'Visual Studio - suddenly cannot debug tests

I'm not sure what I did, but all of a sudden, my Visual Studio 2012 will not debug any tests.

If I select a test from the Test Explorer and tell it to run, it simply outputs this in the Test Output window:

> ------ Discover test started ------
> ========== Discover test finished: 29 found (0:00:01.3371755) ==========
> ------ Run test started ------ Process with an Id of -1 is not running.
> ========== Run test finished: 0 run (0:00:01.4711861) ==========

what the heck does that mean?! After doing this a few times, the error changed to:

The Operation was Cancelled

which I sure didn't do.

It's doing this on every test in the list.

however, I can RUN the tests no problem, and they pass... but I cannot debug the tests.

What might I have done? I did not actively go into any settings and change anything, perhaps a stray click somewhere, but where?

Solution 1:^[1]

I encountered this today. I tried closing the solution but it didn't work. My mistake I set my solution to Release Mode instead of Debug Mode. I set it to Debug then it worked as expected.

I'm using VS 2015 professional.

Solution 2:^[2]

I was getting the same output after upgrading a test project from VS 2010 to VS 2012 Ultimate Update 3. The message was displayed in Test Output window after using MSTest command to Debug Selected Tests.

I tried to debug tests using Resharper 8 Unit Test Session window. The message in the result window was "Test wasn't run".

The solution that helped me was to modify the test project settings to enable native code debugging as instructed at this link: Uncaught exception thrown by method called through reflection

In case the link does not work:

Go to the project right click and select properties.
Select 'Debug' tab on the left.
Go to ‘Enable Debuggers’ on the bottom
Check ‘Enable Native code debugging’ (or 'Enable unmanaged code debugging', depends on version) check box

Thanks to GalDude33 for posting the solution.

Solution 3:^[3]

Have regularly the same issue with Visual Studio 2012.

Solution : close the current solution and reopen it.

In my case closing and reopening VS was not necessary.

Solution 4:^[4]

Async Tests - Symptoms in my scenario were similar in that my test was not executing and my breakpoint was not getting hit. The Test Explorer in Visual Studio could see the test, but I could not debug it. Running it acted as though it could not be found even though it could be seen in the Test Explorer.

In case it helps someone else, my issue was as simple as having to change the test method's signature from "async void" to "async Task".

Do this:

[TestMethod]
public async Task CorrectlyFailingTest()
{
  await SystemUnderTest.FailAsync();
}

Not this:

[TestMethod]
public async void CorrectlyFailingTest()
{
  await SystemUnderTest.FailAsync();
}

Solution 5:^[5]

In my case, it was the launchSettings.json file which was causing the debugger not to be able to hit a breakpoint. Not sure why the file was present in a unit test type of project (probably some unwanted leftover), however, xunit seemed not to ignore it. I simply deleted the file and I was able to debug the unit tests again.

Env: Microsoft Visual Studio Enterprise 2019 Preview (Version 16.8.0 Preview 3.1)

Solution 6:^[6]

I was unable to attach to my debugger because it was looking for test settings file.
If this is your issue then go to Test->Test Settings->Uncheck Local.testsettings option

Solution 7:^[7]

Please follow below steps. It worked for me

Steps.

1.Close your visual studio instances

2.Clean you temp files and prefetch files.

3.delete the files in project bin folder.

4.Restart the applications.

Solution 8:^[8]

Ensure your test project is part of the projects to build.

Right click your solution from Solution Explorer
Go to Set StartUp Projects..
Click on Configuration Properties and ensure your test project is checked for build

Solution 9:^[9]

For me, updating MSTest.TestAdapter and MSTest.TestFramework Nuget packages to latest version resolved the problem.

Solution 10:^[10]

I was having similar issue in VS2015. Only one unit test could not be debugged in my case. Debugger would initialize a test, but would not debug test itself, nicely exiting. The problem was in Resharper importing Newtonsoft.Json library without enabling NuGet package for the project. (I used Alt+Enter to automatically import the library)

Solution was to install Newtonsoft.Json NuGet package for test project.

Solution 11:^[11]

As of Visual Studio 2017 (15.8), this can happen when the Live Unit Testing feature is active. There's no clear message in the output; it just starts and stops without debugging. The solution is stopping the live testing so then you can debug the test normally.

Solution 12:^[12]

In my case, my symbols weren't loaded.

I had to go to Tools -> Options -> Debugging -> Symbols and select "Load all modules, unless excluded" for breakpoints to get hit.

Solution 13:^[13]

Take a look at the following link there is an update that fixing it. Visual studio 2012 update 3.

http://social.msdn.microsoft.com/Forums/vstudio/en-US/e96f53c7-dc8c-4274-8756-eb745de701e8/visual-studio-2012-update-3-cant-debug-unit-test

Solution 14:^[14]

When I use Visual Studio 2012, for some reasons, if I use shortcut ctrl R+T, it will hit the break point. But if I click "Run All" or "Run Selected Test" on Test Explorer, it won't. Visual Studio 2013 works fine both ways though.

Solution 15:^[15]

Hitting "Run tests" will not trigger the brakepoints.

To debug your code and stop at a breakpoint in a test:

Right-click > Debug Tests

"Test" tab > Debug > All tests

Solution 16:^[16]

This might not be a solution to your problem specifically, but I also couldn't debug a test that I had written. Turns out the solution was quite simple:

Change the method from private to public. I don't know why debugging isn't possible within private methods, but it's probably got something to to with the [Test] attribute's implementation. Hope this helps anyone struggling with a similar problem in the future!

Solution 17:^[17]

None of the proposed solutions worked for me. What worked for me is changing the unit test project and all dependent projects' platform target to Any CPU instead of x64 which is some kind of a workaround not a real fix !!

EDIT

The target platform for a unit test project could be changed from test settings not from the project's properties. Refer to this answer for more.

Solution 18:^[18]

Just like you guys, I wasn't able to Debug nor Run Unit Tests of my MSBuild Tests Project in Visual Studio 2019 16.6.2. The code I wanted to Unit Test is in a Class Library based on .Net 4.6.2. The Test Explorer always stated "Tests Not Run" with the blue information icon beneath.

So I just tried to create a new Unit Test from within the Code File of the Method I wanted to test => and it worked! Exact steps I went through: In the C# File go to the method, right click on it and select "Create Unit Tests" and let the dialog create a new project. After adding the Test Code from my original files all went fine and I am able to Debug and Run my Test Methods!

Hope this simple solutions helps some of you, too. Best regards

Solution 19:^[19]

With me I simply added xunit.runner.visualstudio (latest stable version at the time was 2.4.2) and that did the trick.

Solution 20:^[20]

For me the problem was that my config file (app.config) didn't have the Debug Transformation file (app.Debug.config), once I added it start working/debugging again.

Solution 21:^[21]

For me the problem was that after upgrading to 2017 v15.5.7 my solution's properties got changed somehow. Which made it where I could run the test once in debug mode, but not again, unless I restarted VS, then it would work again, once. Once I set it back it worked again. The setting was, and should be, for me, Solution > Common Properties > Startup Project > Multiple startup projects. Somehow it got set to "Single startup project".

Solution 22:^[22]

Check that the test project and the main project are using the same framework version.

Solution 23:^[23]

Solution: Select 'Debug Unit Tests' or 'Run Unit Tests' instead of 'Debug Tests' or 'Run Tests'.

Solution 24:^[24]

app.config problem references can unwittingly cause the debugger not to attach and breakpoints not to be hit when debugging test projects. This file may have been updated by packages or has gone out of date.

Solution: I generally copy then remove all dependencies under the runtime tag from the test project's app.config. Debugging usuually starts working after this but some references may need to be added back if assemblies can't be found.

Solution 25:^[25]

In my case, the break point can't be hit if there is build warning(s). I can verify this by toggle the line of code with warning. It was a unused string with length 66000. (Warning CS0219 The variable 'XXXXXXX' is assigned but its value is never used)

I guess the compiler removed this line so the symbol mapping failed?

Solution 26:^[26]

For me the following worked:

Close Solution
Close Visual Studio
Delete the contents of "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files\"
Delete the contents of "C:\Windows\Microsoft.NET\Framework64\v2.0.50727\Temporary ASP.NET Files\"
Open Visual Studio
Open Solution

Solution 27:^[27]

I just faced a similar issue, where NUnits TimeoutAttribute caused the test to be cancelled when debugging without a meaningful message.

Removing the attribute from the test fixed the issue.

Solution 28:^[28]

If you created a project in an older Visual Studio and are now using VS 2019, you must install the Microsoft.VisualStudio.TestPlatform library and update others.

Solution 29:^[29]

In my case, it was because I was using a non-static method as the dynamic data source for a Data test method.

Solution 30:^[30]

For me I went to Test explore -> setting -> processor Architecture For AnyCPUProjects and changed it to X64 and it worked for me.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	Tom Mabaquiao
Solution 2	Community
Solution 3	Pragmateek
Solution 4	Paul Schroeder
Solution 5	rocky
Solution 6	Matthew Peterson
Solution 7	Om Sao
Solution 8	Peter Ombwa
Solution 9
Solution 10	user2957464
Solution 11	Arturo Torres Sánchez
Solution 12	Hanlet EscaÃ±o
Solution 13	user2682517
Solution 14	paibamboo
Solution 15	Chris Mathew
Solution 16	Andreas ForslÃ¶w
Solution 17
Solution 18	Cordt
Solution 19	Dharman
Solution 20	Jaider
Solution 21	Shawn Smith
Solution 22
Solution 23	Ravi Kant Shivhare
Solution 24
Solution 25
Solution 26	wh1tet1p
Solution 27	nozzleman
Solution 28	H2Oc
Solution 29	Eric
Solution 30	Gaurav Joshi

'Visual Studio - suddenly cannot debug tests

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