()
      Dim authenticator As Authentication = new Authentication
      ' Initialize Type Mocks (This can be done in the <Setup>)
      MockManager.Init()
      ' the Logger class is now being mocked
    1 Dim logMock As Mock = MockManager.Mock(GetType(Logger))
      ' set up our expectations for 2 Log calls in IsAuthenticated
     ' 1) "Entering Authentication" Log at first line
      ' 2) "User login failed user" Log
    2 logMock.ExpectCall("Log")
      logMock.ExpectCall("Log")

      ' authentication should fail
      Assert.IsFalse(authenticator.IsAuthenticated("user","password"))
      ' Verify that all calls were made (This can be done in the <Teardown>)
   3 MockManager.Verify()
End Sub

To run the example, you can type in the following: tmockRunner nunit-console.exe test.dll.

To set the expectation for more than one call, use the timesToRun parameter, so that the code in 2 above is equivalent to logMock.ExpectCall("Log",2).

	1 Mock the class.
	2 Intercept the method (this phase is called Expectations, as you tell Typemock Isolator what calls you expect).
	3 Verify that all expected methods were called (this acts the same as regular mock objects).

	1	Set up mocking of the Logger; the next new Logger instance will be mocked and all static calls will be intercepted. In this case, the logger's static method IsAuthenticated is called.
	2	Expected IsAuthenticated to write the correct logs to the Logger. Two calls are expected.
	3	Verified that all expected methods where called (this acts the same as regular mock objects).

The First Mock

Example - Simple Mocking