Unplanned
Last Updated: 27 Jun 2025 14:07 by Ivo

To replicate the problem using the provided project, follow these steps:

1. Open the solution in Rider.
2. Set breakpoints at the beginning of the test.
3. Start debugging the test.
4. Step into the constructor of the Car class and inspect the contents of the array. Note that if this step is skipped, the issue will not be reproducible.
5. Step out of the constructor.
6. Continue execution until just before calling the virtual function for the Number property.
7. Step into the function.

**EXPECTED** The value of Name should be visible.

**ACTUAL** A debugger error occurs.

The issue can appear in both Visual Studio (showing "Internal error in the C# compiler") and Rider (showing "Read out of bounds"). 


Completed
Last Updated: 17 Jun 2025 11:26 by ADMIN

The test run is aborted when a .testsettings is used for executing JustMock tests. The .testsettings contains only a description.

<?xml version="1.0" encoding="UTF-8"?>
<TestSettings name="Local" id="15694c75-be1c-4113-9d42-2cbe1013c41c" xmlns="http://microsoft.com/schemas/VisualStudio/TeamTest/2010">
  <Description>These are default test settings for a local test run.</Description>
</TestSettings>

 

It seems that the usage of the MSTest element is breaking the execution.

Workaround: As .testsettings are deprecated use .runsettings instead without MSTest element.

Completed
Last Updated: 27 May 2025 15:39 by ADMIN
Release 2025 Q3

My setup includes my local dev environment and so called "grid node" server used by NCrunch.

Yesterday I've updated JustMock to version 2025.2.520.440.
After that update I received an error mentioning my License file not to include Telerik Just Mock.
So I've updated my License file by the way mentioned in the Release Notes.

After that my NCrunch Build crashed with an TypeInitializationException "The type initializer for 'Telerik.JustMock.Core.Licensing.LicenseManager'. String was not recognized as a valid DateTime."

I've updated my License file again today and the Exception Message has changed to "String '5/20/2025' was not recognized as a valid DateTime."

I than set my local DateDime format from dd.MM.yyyy to yyyy-MM-dd and the problem is gone.
So it seems like the current version has a problem with our German / European format.

With version 2025.1.211.365 everything worked fine.

So would you please so kind to have a look onto that?
Thank you

 

Unplanned
Last Updated: 22 May 2025 12:53 by ADMIN
Scheduled for 2025 Q3
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.
Planned
Last Updated: 22 May 2025 12:25 by ADMIN
Scheduled for 2025 Q3

We're using this DevOps task in our pipeline, however since yesterday we get the following warning:

##[warning]Task 'Telerik JustMock VSTest v.2' version 2 (JustMockVSTest@2) is dependent on a Node version (6) that is end-of-life. Contact the extension owner for an updated version of the task. Task maintainers should review Node upgrade guidance: https://aka.ms/node-runner-guidance

 

We're running it using a build agent hosted at the Azure DevOps cloud.

Won't Fix
Last Updated: 22 Apr 2025 11:25 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:

Won't Fix
Last Updated: 02 Apr 2025 14:21 by ADMIN

Hello

I generate a syntax tree which I will format with Formatter.Format() from the package Microsoft.CodeAnalysis.CSharp.Workspaces 4.4.0 and .NET 6. A test exists where the formatter is used but when the JustMock profiler is enabled an InvalidProgramException is thrown. When the profiler is disabled everything works fine. It fails on Windows and on Linux.

Exception

  Message: 
System.InvalidProgramException : Common Language Runtime detected an invalid program.

  Stack Trace: 
ContextIntervalTree`2.ctor(TIntrospector& introspector)
FormattingContext.ctor(AbstractFormatEngine engine, TokenStream tokenStream)
AbstractFormatEngine.CreateFormattingContext(TokenStream tokenStream, CancellationToken cancellationToken)
AbstractFormatEngine.Format(CancellationToken cancellationToken)
CSharpSyntaxFormatting.Format(SyntaxNode node, SyntaxFormattingOptions options, IEnumerable`1 formattingRules, SyntaxToken startToken, SyntaxToken endToken, CancellationToken cancellationToken)
AbstractSyntaxFormatting.GetFormattingResult(SyntaxNode node, IEnumerable`1 spans, SyntaxFormattingOptions options, IEnumerable`1 rules, CancellationToken cancellationToken)
Formatter.GetFormattingResult(SyntaxNode node, IEnumerable`1 spans, Workspace workspace, OptionSet options, IEnumerable`1 rules, CancellationToken cancellationToken)
Formatter.Format(SyntaxNode node, IEnumerable`1 spans, Workspace workspace, OptionSet options, IEnumerable`1 rules, CancellationToken cancellationToken)
Formatter.Format(SyntaxNode node, Workspace workspace, OptionSet options, CancellationToken cancellationToken)
UnitTest1.Test1() line 23

Reproduction

You can reproduce this by writing an unit test for that (I used xUnit):

        [Fact]
        public void Test1()
        {
            var classText = @"using System; namespace TestNameSpace.Orders { public class Order
                            {
                                public Guid Id { get; set; }
                            }
                        }";

            var syntaxTree = CSharpSyntaxTree.ParseText(classText);
            var workspace = new AdhocWorkspace();

            var formattedClassText = Formatter.Format(syntaxTree.GetRoot(), workspace).ToFullString();

            var expected = @"using System;
namespace TestNameSpace.Orders
{
    public class Order
    {
        public Guid Id { get; set; }
    }
}";
            Assert.Equal(expected, formattedClassText);
        }
    }

System Info

JustMock

See attachments. We do not use the free edition.

.NET

dotnet --info
.NET SDK:
 Version:   7.0.200
 Commit:    534117727b

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19045
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\7.0.200\

Host:
  Version:      7.0.3
  Architecture: x64
  Commit:       0a2bda10e8

.NET SDKs installed:
  6.0.406 [C:\Program Files\dotnet\sdk]
  7.0.200 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 6.0.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 6.0.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 6.0.14 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

 

I already posted a question but can't delete it anymore: InvalidProgramException thrown when formatting SyntaxNodes in JustMock | Telerik Forums
Completed
Last Updated: 15 Nov 2024 09:35 by ADMIN
Created by: Ivo
Comments: 1
Type: Bug Report
2

With R3 2023 (2023.3.1011.155) JustMock introduces a new functionality that might lead to a huge performance drop and event to unexpected failures. Currently, the issue could be suppressed by setting up an environment variable JUSTMOCK_NEWOBJ_INTERCEPTION_ON_OVERWRITE_ENABLED to 0 (the default value is 1), but a more reliable and independent solution should be found.

Completed
Last Updated: 21 Aug 2024 14:04 by ADMIN

if you use the C# using declaration and have JustMock advanced (elevated) mode enabled, the runtime will throw an InvalidProgramException.

Find below the sample code that demonstrates the issue:

public class TestClass : IDisposable
{
    public void Dispose()
    {
    }
}

[TestClass]
public class Fixture
{
    public interface ITest { }

    [TestMethod]
    public async Task Test()
    {
        ITest mock = Mock.Create<ITest>();
        using TestClass test = new();
    }
}

Completed
Last Updated: 13 Aug 2024 14:52 by ADMIN

Having the simple class

public class MyClass
{
    public event Func<EventArgs, Task>? MyEventAsync;
}
and the test that tries to rise the declared event
[TestMethod]
public void TestMethod1()
{
    var mockClass = Mock.Create<MyClass>(Behavior.Strict);
    mockClass.MyEventAsync += (args) => Task.CompletedTask;

    Mock.Raise(() => mockClass.MyEventAsync += null, EventArgs.Empty);
}

Execution triggers the following error:

Telerik.JustMock.Core.MockException : Event signature System.Threading.Tasks.Task OnMyEventAsync(System.EventArgs) is incompatible with argument types (Castle.Proxies.ExternalMockMixinProxy, System.EventArgs)

which is kind of unexpected since the supplied arguments are matching to the event's signature.

 

Unplanned
Last Updated: 08 Feb 2024 18:32 by Ivo

The issue is about interoperability between JustMock and AutoFixture. The unit test run can be 90% faster if all the fixtures are created before the JustMock arrangements.

Here is a sample code that figures out the issue:

[Fact]
public void Slow
{ 
    var fixture = new Fixture():

    var items1 = fixture.Create<List<Item>>();
    Nock.Arrange(() => ItemsRepository.GetItems1()).Returns(items1);

    var items2 = fixture.Create<List<Item>>();
    Nock.Arrange(() => ItemsRepository.GetItems2()).Returns(items2);

    var items3 = fixture.Create<List<Item>>();
    Nock.Arrange(() => ItemsRepository.GetItems3()).Returns(items3);

    var items4 = fixture.Create<List<Item>>();
    Nock.Arrange(() => ItemsRepository.GetItems4()).Returns(items4);
}

[Fact]
public void Fast()
{
    var fixture = new Fixture():

    var items1 = fixture.Create<List<Item>>();
    var items2 = fixture.Create<List<Item>>();
    var items3 = fixture.Create<List<Item>>();
    var items4 = fixture.Create<List<Item>>();

    Nock.Arrange(() => ItemsRepository.GetItems1()).Returns(items1);
    Nock.Arrange(() => ItemsRepository.GetItems2()).Returns(items2);
    Nock.Arrange(() => ItemsRepository.GetItems3()).Returns(items3);
    Nock.Arrange(() => ItemsRepository.GetItems4()).Returns(items4);
}

The test duration should not be dependent on the exact implementation.

Unplanned
Last Updated: 05 Feb 2024 13:46 by Christian
When mock generation is enabled and a mock code ends with unfinished Return setup VB compiler get into a broken state. Once in broken state the user has to manually build the code or go back in code editor in order to get into correct state.
Completed
Last Updated: 17 Oct 2023 12:33 by ADMIN

Considering the sample class

using Azure.Messaging.ServiceBus;

public class Class2
{
	private static ServiceBusSender messageToTopicSender;
	private static string topicName;

	public static void SetRequestTopicClient(string serviceBusConnectionString, string topName)
	{
		topicName = topName;

		ServiceBusClient serviceBusClient = new ServiceBusClient(serviceBusConnectionString);
		messageToTopicSender = serviceBusClient.CreateSender(topicName);
	}
}

and the following tests

[TestClass]
public class Class1Test
{
	[TestInitialize]
	public void SetUp()
	{
		Mock.Arrange(() => Class2.SetRequestTopicClient("", "")).DoNothing();
	}

	[TestMethod]
	public void TestA()
	{
		Class2.SetRequestTopicClient("", "");
	}
}

[TestClass]
public class Class2Test
{
	static ServiceBusClient serviceBusClient = Mock.Create<ServiceBusClient>();
	ServiceBusSender messageToTopicSender = Mock.Create<ServiceBusSender>();

	[TestInitialize]
	public void SetUp()
	{
		Mock.Arrange(() => new ServiceBusClient("conStr")).Returns(serviceBusClient);
		Mock.Arrange(() => serviceBusClient.CreateSender("myTopic")).Returns(messageToTopicSender);
	}

	[TestMethod]
	public void TestB()
	{
		Class2.SetRequestTopicClient("conStr", "myTopic");
	}
}

Executing the tests in order TestA -> TestB results in failed TestB, but changing the order or runining them standalone succeeds.The outcome of the tests should not be dependent of the execution order.

 

Completed
Last Updated: 17 Oct 2023 12:32 by ADMIN
Created by: Ivo
Comments: 1
Type: Bug Report
1

A unit test run against a simple class using EntityFramework never completes, here's the code:

public class DbContext1 : DbContext
{
    public DbContext1(string connectionString)
    {
    }
}

public class Program
{
    private static readonly SemaphoreSlim _lock = new SemaphoreSlim(1, 1);

    public async Task Run()
    {
        await _lock.WaitAsync();
        try
        {
            await InsertDbRow();
        }
        finally
        {
            _lock.Release();
        }
    }

    private static async Task InsertDbRow()
    {
        await RetryWrapperAsync(async () =>
        {
            using DbContext1 dbContext = new DbContext1("con str");
            await dbContext.SaveChangesAsync();
        });
    }

    public static async Task RetryWrapperAsync(Func<Task> operation)
    {
        for (int i = 0; i < 3; i++)
        {
            try
            {
                await operation();
                break;
            }
            catch (Exception)
            {
                await Task.Delay(100);
            }
        };
    }
}

[TestClass]
public class ProgramTest
{
    private readonly DbContext1 mockContext1 = Mock.Create<DbContext1>();

    [TestInitialize]
    public void SetUp()
    {
        Mock.Arrange(() => new DbContext1("con str")).Returns(mockContext1);
    }

    [TestMethod]
    public async Task TestMethod()
    {
        // Arrange
        Program program = new Program();

        // Act
        await program.Run(); // <-- at this point the test hangs
    }
}

Adding do-nothing arrangement on mockContext.SaveChanges fixes the hang, but the expectation is that mock will handle this case by default and there is no need to be explicitly arranged.

Unplanned
Last Updated: 23 Jun 2023 09:42 by ADMIN

Dear Telerik team,
It is nice to have a way to generate mocks.

But it is annoying to have lots of those messages for references in XML comments. I had to turn the feature off. Which might be the case for other customers too.

Maybe you want to have a look into it.


Declined
Last Updated: 16 May 2023 07:45 by ADMIN

I am unable to mock interfaces that contain a method with an `in` parameter. When running the following code snippet, the result is an exception:

Message: 
  Test method Example.UnitTests.UnitTest.TestMethod threw exception:
  Telerik.JustMock.Core.MockException: Abstract type 'Example.UnitTests.InParamExample' is not accessible for inheritance.

Stack Trace: 
  MocksRepository.Create(Type type, MockCreationSettings settings)
  <>c__38`1.<Create>b__38_0()
  ProfilerInterceptor.GuardInternal[T](Func`1 guardedAction)
  UnitTest.TestMethod() line 23

namespace Example.UnitTests
{
    using Microsoft.VisualStudio.TestTools.UnitTesting;
    using Telerik.JustMock;

    public interface ParamExample
    {
        void Foo(int param);
    }

    public interface InParamExample
    {
        void Foo(in int param);
    }

    [TestClass]
    public class UnitTest
    {
        [TestMethod]
        public void TestMethod()
        {
            var mockedParamExample = Mock.Create<ParamExample>();
            var mockedInParamExample = Mock.Create<InParamExample>();
        }
    }
}
Completed
Last Updated: 12 May 2023 09:34 by ADMIN

Mock.Create<IPool>() fails with 

Telerik.JustMock.Core.MockException : Abstract type 'IPool' is not accessible for inheritance.
   In Telerik.JustMock.Core.MocksRepository.Create(Type type, MockCreationSettings settings)
   In Telerik.JustMock.Mock.<>c__39`1.<Create>b__39_0()
   In Telerik.JustMock.Core.ProfilerInterceptor.GuardInternal[T](Func`1 guardedAction) 

when trying to create a mock object from

public interface IPool
{
    object GetItem(in Struct a, out Class b);
}

 

Completed
Last Updated: 05 May 2023 06:59 by ADMIN
The issue has been detected for the first time in an attempt for integration between dotTrace 2022.3.2 and JustMock 2023.R1, but it also applies to dotCover and all subsequent versions after 2022.3 of both products.
Unplanned
Last Updated: 13 Apr 2023 08:40 by Ivo

The following code snippet causes a hang in the test execution while being debugged:

Mock.SetupStatic(typeof(TimeSpan), Behavior.CallOriginal, StaticConstructor.NonMocked);
Mock.Arrange(() => TimeSpan.FromSeconds(15)).Returns(TimeSpan.MinValue);

The issue can be temporary solved by disabling the DebugWindow via JustMock extension menu. 

Completed
Last Updated: 14 Mar 2023 13:08 by Adam

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.

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