Under Review
Last Updated: 15 Oct 2021 13:45 by ADMIN
Created by: Jason
Comments: 2
Type: Bug Report

I've already created an issue in the JustMock repo, you can find it here: https://github.com/telerik/JustMockLite/issues/162. Below is the text from that issue...

I'm currently working on a PR to add JustMock to the suite of performance tests that currently exist in that repository. The problem is that some of the tests (like OneParameter and Callback) take a long time to finish for JustMock. I'm not sure why, but it's making it such that JustMock can't be added to the test suite. More to the point, the PR can't be accepted as-is because it would take too long to finish.

One thing Steve (owner of the repo) and I talked about is if the invocationCount value passed to the SimpleJobAttribute (which exists on both the MockingBenchmark and MockingBenchmark<T> classes) is reduced from 100,000 to something like 1,000, the tests then finish, but that doesn't address the underlying issue why these tests for JustMock slow down over repeated called.

There may be something in the benchmark tests with the way I've set things up with JustMock that may be incorrect. I've never used JustMock until today :). If there's something that I'm doing right, please let me know.

Last Updated: 23 Sep 2021 14:25 by ADMIN
A System.InvalidProgramException is thrown when async unit tests are executed inside Visual Studio with code coverage. The unit tests are testing an implementation of Microsoft.Extensions.Caching.Distributed.IDistributedCache.
Last Updated: 16 Sep 2021 08:40 by ADMIN
Created by: Calvin
Comments: 3
Type: Bug Report

I filed a prior ThreadLeak:

Thread leak in JustMock (telerik.com)


I think I've found another one: (VS version 16.10.31321.278)


Apparently, the MonitorTimer_Elapsed code is running on a threadpool thread and it takes longer than 1 sec (perhaps it's waiting on a lock?).

Another timer tick occurs and the method is called again. Eventually, the ThreadPool runs out of threads and grows by about 1 thread per second (1Mb /sec leak)

In one dump 2Gig was used (1962 threads on the same MonitorTimer_Elapsed stack frame)

In that same dump there were 52 stacks with this frame:


(this was the same item as my prior report).


Last Updated: 16 Sep 2021 08:38 by ADMIN

The following test fails:

public void TestCallOrderWithInOrder()
	// Arrange
	var mockClass1 = Mock.Create<Class1>();
	var mockClass2 = Mock.Create<Class2>();

	Mock.Arrange(() => mockClass1.Method1())
	Mock.Arrange(() => mockClass2.Method1())
	Mock.Arrange(() => mockClass1.Method2())

	// Act

	mockClass2.Method1(); // <--- this call is not allowed by
						  //      InOrder clause currently 
						  //      and throws AssertFailedException


	// Assert

Last Updated: 16 Sep 2021 08:37 by ADMIN

The following test is not working anymore since version JustMock_2021_2_615_4 but was working with JustMock_2021_1_326_1 and older versions:

public interface ITest
    void Test(string text);

public void MyTestMethod()
    var mock = Mock.Create<ITest>();
    Mock.Arrange(() => mock.Test("")).IgnoreArguments().OccursNever();
    Mock.Arrange(() => mock.Test(Arg.Matches<string>(a => a == "a"))).InOrder().OccursOnce();
    Mock.Arrange(() => mock.Test(Arg.Matches<string>(a => a == "b"))).InOrder().OccursOnce();



If I remove the OccorsNever line, its working.
If I remove the 2 InOrder, its working.

Seems that something change there: https://www.telerik.com/support/whats-new/justmock/release-history/justmock-r2-sp1-2021

Last Updated: 17 Aug 2021 07:19 by ADMIN

Using elevated mocking mode (profiler enabled) with long path names for the test containers (above 260 characters) causes the following command:

dotnet test

to fail with error:

Testhost process exited with error: Fatal error. System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at Microsoft.VisualStudio.TestPlatform.TestHost.Program.Main(System.String[])
. Please check the diagnostic logs for more information.

Test Run Aborted.

Last Updated: 02 Jun 2021 11:42 by ADMIN

The documentation on Fluent Mocking ends with this statement:


Note that when you use Fluent Asserts only arrangements marked with either MustBeCalled or Occurs will be verified. For other tests you have to use the explicit assert.

What this fails to note is that, while this is true of the function "Assert", there is another function, "AssertAll", which will flag an error if any Arranged function call was not utilized.


On a related note, I left other suggestions for this same page a day or two ago.  I would have liked to leave the above statement using the same feedback utility, but I can no longer find the control that I used to leave those initial suggestions.

Last Updated: 26 May 2021 10:10 by ADMIN
String parameter "message" inside Mock.Assert APIs could be easily interpreted in the wrong way by associating them with the concrete assertion instead of the scope where this particular statement is taking place.
Last Updated: 18 May 2021 10:21 by ADMIN
JustMock Profiler prevents XAML Hot Reload and Visual Tree debugging functionalities. Disabling the profiler fixes the issue. This happens only for .NET Core WPF, under .NET Framework, everything runs as expected.
Last Updated: 13 May 2021 08:42 by ADMIN

We are trying to run unit tests via xUnit and mocking method occurence using JustMockLite. Method under arrange is creating a underlying Task however, once in a while test fails with following error


build	11-May-2021 14:36:09	               Telerik.JustMock.Xunit.AssertFailedException : Multiple assertion failures:
build	11-May-2021 14:36:09	               1. Occurrence expectation failed. Expected exactly 1 call. Calls so far: 0
build	11-May-2021 14:36:09	         Arrange expression: x => x.CallAsync(IsAny(), IsAny())
build	11-May-2021 14:36:09	               2. Occurrence expectation failed. Expected exactly 1 call. Calls so far: 0
build	11-May-2021 14:36:09	         Arrange expression: x => x.NotifyAsync(IsAny())
build	11-May-2021 14:36:09	               
build	11-May-2021 14:36:09	               ---- Telerik.JustMock.Diagnostics.DebugViewDetailsException : State:
build	11-May-2021 14:36:09	         Elevated mocking: disabled
build	11-May-2021 14:36:09	         
build	11-May-2021 14:36:09	         Arrangements and expectations:
build	11-May-2021 14:36:09	                   Arrangement (id=0) x => x.Load(IsAny()):
build	11-May-2021 14:36:09	                 Met: Occurences must be in [1, 1]; calls so far: 1. 
build	11-May-2021 14:36:09	             Arrangement (id=1) x => x.InitializePolicy(IsAny(), IsAny()):
build	11-May-2021 14:36:09	                 Met: Occurences must be in [1, 1]; calls so far: 1. 
build	11-May-2021 14:36:09	             Arrangement (id=2) x => x.RequestBulkSync(IsAny(), IsAny(), IsAny()):
build	11-May-2021 14:36:09	                 Met: Occurences must be in [any, 1]; calls so far: 1. 
build	11-May-2021 14:36:09	             Arrangement (id=3) x => x.CallAsync(IsAny(), IsAny()):
build	11-May-2021 14:36:09	                 Unmet: Occurences must be in [1, 1]; calls so far: 0. 
build	11-May-2021 14:36:09	             Arrangement (id=4) x => x.NotifyAsync(IsAny()):
build	11-May-2021 14:36:09	                 Unmet: Occurences must be in [1, 1]; calls so far: 0. 
build	11-May-2021 14:36:09	         
build	11-May-2021 14:36:09	         Invocations:

Last Updated: 04 May 2021 13:27 by ADMIN
Created by: Doug
Comments: 1
Type: Bug Report

s in a lot of webpages that point to whats good about just mock, except this link is broken, can you put in a redirect to the actual vids for just mock.

I currently use typemock, but looking for a team solution and having broken links and missing content implies product abandonment.

Where can I find the links to the current vid on just mock?



Last Updated: 26 Apr 2021 09:48 by ADMIN

Attempt to use JustMock VSTest v.2 task to run the elevated mode tests with coverage when the "Test platform version" option is set to value "Installed by Tools Installer" fails with error:

Telerik.JustMock.Core.ElevatedMockingException: Cannot mock '<target type goes here>'. The profiler must be enabled to mock, arrange or execute the specified target.
Detected active third-party profilers:
* {9317ae81-bcd8-47b7-aaa1-a28062e41c71} (from process environment)
Disable the profilers or link them from the JustMock configuration utility. Restart the test runner and, if necessary, Visual Studio after linking.

Last Updated: 18 Mar 2021 13:28 by ADMIN
When the ports with which the DebugWindow should operate are changed in the DebugWindow host configuration the process is started with the default values instead of the new values.
Last Updated: 05 Mar 2021 14:19 by ADMIN
The exception description does not clearly state that there is an issue with the member which is a target of the mocking which could easily lead to confusion. Attached sample project reproducing the issue.
Last Updated: 10 Feb 2021 11:10 by ADMIN

Having the following COM interop class

public class MyComObjectClass : IMyComObject, MyComObject
    public MyComObjectClass();

    public virtual string Echo(string message);

and the sample class that uses it:

public class MyComObjectClassProxy
    public string Echo(string message)
        IMyComObject itf = null;
            itf = new MyComObjectClass();
            return itf.Echo(message);
            if (itf != null)

When I try to call the arranged constructor I am getting an error "Cannot create instances of type requiring managed activation", the unit test code:

public void TestMethod1()
    var mock = Mock.Create<MyComObjectClass>();
    Mock.Arrange(() => new MyComObjectClass()).Returns(mock);

    var sut = new MyComObjectClassProxy();
    var actual = sut.Echo("Message");

    Assert.AreEqual(string.Empty, actual);
Last Updated: 02 Feb 2021 09:35 by ADMIN

I have a class, which has a private async method, which has a local function, like the following example


internal class TestClass



        private async Task<bool> TestPrivateMethod()
            var x = await TestLocalFunction();
            return x;

            async Task<bool> TestLocalFunction()
                await Task.Delay(5);
                return true;


When I try to mock the local function, thows an error "System.MissingMemberException : C# 7 local function 'TestLocalFunction' with the given signature was not found inside method 'TestPrivateMethod'"


var testClassInstance = Mock.Create<TestClass>(Behavior.CallOriginal);

Mock.Local.Function.Arrange<Task<bool>>(testClassInstance, "TestPrivateMethod", "TestLocalFunction").Returns(Task.FromResult(true));


Last Updated: 02 Feb 2021 09:32 by ADMIN
Created by: Calvin
Comments: 7
Type: Bug Report

Thread leak in JustMock

I am a member of the Visual Studio Perf Reliability team


Recently, I’ve found several customer dumps with huge # of threads.

In this dump:

Watson : Cab Search (microsoft.com)





Progress® Telerik® JustMock Feedback Portal


There are 2084 threads using 2G mem, most with the stack below:

This is caused by threadpool starvation: the JustMock call ties up a thread for more than 1 second, then another request comes in.

The CLR will create an additional thread after 1 second to satisfy the request. This keeps happening and creates thousands of threads, each with size 1Meg.


00 ntdll!NtWaitForMultipleObjects
01 KERNELBASE!WaitForMultipleObjectsEx
02 clr!WaitForMultipleObjectsEx_SO_TOLERANT
03 clr!Thread::DoAppropriateAptStateWait
04 clr!Thread::DoAppropriateWaitWorker
05 clr!Thread::DoAppropriateWait
06 clr!SOIntolerantTransitionHandler::SetNoException
07 clr!CLREventBase::WaitEx
08 clr!CLREventBase::Wait
09 clr!AwareLock::EnterEpilogHelper
0a clr!ThreadDebugBlockingInfo::PopBlockingItem
0b clr!DebugBlockingItemHolder::{dtor}
0c clr!AwareLock::EnterEpilog
0d clr!AwareLock::Enter
0e clr!AwareLock::Contention
0f clr!JITutil_MonReliableContention
10 Telerik_JustMock_DebugWindow_Service_Client!Telerik.JustMock.DebugWindow.Service.Client.ConnectionSetupServiceClientBase<Telerik.JustMock.DebugWindow.Service.Proxy.TraceEventsSubscriptionServiceProxy>.get_ServiceAvailable
11 Telerik_JustMock_DebugWindow_Service_Client!Telerik.JustMock.DebugWindow.Service.Client.SessionServiceClientBase<Telerik.JustMock.DebugWindow.Service.Proxy.MockRepositorySubscriptionServiceProxy>.KeepAliveTimer_Elapsed
12 System_ni!System.Timers.Timer.MyTimerCallback
13 mscorlib_ni!System.Threading.TimerQueueTimer.CallCallbackInContext
14 mscorlib_ni!System.Threading.ExecutionContext.RunInternal
15 mscorlib_ni!System.Threading.ExecutionContext.Run
16 mscorlib_ni!System.Threading.TimerQueueTimer.CallCallback
17 mscorlib_ni!System.Threading.TimerQueueTimer.Fire
18 mscorlib_ni!System.Threading.TimerQueue.FireNextTimers
19 mscorlib_ni!System.Threading.TimerQueue.AppDomainTimerCallback
1a clr!CallDescrWorkerInternal
1b clr!CallDescrWorkerWithHandler
1c clr!MethodDescCallSite::CallTargetWorker
1d clr!MethodDescCallSite::Call
1e clr!AppDomainTimerCallback_Worker
1f clr!ManagedThreadBase_DispatchInner
20 clr!ManagedThreadBase_DispatchMiddle::__l16::Cleanup::{dtor}
21 clr!ManagedThreadBase_DispatchMiddle
22 clr!ManagedThreadBase_DispatchOuter
23 clr!ManagedThreadBase_FullTransitionWithAD
24 clr!ManagedThreadBase::ThreadPool
25 clr!AppDomainTimerCallback
26 clr!ThreadpoolMgr::AsyncTimerCallbackCompletion
27 clr!UnManagedPerAppDomainTPCount::DispatchWorkItem
28 clr!ThreadpoolMgr::ExecuteWorkRequest
29 clr!ThreadpoolMgr::WorkerThreadStart
2a clr!Thread::intermediateThreadProc
2b kernel32!BaseThreadInitThunk
2c ntdll!__RtlUserThreadStart
2d ntdll!_RtlUserThreadStart

Last Updated: 02 Feb 2021 09:30 by ADMIN
Created by: Eric
Comments: 7
Type: Bug Report

when using JustMock Free in a net 5.0 app.  I am getting an Ninject exception that IAssemblyNameRetriever could not be found.  Looking at the code on github,

the NETCORE compile constant removes the line

AddComponent<IAssemblyNameRetriever, AssemblyNameRetriever>();

from StandardKernel.cs

however, CompiledModuleLoaderPlugin uses IAssemblyNameRetriever in it's constructor and

AddComponent<IModuleLoaderPlugin, CompiledModuleLoaderPlugin>();

is still included in the NETCORE version.



Last Updated: 02 Feb 2021 09:25 by ADMIN
The issue is reproducible inside Visual Studio 2017, the same tests are running normaly outside the IDE or using 2019.
Last Updated: 01 Feb 2021 09:56 by ADMIN
Created by: Maxim
Comments: 1
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.
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