Visual Studio 2015 or 2017 does not discover unit tests

Question

EDIT 2016-10-19   The original question was about an issue specific to VS2015 CTP6 with the XUnit test runner  It s clear from the answers that there is a much broader issue with unit test discovery in Visual Studio which may occur in many different situations  I have cleaned up my question to reflect that   I have also included a script in my own answer that I still use to this day to solve similar problems when they appear   Many other answers have also proven helpful in better understanding the intricacies of the VS test runner  I appreciate that people are still sharing their solutions     Original question 2015-04-10   Since yesterday  my Visual Studio Test Explorer won t discover tests for any of my projects  It does not show the green loading bar after building  either   When I go to the Visual Studio Test Explorer and click  Run All   or when I right-click any test method and select  Run Tests   I get the following in my output window   Could not load file or assembly  Microsoft VisualStudio Web ProjectSystem  Version 14 0 0 0  Culture neutral  PublicKeyToken b03f5f7f11d50a3a  or one of its dependencies  The system cannot find the file specified   I am running Visual Studio 2015 CTP 6 on Windows 10 Pro Technical Preview  build 10041  The  NET Framework version does not seem to matter - it happens on 4 0  4 5 2 and 4 6   I tried with the following testing frameworks and all of them give the same behavior    Microsoft VisualStudio QualityTools UnitTestFramework v14 0 22609 0 xunit v2 1 0-beta1-build2945 with xunit runner visualstudio v2 1 0-beta1-build1051 NUnit v2 6 4 with NUnitTestAdapter v2 0 0     I found an issue on GitHub  xunit  that appeared to be similar  Cannot get tests discovered  295  with this comment from the xunit team      Be aware that Visual Studio 2015 CTP 5 has been reported to be broken   by many people with unit testing in general  not just xUnit net   so   don t expect that to work       Also  please make sure you ve cleaned out Visual Studio s runner   cache  If it gets corrupted  Visual Studio will permanently misbehave   until it s deleted  To clear the cache  shut down all instances of   Visual Studio  then delete the folder    TEMP  VisualStudioTestExplorerExtensions  honestly  it probably   wouldn t hurt to delete everything in  TEMP  that can be deleted     I tried their suggestion to delete the folder  TEMP  VisualStudioTestExplorerExtensions  Unfortunately that did not fix the problem   I noticed that ReSharper actually is able to discover some tests  It only works for the VS and NUnit tests  not for xunit   There has to be some sort of temp or cache folder I need to clear  but I know Visual Studio has many of them and not all of them can be deleted without unwanted side-effects

User · Answer

I was also bitten by this wonderful little feature and nothing described here worked for me. It wasn't until I double-checked the build output and noticed that the pertinent projects weren't being built. A visit to configuration manager confirmed my suspicions.

Visual Studio 2015 had happily allowed me to add new projects but decided that it wasn't worth building them. Once I added the projects to the build it started playing nicely.

User · Answer

I made the mistake of creating async methods but returning void   Changed  public async void Test    To  public async Task Test

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It was so easy for me to fix the issue as    Select your Unit Test Project Click on  Show All Files  button in the Solution Explorer and new temporary files appeared in the file tree of the Solution Explorer within  obj x86 Debug    Delete these temporary files and rebuild project  Retried to run tests and worked

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In my case  Visual Studio Enterprise 2015 14 0 25425 01 Update 3  Resharper 2016 2  I just needed to do a clean solution from the Build menu  Rebuilding the solution then cause the test explorer to  wake up  and find all the tests again

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For me the solution was cleaning and rebuilding the Test Project  Build   Clean  Build   Build  I haven t read that in the answers above  that s why I add it

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I believe you already found the issue  but in my case helped to simply install the Microsoft NET Test Sdk  Make sure you add it to your test project  I ve spent few days trying to solve the problem and it s as simple as that  Microsoft Net Test Sdk should be installed no matter what testing framework you are using  https   i imgur com Ol6AoOm png

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For me upgrading to version 3 7 of NUnit worked

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This probably won t help most people  but someone inexperienced at unit testing had written a test method that returned bool instead of void    TestMethod  public bool TestSomething     Changing the return type to void fixed the problem

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This topic is somewhat outdated  but my solution to the missing Test status in VS2015   The task-status only shows up on the Debug buildconfiguration  Ofcourse this also makes it impossible to debug your test through the test-explorer

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Go to Nuget package manager and download Nunit Adapter as follow

User · Answer

Just restart Visual Studio and in Test Explorer do  Run All      All my tests are discovered then

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I don t have a complete answer to this  but I have determined some things by playing with a test project    The xunit runner aspnet   2 0 0-aspnet-beta4 that appears to be part of the official beta4 aspnet5 release does not work in Visual Studio  Instead  using  xunit    2 1 0-   and  xunit-runner dnx    2 1 0-   packages DO work in Visual Studio  In order for VS to discover the tests  your project MUST have a SINGLE command named  test  that runs  xunit runner dnx    Adding additional commands may break it  If your Test Explorer window still ends up empty  REMOVE the  test  command from your project  then re-build the solution  then add the  test  command back to the project json  Clearing all your caches as per  Fred-Kleuver  s suggestion may help  but I haven t done all the steps in isolation  so I m not sure    This is current as per VS 2015 CTP 6  using the beta4 releases  not the dailies

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Somehow my project was set to compile as a Static Library   lib   After changing this to a Dynamic Library   dll   tests where discovered correctly by Visual Studio 2012   My Unit Test Project - gt  Properties - gt  Configuration Properties - gt  General - gt  Configuration Type

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EDIT 2016-10-19  PowerShell script   This issue still returns every now and then  I wrote a small PowerShell snippet to automate clearing the relevant cache temp folder files for me  I m sharing it here for future readers        env TEMP    env LOCALAPPDATA Microsoft UnitTest    env LOCALAPPDATA Microsoft VisualStudio 14 0 1033 SpecificFolderCache xml    env LOCALAPPDATA Microsoft VisualStudio 14 0 1033 ProjectTemplateMRU xml    env LOCALAPPDATA Microsoft VisualStudio 14 0 ComponentModelCache    env LOCALAPPDATA Microsoft VisualStudio 14 0 Designer ShadowCache    env LOCALAPPDATA Microsoft VisualStudio 14 0 ImageLibrary cache    env LOCALAPPDATA Microsoft VisualStudio Services 6 0 Cache    env LOCALAPPDATA Microsoft WebsiteCache    env LOCALAPPDATA NuGet Cache         Remove-Item -Path    -Recurse -Force     Make sure to close Visual Studio beforehand and it s probably a good idea to reboot afterwards   Deleting the TEMP folder may not be necessary and may in some cases even be undesirable  so I would recommend trying without clearing the TEMP folder first  Just omit the   env TEMP    Original answer 2015-04-12  The problem was  solved  after a thorough cleaning of Visual Studio-related temp cache folders   Since I did not have the time to go through everything one-by-one and then test in-between  I unfortunately don t know which one actually caused the problem   These are the exact steps I ve taken    Closed Visual Studio Used CCleaner to clear system and browser temp files folders Manually cleared deleted the following files folders     USERPROFILE  AppData Local assembly  USERPROFILE  AppData Local Microsoft UnitTest  USERPROFILE  AppData Local Microsoft VisualStudio 14 0 1033 SpecificFolderCache xml  USERPROFILE  AppData Local Microsoft VisualStudio 14 0 1033 ProjectTemplateMRU xml  USERPROFILE  AppData Local Microsoft VisualStudio 14 0 ComponentModelCache  USERPROFILE  AppData Local Microsoft VisualStudio 14 0 Designer ShadowCache  USERPROFILE  AppData Local Microsoft VisualStudio 14 0 ImageLibrary cache  USERPROFILE  AppData Local Microsoft VisualStudio Services 6 0 Cache  USERPROFILE  AppData Local Microsoft WebsiteCache  USERPROFILE  AppData Local NuGet Cache  USERPROFILE  AppData Local Temp

User · Answer

Make sure your class with the  TestClass  attribute is public and not private

User · Answer

I had the same problem  I just cleaned and rebuilt the project and I was able to see the tests that were missing

User · Answer

Make sure your Test Methods do not have parameters   This is another way your test will not show up   No Errors or Warnings

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This happened to me because my test project contained an app config   It was automatically added by NuGet packages for assembly redirection  but my tests seemed to run fine without it    See  https   developercommunity visualstudio com comments 42858 view html

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I had an instance where some tests would not be picked up because I had made them async like the following   public async void This IsMy UnitTest    The problem was I forgot to make them return a Task and not void when I did the switch-over  One would think this would cause an error or failed test but nope  The unit tests in that class were fully ignored and acted like they didn t exist    It wasn t after about 3 clean and builds   restarting VS NET that I saw the test run and fail indicating I forgot to add the Task return type   public async Task This IsMy UnitTest    After the update  the unit tests were found and worked correctly  This might be an edge case  but having async tests for using await within but not having the signature correct can cause this same issue and it s not the 1st time I ve done this

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I resolved it by changing X64 to   Right click on project -  Properties -  Build -  Platform target -  Any CPU

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I had the same issue  The unit test template of Visual Studio 2015  Update 3  generates a class with TestContext property defined as follow       private TestContext testContextInstance            lt summary gt         Gets or sets the test context which provides        information about and functionality for the current test run          lt  summary gt      public TestContext TestContext               get                       return testContextInstance                    set                       testContextInstance   value                    After changing it to a public field  ungly  the test runner could discover the test    public TestContext TestContext    Very strange behaviour  but it was the cause of the issue in my case

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We had the same problem  We have a big VS 2015 solution with multiple C  projects in it and even more test projects    Resharper s test discovery worked just fine  but VS Test Explorer failed miserably   Turns out that the projects didn t have the same version of MsTest TestFramework and TestAdapter  and that sometimes they used NuGets and other times good old references  and that is not supported apparently  so much for such an expensive IDE    Removing all Microsoft VisualStudio Test  references and then adding   updating the two MSTest NuGets fixed the problem

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Update nunit framework to latest version  Download nunit test adapter from nuget Restart Visual studio

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Check out  if NUnit Test Adapter 2 3 is installed in VisualStudio   Tools gt Extensions and Updates   Make sure that correct processor architecture is chosen   Test gt Test Settings gt Default Processor Architecture

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In my case  the problem was  between the chair and keyboard    I had switched to a configuration in the Configuration Manager which did not include my unit test projects on build   Switching back to a configuration  e g  Debug  which includes all projects fixed the issue

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One reason for this problem is that your test class is not public  MSTest only discovers tests from public classes

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In Visual Studio 2015 Update 3  if you want to attach the tests in the test explorer then have to install the NUnit Test Adapter Download the adapter from Tools- Extension And Updates- Online tab you have to search for the adapter - Download  By restarting the Visual Studio you can see the change for the test framework

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In the VS Output pane  switched to the Test view   there was this error   Could not load file or assembly  XXX UnitTest  Version 9 4 0 0  Culture neutral  PublicKeyToken 14345dd3754e3918  or one of its dependencies  Strong name validation failed   Exception from HRESULT  0x8013141A   In the project settings for the test project  under the Signing tab  someone had checked  Sign the assembly   Unchecking that and building caused the tests to show up   A colleague also solved the same issue by adding keys from this post to the registry   https   blogs msdn microsoft com keithmg 2012 03 20 strong-name-validation-failed-exception-from-hresult-0x8013141a

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I was struggling with same problem for VSTest framework and my native unit tests   So  after doing all those things you mentioned before  I removed every occurence of     symbol in my solution s directory path  It actually works   I m leaving it here for googlers who will find this question in future

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It could be that your code is compiled with x64 therefore have to enable the Default Processor Architecture as X64   Test  gt  Test Settings  gt  Default Processor Architecture  gt  X64

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Popping in to share my solution  I was on Windows 10  Visual Studio 2015  NUnit 3 5  NUnit Test Adapter 3 6  via NuGet  not the VISX extension  and none of my tests were being discovered  My problem was that in the Tests project of my solution  somehow a shortcut to my  Documents  folder had been created within the project folder  I m guessing the test adapter was seeing the shortcut and getting hung up trying to figure out what to do with it  resulting in the failure to display unit tests

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To my surprise  clearing temp files located in the  TEMP  directory resolved the issue for me   Note  This path is generally at C  Users  yourusername  AppData Local Temp  As  Warren-P included  you can navigate to the temp folder by putting in  temp  in Start Menu  or launch  File Explorer  and enter  temp  in the address bar

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I would like to add one further reason tests may not be found  in my case it pertained C   unit tests that were not found   In my case tests were not found for a particular project because its output directory was not contained within the project directory  changing this ensured the tests were found

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The solution in my case was just to install the NUnit 3 Test Adapter extension to my Visual Studio 2015

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If you are working with multiple App or Web Config files  eg     Its likely you are using a Config that is RELEASE MODE and that will strip the Debug mode setting from the config      lt system web gt       lt compilation xdt Transform  RemoveAttributes debug     gt    Change the Config to one that doesn t remove DEBUG MODE

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I would just like to add that I found an entirely different solution to the ones above   I had declared my test class as below    TestClass  class ClassificationTests        unit tests     As soon as I added the public modifier to the class  it worked as expected

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I solved this problem by realizing that the Target Framework for my test project was different than the project under test  Yes  I caused this problem by changing the target framework from the default  Project Properties Application   but failed to this this for the test project  which was created several weeks later  The mismatch did not cause a compiler error  but it did result in a warning in the Error List window  Once I selected the option to display warnings  the solution was obvious

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If you re targetting  NET Standard or  NET Core  you need to use the NuGet package for NUnit Test Adapter and not the extension   It is recommended to install the adapter from NuGet if you are testing  NET Core or  NET Standard projects  The VSIX adapter does not  and will not  support  NET Core because VSIX packages cannot target multiple platforms   Source  NUnit GitHub Wiki   Also check the FAQ there   My tests aren t showing up in Visual Studio 2017   Are you using the NuGet package  Are you using version 3 8 0 or newer of the NuGet package  Do your tests target  NET Core or the full  NET Framework   see above  Have you added a Package Reference to Microsoft NET Test Sdk  Have you restarted Visual Studio  It is still a bit tempermental    Source  NUnit GitHub Wiki

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Ensure you have xunit runner visualstudio package in your test project packages config and also that was correctly restored   I know this was not the case of the original question however it could save time for someone like me

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After spending 2 days    none of the above worked for me  The only  solution  was  Go to project properties -  Build Tab  Then click Advanced button on the right bottom corner of the pane  Change  Debug Info   to  full  and click OK   Here are the screen shots

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Disable Windows Defender Service  Turning this off immediately caused all of my unit tests to show up in Test Explorer

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Deleting the file  AppData Local Microsoft VisualStudio 14 0 1033 SpecificFold  erCache xml solved the issue for me

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The only thing that worked for me was  Remove C  Users yourusername  AppData Local Temp  Other suggestions typically are valid  But for some reason  if VS does not pick up your changes and keeps barking in your output it cant discover tests  cleaning this dir can do the trick  And  yes  it may be just  some day  you startup and none of your solutions will work anymore  wheras  yesterday  everything worked fine

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I had the same pronlem but the folder   TEMP  VisualStudioTestExplorerExtensions  did not exist on my machine so as i read the posts i had the idea to create it and it works  The test explorer is now able to show all my tests  Thanks

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In my case  MSTest under VS 2015 was ignoring tests with test  i e  method  names that were longer than 174 characters  Shortening the name allowed the test to be visible  This was determined via guess-and-check by manipulating the test name

[unit-testing] Visual Studio 2015 or 2017 does not discover unit tests

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