Unit-testing WCF: Server Side

Original Method

The following sample shows a method of the server which returns a string containing a list of our favorite sources.

C#

[ServiceContract(Namespace = "http://AnyServer")]
public interface ISourceListProvider
{
    [OperationContract]
    string GetSourceList(string source);

}

public class XMLProvider: ISourceListProvider
{
    public string GetSourceList(string source)
    {
        MessageHeaderInfo headerInfo = OperationContext.Current.IncomingMessageHeaders[0];
        if (headerInfo.Name != "ID")
        {
            throw new ArgumentException("Bad Header Info");
        }
        return "<SourceList><Source value=" + source + "/></SourceList>";
    }
}

VB
<ServiceContract([Namespace]:="http://AnyServer")>
Public Interface ISourceListProvider
    <OperationContract>
    Function GetSourceList(source As String) As String

End Interface

Public Class XMLProvider
    Implements ISourceListProvider
    Public Function GetSourceList(source As String) As String Implements ISourceListProvider.GetSourceList
        Dim headerInfo As MessageHeaderInfo = OperationContext.Current.IncomingMessageHeaders(0)
        If headerInfo.Name <> "ID" Then
            Throw New ArgumentException("Bad Header Info")
        End If
        Return (Convert.ToString("<SourceList><Source value=") & source) + "/></SourceList>"
    End Function
End Class

Typemock Isolator Features Used

• Faking Static Methods

• Faking an Instance

• Modifying methods and properties behavior

Scenario

1. Get a handle for a fake Instance of MessageHeaderInfo.

2. Modify the property MessageHeaderInfo.Name to return "ID".

3. Modify the static method OperationContext.Current.IncomingMessageHeaders[0] to return fakeInfo.

4. Create XMLProvider instance and call the method under test, GetSourceList ,and check if the result is as anticipated.

Code

C#
[TestMethod, Isolated]
public void GetData_SimulateGoodMessageHeader()
{
    // Arrange 
    // Faking MessageHeaderInfo becuase it's an abstarct class and we can't create an instance of it.     
    MessageHeaderInfo fakeInfo = Isolate.Fake.Instance<MessageHeaderInfo>();

    Isolate.WhenCalled(() => fakeInfo.Name).WillReturn("ID");
    Isolate.WhenCalled(() => OperationContext.Current.IncomingMessageHeaders[0]).WillReturn(fakeInfo);

    // Act
    XMLProvider provider = new XMLProvider();
    string result = provider.GetSourceList("MySource");

    // Assert
    Assert.AreEqual(@"<SourceList><Source value=MySource/></SourceList>", result);
}

VB
<TestMethod(), Isolated()>
Public Sub GetData_SimulateGoodMessageHeader()
    
    ' Arrange 
    ' Faking MessageHeaderInfo becuase it's an abstarct class and we can't create an instance of it.
    Dim fakeInfo As MessageHeaderInfo = Isolate.Fake.Instance(Of MessageHeaderInfo)()

    Isolate.WhenCalled(Function() fakeInfo.Name).WillReturn("ID")
    Isolate.WhenCalled(Function() OperationContext.Current.IncomingMessageHeaders(0)).WillReturn(fakeInfo)

    ' Act
    Dim provider As New XMLProvider()
    Dim result As String = provider.GetSourceList("MySource")

    ' Assert
    Assert.AreEqual("<SourceList><Source value=MySource/></SourceList>", result)
End Sub