Mocking Non-public Members and Types

In elevated mode, you can use TelerikĀ® JustMock to mock non-public members and types. That is useful when you want to isolate calls to non-public members.

This feature is available only in the commercial version of Telerik JustMock. Refer to this topic to learn more about the differences between the commercial and free versions.

In the further examples we will use the following sample class to test:

public class Foo 
{ 
    private void DoPrivate() 
    { 
        throw new NotImplementedException(); 
    } 
 
    private void DoPrivate(int arg) 
    { 
        throw new NotImplementedException(); 
    } 
 
    public void DoPublic() 
    { 
        DoPrivate(); 
    } 
 
    private void DoPrivateGeneric<T>(T arg) 
    { 
        throw new NotImplementedException(); 
    } 
 
    public void DoPublicGeneric<T>(T arg) 
    { 
        DoPrivateGeneric<T>(arg); 
    } 
 
    public void Execute(int arg) 
    { 
        DoPrivate(arg); 
    } 
 
    private int PrivateEcho(int arg) 
    { 
        return arg; 
    } 
 
    public int Echo(int arg) 
    { 
        return PrivateEcho(arg); 
    } 
 
    internal virtual void Do() 
    { 
        throw new NotImplementedException(); 
    } 
 
    internal virtual string Value 
    { 
        get 
        { 
            throw new NotImplementedException(); 
        } 
        set 
        { 
            throw new NotImplementedException(); 
        } 
    } 
 
    private static int PrivateStaticProperty { get; set; } 
 
    public int GetMyPrivateStaticProperty() 
    { 
        return PrivateStaticProperty; 
    } 
} 
Public Class Foo 
    Private Sub DoPrivate() 
        Throw New NotImplementedException() 
    End Sub 
 
    Private Sub DoPrivate(arg As Integer) 
        Throw New NotImplementedException() 
    End Sub 
 
    Public Sub DoPublic() 
        DoPrivate() 
    End Sub 
 
    Private Sub DoPrivateGeneric(Of T)(ByVal arg As T) 
        Throw New NotImplementedException() 
    End Sub 
 
    Public Sub DoPublicGeneric(Of T)(ByVal arg As T) 
        DoPrivateGeneric(Of T)(arg) 
    End Sub 
 
    Public Sub Execute(arg As Integer) 
        DoPrivate(arg) 
    End Sub 
 
    Private Function PrivateEcho(arg As Integer) As Integer 
        Return arg 
    End Function 
 
    Public Function Echo(arg As Integer) As Integer 
        Return PrivateEcho(arg) 
    End Function 
 
    Friend Overridable Sub Do 
        Throw New NotImplementedException() 
    End Sub 
 
    Friend Overridable Property Value() As String 
        Get 
            Throw New NotImplementedException() 
        End Get 
        Set(value As String) 
            Throw New NotImplementedException() 
        End Set 
    End Property 
 
    Private Shared Property PrivateStaticProperty() As Integer 
        Get 
            Return m_PrivateStaticProperty 
        End Get 
        Set(value As Integer) 
            m_PrivateStaticProperty = Value 
        End Set 
    End Property 
    Private Shared m_PrivateStaticProperty As Integer 
 
    Public Function GetMyPrivateStaticProperty() As Integer 
        Return PrivateStaticProperty 
    End Function 
End Class 

Important

To mock non-public members and types you first need to go to elevated mode by enabling TelerikJustMock from the menu. How to Enable/Disable

Step by step example

First, create an instance of the type you want to test. To mock a non-public member use the Mock.NonPublic modifier and then add the arrange statement. In the arrange statement, first pass the target object to test, then the member name that you want to test as a string and eventually the arguments to be passed in case you test a method.

[TestMethod] 
public void ShouldInvokeNonPublicMember() 
{ 
    Foo foo = new Foo(); 
 
    bool called = false; 
 
    // Arrange 
    Mock.NonPublic.Arrange(foo, "DoPrivate").DoInstead(() => called = true); 
 
    // Act 
    foo.DoPublic(); 
 
    // Assert 
    Assert.IsTrue(called); 
} 
<TestMethod> 
Public Sub ShouldInvokeNonPublicMember() 
    Dim foo As New Foo() 
 
    Dim called As Boolean = False 
 
    ' Arrange 
    Mock.NonPublic.Arrange(foo, "DoPrivate").DoInstead(Sub() called = True) 
 
    ' Act 
    foo.DoPublic() 
 
    ' Assert 
    Assert.IsTrue(called) 
End Sub 

Here we setup that a call to the DoPrivate method of the Foo class should set a local variable called. Thus, we override the original method behavior with one that we specify.

Mock.NonPublic can be also used to mock generic non-public methods. In addition to the non-generic method mock the generic type arguments has to be supplied in the arrangement, the code look as following:

[TestMethod] 
public void ShouldInvokeNonPublicGenericMember() 
{ 
    Foo foo = new Foo(); 
 
    bool called = false; 
 
    // Arrange 
    Mock.NonPublic.Arrange(foo, "DoPrivateGeneric", new Type[] { typeof(int) }, 10).DoInstead(() => called = true); 
 
    // Act 
    foo.DoPublicGeneric<int>(10); 
 
    // Assert 
    Assert.IsTrue(called); 
} 
<TestMethod> 
Public Sub ShouldInvokeNonPublicGenericMember() 
    Dim foo As Foo = New Foo() 
 
    Dim called As Boolean = False 
 
    ' Arrange 
    Mock.NonPublic.Arrange(foo, "DoPrivateGeneric", New Type() {GetType(Integer)}, 10).DoInstead(Sub() called = True) 
 
    ' Act 
    foo.DoPublicGeneric(Of Integer)(10) 
 
    ' Assert 
    Assert.IsTrue(called) 
End Sub 

Mock Private Call with Matcher

Arrange a call to a private method accepting an argument that matches any integer value.

[TestMethod] 
public void ShouldInvokeNonPublicMemberWithMatcher() 
{ 
    Foo foo = new Foo(); 
 
    int expected = 1; 
 
    // Arrange 
    Mock.NonPublic.Arrange<int>(foo, "PrivateEcho", ArgExpr.IsAny<int>()).Returns(expected); 
 
    // Act 
    int actual = foo.Echo(5); 
 
    // Assert 
    Assert.AreEqual(expected, actual); 
} 
<TestMethod> 
Public Sub ShouldInvokeNonPublicMemberWithMatcher() 
    Dim foo As New Foo() 
 
    Dim expected As Integer = 1 
 
    ' Arrange 
    Mock.NonPublic.Arrange(Of Integer)(foo, "PrivateEcho", ArgExpr.IsAny(Of Integer)()).Returns(expected) 
 
    ' Act 
    Dim actual As Integer = foo.Echo(5) 
 
    ' Assert 
    Assert.AreEqual(expected, actual) 
End Sub 

Here we specify that PrivateEcho method called with any int argument will return 1. Acting is by calling it with 5 as argument. Finally, we verify that the return value is actually 1.

Natural Mocking Using a Dynamic Wrapper

JustMock leverages .NET 4 and the DLR to allow you to arrange non-public members as naturally as you can public members.

In the example below, we wrap the mock instance in a dynamic object using Mock.NonPublic.Wrap(). The wrapper can be passed to Mock.NonPublic.Arrange and Mock.NonPublic.Assert together with an operation to specify what you want to arrange. We could also arrange the value of a property getter or the action of a property setter. Matchers are again passed using members of the ArgExpr class.

You need to reference the Microsoft.CSharp assembly when using dynamic expressions in Visual C# projects.

[TestMethod] 
public void ShouldInvokeNonPublicMemberDynamic() 
{ 
    Foo foo = new Foo(); 
 
    // Arrange 
    dynamic fooAcc = Mock.NonPublic.Wrap(foo); 
    Mock.NonPublic.Arrange<int>(fooAcc.PrivateEcho(ArgExpr.IsAny<int>())).Returns(10); 
    Mock.NonPublic.Arrange<string>(fooAcc.Value).Returns("foo"); 
    Mock.NonPublic.Arrange(fooAcc.Value = "abc").OccursOnce(); 
 
    // Act 
    var actual = foo.Echo(5); 
    var value = foo.Value; 
    foo.Value = "abc"; 
 
    // Assert 
    Assert.AreEqual(10, actual); 
    Assert.AreEqual("foo", value); 
    Mock.Assert(foo); 
} 
<TestMethod> 
Public Sub ShouldInvokeNonPublicMemberDynamic() 
    Dim foo As New Foo() 
 
    ' Arrange 
    Dim fooAcc As Object = Mock.NonPublic.Wrap(foo) 
    Mock.NonPublic.Arrange(Of Integer)(fooAcc.PrivateEcho(ArgExpr.IsAny(Of Integer)())).Returns(10) 
    Mock.NonPublic.Arrange(Of String)(fooAcc.Value).Returns("foo") 
    Mock.NonPublic.Arrange(fooAcc.Value = "abc").OccursOnce() 
 
    ' Act 
    Dim actual As Integer = foo.Echo(5) 
    Dim value As String = foo.Value 
    foo.Value = "abc" 
 
    ' Assert 
    Assert.AreEqual(10, actual) 
    Assert.AreEqual("foo", value) 
    Mock.Assert(foo) 
End Sub 

Mock Private Method with Overloads

Here we arrange a call to a private method with two overloads. The following class will be used:

internal class FooInternal 
{ 
    private void pExecute(int arg1) 
    { 
        throw new NotImplementedException(); 
    } 
 
    private void pExecute() 
    { 
        throw new NotImplementedException(); 
    } 
 
    public void Execute(int arg1) 
    { 
        pExecute(arg1); 
    } 
 
    public void Execute() 
    { 
        pExecute(); 
    } 
} 
Friend Class FooInternal 
Private Sub pExecute(arg1 As Integer) 
    Throw New NotImplementedException() 
End Sub 
 
Private Sub pExecute() 
    Throw New NotImplementedException() 
End Sub 
 
Public Sub Execute(arg1 As Integer) 
    pExecute(arg1) 
End Sub 
 
Public Sub Execute() 
    pExecute() 
End Sub 

End Class

Important

To interact with non-public classes you will need to add the InternalVisibleTo property inside the AssemblyInfo.cs in your project, like this:

[assembly: InternalsVisibleTo("YourTestProject")] 

We mock the pExecute method that accepts an integer value as argument. We arrange it to set a local boolean variable to true once it is called with 10 as argument. After that we act by calling foo.Execute(10) and verify that called is true.

[TestMethod] 
public void ShouldInvokeNonPublicMemberWithOverloads() 
{ 
    FooInternal foo = new FooInternal(); 
    bool isCalled = false; 
 
    // Arrange 
    Mock.NonPublic.Arrange(foo, "pExecute", 10).DoInstead(() => isCalled = true); 
 
    // Act 
    foo.Execute(10); 
 
    // Assert 
    Assert.IsTrue(isCalled); 
} 
<TestMethod> _ 
Public Sub ShouldInvokeNonPublicMemberWithOverloads() 
    ' Arrange 
    Dim foo As New FooInternal() 
    Dim isCalled As Boolean = False 
 
    ' Arrange 
    Mock.NonPublic.Arrange(foo, "pExecute", 10).DoInstead(Sub() isCalled = True) 
 
    ' Act 
    foo.Execute(10) 
 
    ' Assert 
    Assert.IsTrue(isCalled) 
End Sub 

Mock Private Interface Implementation Method

This example shows how we can mock an explicit (not public) interface implementation method from current or base class.

The following classes will be used:

public interface IManager 
{ 
    object Provider { get; } 
} 
 
public class FooBase : IManager 
{ 
    object IManager.Provider 
    { 
        get { throw new NotImplementedException(); } 
    } 
} 
 
public class Bar : FooBase 
{ 
    //... 
} 
Public Interface IManager 
    ReadOnly Property Provider() As Object 
End Interface 
 
Public Class FooBase 
    Implements IManager 
    Private ReadOnly Property Provider() As Object Implements IManager.Provider 
        Get 
            Throw New NotImplementedException() 
        End Get 
    End Property 
End Class 
 
Public Class Bar 
    Inherits FooBase 
    '... 
End Class 

We can now mock the IManager.Provider call in this way:

[TestMethod] 
public void ShouldMockPrivateInterfaceImplementationMethod() 
{ 
    const string expected = "dummy"; 
 
    // Arrange 
    var bar = Mock.Create<Bar>(); 
    Mock.Arrange(() => ((IManager)bar).Provider).Returns(expected); 
 
    // Act, Assert 
    Assert.AreEqual(expected, ((IManager)bar).Provider); 
} 
<TestMethod> _ 
Public Sub ShouldMockPrivateInterfaceImplementationMethod() 
    Const expected As String = "dummy" 
 
    ' Arrange 
    Dim bar = Mock.Create(Of Bar)() 
    Mock.Arrange(Function() DirectCast(bar, IManager).Provider).Returns("dummy") 
 
    ' Act, Assert 
    Assert.AreEqual(expected, DirectCast(bar, IManager).Provider) 
End Sub 

Mock Internal Virtual Method

Arrange a call to an internal virtual method.

[TestMethod] 
public void ShouldMockInternalVirtualMethod() 
{ 
    Foo foo = new Foo(); 
 
    bool isCalled = false; 
 
    // Arrange 
    Mock.Arrange(() => foo.Do()).DoInstead(() => isCalled = true); 
 
    // Act 
    foo.Do(); 
 
    // Assert 
    Assert.IsTrue(isCalled); 
} 
<TestMethod> _ 
Public Sub ShouldMockInternalVirtualMethod() 
    Dim foo As New Foo() 
 
    Dim isCalled As Boolean = False 
 
    ' Arrange 
    Mock.Arrange(Sub() foo.Do()).DoInstead(Sub() isCalled = True) 
 
    ' Act 
    foo.Do 
 
    ' Assert 
    Assert.IsTrue(isCalled) 
End Sub 

Note that in the arrange statement we don't use a mock of Foo, but the actual instance.

Mock Internal Virtual Property Get And Set

Arrange a call to an internal virtual property.

[TestMethod] 
public void ShouldMockInternalVirtualPropertyGET() 
{ 
    Foo foo = new Foo(); 
 
    // Arrange 
    Mock.Arrange(() => foo.Value).Returns("ping"); 
 
    // Act 
    string actual = foo.Value; 
 
    // Assert 
    Assert.AreEqual("ping", actual); 
} 
<TestMethod> _ 
Public Sub ShouldMockInternalVirtualPropertyGET() 
    Dim foo As New Foo() 
 
    ' Arrange 
    Mock.Arrange(Function() foo.Value).Returns("ping") 
 
    ' Act 
    Dim actual As String = foo.Value 
 
    ' Assert 
    Assert.AreEqual("ping", actual) 
End Sub 

Note that in the arrange statement we don't use a mock of Foo, but the actual instance.

Follows an example of mocking internal virtual property set. We override the actual implementation by arranging that the foo.Value must be called with certain value.

[TestMethod] 
public void ShouldMockInternalVirtualPropertySET() 
{ 
    // Arrange 
    Foo foo = Mock.Create<Foo>(); 
    Mock.ArrangeSet(() => foo.Value = "ping").MustBeCalled(); 
 
    // Act 
    foo.Value = "ping"; 
 
    // Assert 
    Mock.Assert(foo); 
} 
<TestMethod> _ 
Public Sub ShouldMockInternalVirtualPropertySET() 
    ' Arrange 
    Dim foo As Foo = Mock.Create(Of Foo)() 
    Mock.ArrangeSet(Sub() foo.Value = "ping").MustBeCalled() 
 
    ' Act 
    foo.Value = "ping" 
 
    ' Assert 
    Mock.Assert(foo) 
End Sub 

Mock Private Static Method

The following example shows how to mock a private static method. We use the following class:

internal class FooInternalStatic 
{ 
    private static int EchoPrivate(int arg1) 
    { 
        throw new NotImplementedException(); 
    } 
 
    public static int Echo(int arg1) 
    { 
        return EchoPrivate(arg1); 
    } 
 
    private static int EchoPrivateGeneric<T>(T arg1) 
    { 
        throw new NotImplementedException(); 
    } 
 
    public static int EchoGeneric<T>(T arg1) 
    { 
        return EchoPrivateGeneric<T>(arg1); 
    } 
} 
Friend Class FooInternalStatic 
    Private Shared Function EchoPrivate(arg1 As Integer) As Integer 
        Throw New NotImplementedException() 
    End Function 
 
    Public Shared Function Echo(arg1 As Integer) As Integer 
        Return EchoPrivate(arg1) 
    End Function 
 
    Private Shared Function EchoPrivateGeneric(Of T)(ByVal arg1 As T) As Integer 
        Throw New NotImplementedException() 
    End Function 
 
    Public Shared Function EchoGeneric(Of T)(ByVal arg1 As T) As Integer 
        Return EchoPrivateGeneric(Of T)(arg1) 
    End Function 
End Class 

Important

To interact with non-public classes you will need to add the InternalVisibleTo property inside the AssemblyInfo.cs in your project, like this:

[assembly: InternalsVisibleTo("YourTestProject")] 

The method we arrange is FooInternalStatic.EchoPrivate().

[TestMethod] 
public void ShouldMockPrivateStaticMethod() 
{ 
    // Arrange 
    Mock.NonPublic.Arrange<FooInternalStatic, int>("EchoPrivate", 10); 
 
    // Act 
    FooInternalStatic.Echo(10); 
 
    // Assert 
    Mock.NonPublic.Assert<FooInternalStatic, int>("EchoPrivate", 10); 
} 
<TestMethod> _ 
Public Sub ShouldMockPrivateStaticMethod() 
    ' Arrange 
    Mock.NonPublic.Arrange(Of FooInternalStatic, Integer)("EchoPrivate", 10) 
 
    ' Act 
    FooInternalStatic.Echo(10) 
 
    ' Assert 
    Mock.NonPublic.Assert(Of FooInternalStatic, Integer)("EchoPrivate", 10) 
End Sub 

We call the Echo method, but its implementation calls the EchoPrivate method, so our assertion passes.

Like a non-public instance generic methods Mock.NonPublic can be used to mock non-public static generic ones, here is the sample test:

[TestMethod] 
public void ShouldMockPrivateStaticGenericMethod() 
{ 
    // Arrange 
    Mock.NonPublic.Arrange<FooInternalStatic, int>("EchoPrivateGeneric", new Type[] { typeof(int) }, 10); 
 
    // Act 
    FooInternalStatic.EchoGeneric<int>(10); 
 
    // Assert 
    Mock.NonPublic.Assert<FooInternalStatic, int>("EchoPrivateGeneric", new Type[] { typeof(int) }, 10); 
} 
<TestMethod> 
Public Sub ShouldMockPrivateStaticGenericMethod() 
    ' Arrange 
    Mock.NonPublic.Arrange(Of FooInternalStatic, Integer)("EchoPrivateGeneric", New Type() {GetType(Integer)}, 10) 
 
    ' Act 
    FooInternalStatic.EchoGeneric(Of Integer)(10) 
 
    ' Assert 
    Mock.NonPublic.Assert(Of FooInternalStatic, Integer)("EchoPrivateGeneric", New Type() {GetType(Integer)}, 10) 
End Sub 

Mock Private Static Property

The following example shows how to mock the get function of a private static property. We use the Foo class from above.

The property we arrange is Foo.PrivateStaticProperty. When called, it will return an expected integer value, different from the default:

[TestMethod] 
public void ShouldMockPrivateStaticProperty() 
{ 
    var expected = 10; 
 
    // Arrange 
    Foo foo = new Foo(); 
 
    Mock.NonPublic.Arrange<int>(typeof(Foo), "PrivateStaticProperty").Returns(expected); 
 
    // Act 
    int actual = foo.GetMyPrivateStaticProperty(); 
 
    // Assert 
    Assert.AreEqual(expected, actual); 
} 
<TestMethod> _ 
Public Sub ShouldMockPrivateStaticProperty() 
    Dim expected = 10 
 
    ' Arrange 
    Dim foo As New Foo() 
 
    Mock.NonPublic.Arrange(Of Integer)(GetType(Foo), "PrivateStaticProperty").Returns(expected) 
 
    ' Act 
    Dim actual As Integer = foo.GetMyPrivateStaticProperty() 
 
    ' Assert 
    Assert.AreEqual(expected, actual) 
End Sub 

To act, we call the GetMyPrivateStaticProperty() method, but its implementation returns the PrivateStaticProperty, so our assertion passes.

Mock Internal Class

Let's see an example of how to mock an internal class from .NET framework. Consider the System.Net.HttpRequestCreator class which is internal, but has a public interface System.Net.IWebRequestCreate. Here we mock its Create method.

[TestMethod] 
public void ShouldMockInternaldotNETClass() 
{ 
    // Arrange 
    string typeName = "System.Net.HttpRequestCreator"; 
 
    var httpRequestCreator = Mock.Create(typeName); 
 
    bool isCalled = false; 
 
    Mock.NonPublic.Arrange(httpRequestCreator, "Create", ArgExpr.IsAny<Uri>()).DoInstead(() => isCalled = true); 
 
    // Act 
    System.Net.IWebRequestCreate iWebRequestCreate = (System.Net.IWebRequestCreate)httpRequestCreator; 
 
    iWebRequestCreate.Create(new Uri("https://www.telerik.com")); 
 
    // Assert 
    Assert.IsTrue(isCalled); 
} 
<TestMethod> _ 
Public Sub ShouldMockInternaldotNETClass() 
    ' Arrange 
    Dim typeName As String = "System.Net.HttpRequestCreator" 
 
    Dim httpRequestCreator = Mock.Create(typeName) 
 
    Dim isCalled As Boolean = False 
 
    Mock.NonPublic.Arrange(httpRequestCreator, "Create", ArgExpr.IsAny(Of Uri)()).DoInstead(Sub() isCalled = True) 
 
    ' Act 
    Dim iWebRequestCreate As System.Net.IWebRequestCreate = DirectCast(httpRequestCreator, System.Net.IWebRequestCreate) 
 
    iWebRequestCreate.Create(New Uri("https://www.telerik.com")) 
 
    ' Assert 
    Assert.IsTrue(isCalled) 
End Sub 

Note the use of ArgExpr.IsAny<Uri>() - as we mock a non-public call, we need to know the type of the argument to resolve the method. Thus, instead of using Arg, like we do in most of the other cases, we must use ArgExpr.

Important

To mock internal type, your assembly name must be fully qualified according to the framework design rules, i.e. assembly name = namespace. Note that you can't mock types from mscorlib in this way. We do a hierarchical search to find the proper qualified name as in the above example. System.Net.HttpRequestCreator is found in the System assembly, not in System.Net.

With the next sample we can handle even more complex scenario - mock internal class by calling original constructor with arguments, then make a call to the original implementation from public interface. This time we will use another internal class System.Net.WebSocketHttpRequestCreator derived from public interface System.Net.IWebRequestCreate

[TestMethod] 
public void ShouldMockInternaldotNETClassWithArgs() 
{ 
    // Arrange 
    string typeName = "System.Net.WebSocketHttpRequestCreator"; 
 
    var httpRequestCreator = Mock.Create(typeName, (config) => config 
        .CallConstructor(new object[] {true})); 
 
    Mock.NonPublic.Arrange(httpRequestCreator, "Create", ArgExpr.IsAny<Uri>()) 
        .CallOriginal() 
        .MustBeCalled(); 
 
    // Act 
    System.Net.IWebRequestCreate iWebRequestCreate = (System.Net.IWebRequestCreate)httpRequestCreator; 
 
    var result = iWebRequestCreate.Create(new Uri("https://www.telerik.com")); 
 
    // Assert 
    Mock.Assert(httpRequestCreator); 
    Assert.AreEqual(new Uri("https://www.telerik.com"), result.RequestUri); 
} 
<TestMethod> 
Public Sub ShouldMockInternaldotNETClassWithArgs() 
    ' Arrange 
    Dim typeName As String = "System.Net.WebSocketHttpRequestCreator" 
 
    Dim httpRequestCreator = Mock.Create(typeName, Sub(config) _ 
        config.CallConstructor(New Object() {True})) 
 
    Mock.NonPublic.Arrange(httpRequestCreator, "Create", ArgExpr.IsAny(Of Uri)()) _ 
        .CallOriginal() _ 
        .MustBeCalled() 
 
    ' Act 
    Dim iWebRequestCreate As System.Net.IWebRequestCreate = DirectCast(httpRequestCreator, System.Net.IWebRequestCreate) 
 
    Dim result = iWebRequestCreate.Create(New Uri("https://www.telerik.com")) 
 
    ' Assert 
    Mock.Assert(httpRequestCreator) 
 
    Assert.AreEqual(New Uri("https://www.telerik.com"), result.RequestUri) 
End Sub 

The sample test verifies whether the call to Create method has been made and the returned Web.WebRequest object has an expected value for RequestUri property set.

Mock Protected Member

To show how the mocking of protected members is being done, we will use the following class:

public class FooWithProtectedMembers 
{ 
    protected virtual void Load() 
    { 
        throw new NotImplementedException(); 
    } 
 
    protected virtual int IntValue 
    { 
        get 
        { 
            throw new NotImplementedException(); 
        } 
    } 
 
    public virtual void Init() 
    { 
        Load(); 
    } 
} 
Public Class FooWithProtectedMembers 
Protected Overridable Sub Load() 
    Throw New NotImplementedException() 
End Sub 
 
Protected Overridable ReadOnly Property IntValue() As Integer 
    Get 
        Throw New NotImplementedException() 
    End Get 
End Property 
 
Public Overridable Sub Init() 
    Load() 
End Sub 

End Class

To mock protected members in JustMock, we use the same method and logic, as for the rest non-public types, shown above:

First we will arrange that our IntValue() method should never occur, like this:

[TestMethod] 
public void ShouldAssertOccrenceForNonPublicFunction() 
{ 
    var foo = Mock.Create<FooWithProtectedMembers>(Behavior.CallOriginal); 
 
    Mock.NonPublic.Assert<int>(foo, "IntValue", Occurs.Never()); 
} 
<TestMethod> _ 
Public Sub ShouldAssertOccrenceForNonPublicFunction() 
    Dim foo = Mock.Create(Of FooWithProtectedMembers)(Behavior.CallOriginal) 
 
    Mock.NonPublic.Assert(Of Integer)(foo, "IntValue", Occurs.Never()) 
End Sub 

The second test will test if our protected Load() method is actually been called, when Init() is initiated.

[TestMethod] 
public void ShouldMockProtectedVirtualMembers() 
{ 
    var foo = Mock.Create<FooWithProtectedMembers>(Behavior.CallOriginal); 
 
    Mock.NonPublic.Arrange(foo, "Load").MustBeCalled(); 
 
    foo.Init(); 
 
    Mock.Assert(foo); 
} 
<TestMethod> _ 
Public Sub ShouldMockProtectedVirtualMembers() 
    Dim foo = Mock.Create(Of FooWithProtectedMembers)(Behavior.CallOriginal) 
 
    Mock.NonPublic.Arrange(foo, "Load").MustBeCalled() 
 
    foo.Init() 
 
    Mock.Assert(foo) 
End Sub 

Important

To mock protected type, your assembly name must be fully qualified according to the framework design rules, i.e. assembly name = namespace. Note that you can't mock types from mscorlib in this way.

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