Last Updated: 06 Nov 2013 10:30 by Ovidiu

Since I upgraded my JustMock I was unable to debug ASP.NET projects. I accidentally found a resolution to the problem here:

"If you are using Telerik JustMock as a mocking framework and have recently updated it to the 2013 Q3 version, it causes this exact problem. I was able to resolve this issue by uninstalling the mocking framework and installing the 2013 Q2 version."

So I uninstalled JustMock and everything came to normal.

Last Updated: 16 Jan 2019 08:51 by ADMIN
Created by: Michael
Comments: 4
Type: Bug Report
Creating a share link with Visual Studio Live Share does not work if you have the JustMock profiler enabled. We specifically have to disable the JustMock profiler in order for VS Live Share to create sharing links. This has been reproduced by several different members of our team.

Could this please be looked into? Thanks!
Last Updated: 05 Dec 2019 15:24 by ADMIN
The debugger arrowhead pointer is not positioned to the correct execution line when debugging .Net Core. Stepping the code line by line advances the yellow arrowhead pointer based on the initial offset/messed position. When the arrowhead leaves the method the remaining lines are executed at once.
Last Updated: 23 Jul 2018 12:48 by Stefan
My team and I have spotted some odd behaviour with the latest version of JustMock (2015.3.929.5) when targeting a Windows Store app.

If we create a mock for an object in a helper method, the mock fails when making assertions for calls to the mock.

The following code illustrates the issue:

        public void ThisWillFail()
            var subject = CreateSubject();


            subject.Assert(s => s.DoSomething(), Occurs.Once());

        public void ThisWillPass()
            var subject = Mock.Create<ISubject>();


            subject.Assert(s => s.DoSomething(), Occurs.Once());

        public interface ISubject
            void DoSomething();

        private static ISubject CreateSubject()
            return Mock.Create<ISubject>();

In this code, the first test will fail but the second test will pass. The only difference is that, in the first test, we're setting up the mock in a helper method.

We have a "Unit Test Library (.NET for Windows Store apps)" referencing the Telerik.JustMock assembly. I have attached a simple project containing this implementation.

It's worth noting that the same code passes in a regular .NET class library; it only fails in a "Unit Test Library (.NET for Windows Store apps)". It's also worth noting that this worked under an older version of the assembly (2014.3.1021.2).

Any help would be appreciated, as we currently have around 3,000 tests and a good proportion of them set up their mocks using a helper method in this way.

William Cowell
Last Updated: 18 Jun 2019 08:43 by ADMIN
There is a different behaviour when mocking the same method using the following two Arrange overrides:

public static FuncExpectation<TResult> Arrange<TResult>(Expression<Func<TResult>> expression);
public static FuncExpectation<TResult> Arrange<T, TResult>(T obj, Func<T, TResult> func);

Repro project attached. Steps to reproduce:
1. Open attached solution
2. In Tests.cs, run JustMockArrangeQueryableTest - it passes
3. Run JustMockArrangeQueryableTest2 - it fails with a invalid cast exception on the Residents collection.
Last Updated: 18 Jun 2019 08:37 by ADMIN
The integration between JustMock and dotCover stopped working with R2 2019. The result when code coverage is started is that all tests remain in pending state and does not finish while the CPU is idle.
Last Updated: 20 May 2019 09:32 by ADMIN
Mocking an async calls alse triggers hidden mocking of the return type. Depending of the type it might cause unexpected behavior or exception.
Last Updated: 20 May 2019 09:26 by ADMIN
A class property get wrongly mocked when used as parameter for arranging other class methods. The following sample demonstrates the scenario:

class Foo
	public string Prop{ get; set; }

	public void Bar(string val)

public void Sample()
	var sut = Mock.Create<Foo>(Behavior.CallOriginal);

	Mock.Arrange(() => sut.Bar(sut.Prop)).DoNothing();
Last Updated: 15 Jan 2020 09:58 by ADMIN
The JustMock tests are failing when the "Test platform version" option in the JustMock VSTest v.2 task is set to value "Installed by Tools Installer".
Last Updated: 05 Dec 2019 15:32 by ADMIN

Visual Studio debugger arrowhead pointer is messed when profiler is enabled with .Net Core 2.1, in VS2107/2019


  • Use elevated features like static mocking using JustMock
  • Enable profiler from VS JustMock extension
  • Run the test in debug mode

Code Snippet

Mock.SetupStatic(typeof(ElasticOperationsHelper), Behavior.Strict, StaticConstructor.Mocked);

Mock.Arrange(() => elasticRepository.IndexDocumentInElastic<IndexDocText>(Arg.IsAny<IndexDocText>(), Arg.IsAny<string>(), null)).Returns(response);


While debugging it's found the arrowhead pointer of VS debugger is messed up and pointing to wrong line numbers. It's quite difficult to develop unit tests at this situation. Is there any resolution of this problem.

I found an article in the support page has been declined due to same problem. Is this totally dependent on "CLR" fix and .Net profiler. If so could you please provide me the Bug details of Microsoft for the same?

I would also like to know why it's necessary to have profiler enabled for scenarios like "Static Mocking", "Non virtual method mocking", "Private Mocking" etc. 

Is this only happening for .Net core? 

Hyland Software is evaluating this product as their Mocking framework for unit testing of all .net core projects.

If there is no solution, how can any prospective customer consider this as a good fit for their usage? If there is any workaround possible at this moment?

Last Updated: 24 Sep 2019 10:06 by ADMIN
The execution of JustMock tests stoped working in Visual Studio. The exact version is 16.2.1. The error message is: "The profiler must be enabled to mock, arrange or execute the specified target."
Last Updated: 04 Nov 2013 16:02 by ADMIN
using NUnit.Framework;
using Telerik.JustMock;

namespace Example
    public class MyClass
        public MyClass(int a = 5) { }

    public class TestMyClass
        public void test_MyClass()

Telerik.JustMock.MockException : Can not instantiate proxy of class: Example.MyClass.
Could not find a parameterless constructor.
   at Telerik.JustMock.Core.MocksRepository.Create(Type type, MockCreationSettings settings)
   at Telerik.JustMock.MockBuilder.Create(MocksRepository repository, Type type, Object[] constructorArgs, Nullable`1 behavior, Type[] additionalMockedInterfaces, Nullable`1 mockConstructorCall, IEnumerable`1 additionalProxyTypeAttributes, List`1 supplementaryBehaviors, List`1 fallbackBehaviors, List`1 mixins)
   at Telerik.JustMock.Mock.<>c__DisplayClass5b`1.<Create>b__5a()
   at Telerik.JustMock.Core.ProfilerInterceptor.GuardInternal[T](Func`1 guardedAction)
   at Telerik.JustMock.Mock.Create[T](Behavior behavior, Object[] args)
   at Example.TestMyClass.test_MyClass() in c:\users\micah\Documents\Source\Test\Test\Class1.cs:line 17#0

This appears to be related to the recent fix for "Improve exception message for Mock.Create".  Without Behavior.CallOriginal it works.  Supplying a parameter also works.
Last Updated: 29 Nov 2017 12:53 by ADMIN
Tests fail when run with vstest.console.exe but pass when run from VS2015.

Findings: The problematic scenario includes reference to Microsoft.WindowsAzure.ServiceRuntime.dll and usage of the RoleEnvironment class. When the RoleEnvironment class is used in a test project without JustMock and runned from vstest.console the exception will be thrown as well. Here is the exact exception: 
System.TypeInitializationException: The type initializer for 'Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironment' threw an exception. ---> System.TypeInitializationException: The type initializer for '<Module>' threw an exception. ---> <CrtImplementationDetails>.ModuleLoadException: The C++ module failed to load while attempting to initialize the default appdomain.
 ---> System.Runtime.InteropServices.COMException: Invalid operation. (Exception from HRESULT: 0x80131022)
Stack Trace:
    at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at <CrtImplementationDetails>.GetDefaultDomain()
   at <CrtImplementationDetails>.DoCallBackInDefaultDomain(IntPtr function, Void* cookie)
   at <CrtImplementationDetails>.LanguageSupport.InitializeDefaultAppDomain(LanguageSupport* )
   at <CrtImplementationDetails>.LanguageSupport._Initialize(LanguageSupport* )
   at <CrtImplementationDetails>.LanguageSupport.Initialize(LanguageSupport* )
--- End of inner exception stack trace ---
    at <CrtImplementationDetails>.LanguageSupport.Initialize(LanguageSupport* )
   at .cctor()
--- End of inner exception stack trace ---
    at Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironment.InitializeEnvironment()
   at Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironment..cctor()
--- End of inner exception stack trace ---
    at Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironment.get_IsAvailable()

Workaround: the vstest.console.exe could be started with parameter /InIsolation, which runs the tests in an isolated process. Here is the link to the command line options:
Last Updated: 17 May 2013 12:29 by Mohd
Created by: Mihail
Comments: 1
Type: Bug Report
Since JustMock Q1 2013 Mock.DoNotUseProfiler() is marked as an obsolete method and I cannot compile my test project. Revert it back.
Last Updated: 17 May 2013 12:23 by David
I'm getting this argument exception:
System.ArgumentException : The type or method has 3 generic parameter(s), but 2 generic argument(s) were provided. A generic argument must be provided for each generic parameter.
   at System.RuntimeType.SanityCheckGenericArguments(RuntimeType[] genericArguments, RuntimeType[] genericParamters)
   at System.Reflection.RuntimeMethodInfo.MakeGenericMethod(Type[] methodInstantiation)
   at .š.(Type ‹, MethodBase „†, BindingFlags )
   at .š.(Type ‚, MethodBase „†)
   at ”.“.Create(Object š, MethodInfo ›, Boolean ’)
   at ..(˜ )
   at ..(Expression`1 )
   at Telerik.JustMock.Mock..Ž( )
   at ..—[,—]( , Func`2 )
   at Telerik.JustMock.Mock.Arrange[TResult](Expression`1 expression)

Heres an example of a failing test:

        public void GenericTestCanMockTwoGenericMethods()
            var mocked = Mock.Create<GenericTest>();
            IEnumerable<EVENT_CODE> n = null;
            Mock.Arrange(() => mocked.Query<EVENT_CODE, ALARM_CODE>(Arg.AnyString, Arg.IsAny<object>())).Returns(n).MustBeCalled();

        public interface GenericTest
            IEnumerable<T1> Query<T1, T2>(string arg1, params object[] args);

            IEnumerable<T1> Query<T1, T2, T3>(string arg1, params object[] args);
Last Updated: 22 Nov 2012 15:00 by Philip Japikse
If I have a constructor like this: public Foo(IAccount fromAccount, IAccount toAccount) { //code }, I need to be able to distinguish between the two accounts when automocking.
container.Arrange<IAccount>() won't work.  Perhaps container.Arrange<IAccount>[0] would. 
Pending Review
Last Updated: 19 Apr 2017 08:19 by Maxim
Created by: Maxim
Comments: 0
Type: Bug Report
I have logging class which are using everywhere.
I want to Mock this class for all tests. And i tried to use AssemblyInitialize but got problem. I have simulated this problem with JustMock.ElevatedExamples.AdvancedUsage examples:
1) Add BaseTest class
    public class BaseTest
        public static void AssemblyInit(TestContext context)
            Mock.SetupStatic(typeof(Common1), StaticConstructor.Mocked);
            // Arranging: When the static(Foo.FooProp_GET) property is called, it should return expected.
            var fakeUsed = Mock.Create<LogWriter1>(Constructor.Mocked);
            Mock.Arrange(() => Common1.Log).Returns(fakeUsed);

        public static void Cleanup()
            //clean up stuff here
    public static class Common1
        static Common1()

            Log = new LogWriter1();


        public static LogWriter1 Log { get; set; }


    public class LogWriter1


2) When run test from VS - all ok
3) When run from command line it is not working. Show Message box "Process Starts Now".

SET COR_PROFILER={B7ABE522-A68F-44F2-925B-81E7488E9EC0}
"C:\Program Files (x86)\Telerik\JustMock\Libraries\JustMockRunner.exe" "C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\MSTest.exe" /testcontainer:"D:\test\CSExamples\JustMock.ElevatedExamples\bin\Debug\JustMock.ElevatedExamples.dll"

How i can mock logger for all test? It is static public property.

I use MS Test + VS 2015.
Last Updated: 24 Nov 2015 08:37 by Simo
I have installed the trial version of JustMock to evaluate it. I have been trying to mock the static calls of Azure RoleEnvironment class, but the SetupStatic does not work. It seems to be calling the original method. Please see my simple test below:

public void VerifyRoleEnvironment()
       bool expected = true;
       Mock.SetupStatic(typeof(RoleEnvironment), StaticConstructor.Mocked);
       Mock.Arrange(() => RoleEnvironment.IsAvailable).Returns(true);
       Assert.AreEqual(expected, RoleEnvironment.IsAvailable);
Last Updated: 10 Jan 2014 09:04 by ADMIN
1. Load the attached project in Visual Studio 2013.
2. Update the NuGet packages (NUnit).
3. Update the reference to JustMock to point to the correct path to a retail version of Telerik.JustMock.dll.
4. Run tests in NUnit runner (or any other runner that will run them in the same process/sequentially.
5. --> Notice that the first TestCase will pass, the second will fail.
6. Run the two test cases separately.
7. --> Notice that they both pass.
8. Remove the reference to Telerik.JustMock.dll.
9. Use NuGet to get the latest JustMock Lite.
10. Run the tests again.
11. --> Notice that they both pass.

This appears to be a bug with JustMock (retail) 2013.3.1119.2.  The bug does not reproduce when using JustMock Lite from NuGet.

If you drop into a debugger and step through both tests in a row you see the following behavior:
1. When the first test is started (after SetUp has been called) FlagA is correctly set to true and FlagB is defaulted to false.
2. When you step over the Mock.Arrange, FlagA is still true and FlagB is set to the value of input (order of running tests doesn't appear to matter, second always fails).
3. When the second test starts (after SetUp has been called again) Flag A is correctly set to true and FlagB is defaulted to false.
4. When you step over the Mock.Arrange, FlagB is set to the value of input but FlagA has been reverted to default!

If you add several other properties to the interface they will all be reset to default (no matter how many you arrange) when the second test executes the Mock.Arrange.

This bug reproduces without the JustMock profiler attached, and also with the profiler attached.

The version of JustMock Lite that was tested against is 2014.1.1217.4.  When I run the Telerik Control Panel I am not prompted to update my version of JustMock beyond 2013.3.1119.2 (perhaps this bug is already fixed and I just need to figure out how to upgrade).
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