Tests not running in Test Explorer

Question

I am currently working on a solution that has currently 32 Unittests. I have been working with the resharper test runner - which works fine. All tests are running, all tests are showing the right test outcome.

However, the tests are not running when using the Visual Studio test explorer.

The Test Explorer is showing all unit tests, but once clicking on "Run All", all tests are getting greyed out and show no result of the test run:

• All test classes are public
• All test classes are having the [TestClass] attribute declared
• All test methods are using the [TestMethod] attribute
• Both the productivity code and the test projects are targeting .NET 3.5.
• I have already tried to clean build my solution, and / or delete all obj, bin, Debug and Release folders

I'd appreciate any hints which would explain this behaviour.

Answer 1

If your projects aren't all AnyCpu then you may also want to check that the following 2 settings match:

1. [Right click test project] -> properties -> Build -> Platform target - e.g. x64

2. [Main Menu] -> Test -> Test Settings -> Default Processor Architecture -> X64

I found that when these didn't match my test project would silently fail to run.

Answer 2

If you are using NUnit rather than MSTest then you will need the NUnit Test Adapter Extension for Visual Studio 2012/2013.

Answer 3

I had the same problem in VS 2017. In my case it solved by restarting VS.

Answer 4

I had to change my async test methods to return Task instead of void.

The tests were then active and runnable in Test Explorer.

Answer 5

Check what framework the tests are written against (e.g. nunit, xunit, VS test, etc.) and make sure you've got the correct test adapter/runner extension installed.

For me it was NUnit 3 Test Adapter that was missing and I confirmed the version number required by looking at the nunit.framework dependency version (select the .dll in the Dependencies tree in Solution Explorer and hit F4 to bring up the Properties window).

Answer 6

I found that in the project it was not referencing the Microsoft.VisualStudio.QualityTools.UnitTestFramework assembly. Instead, it was referencing Microsoft.VisualStudio.TestPlatform.TestFramework and Microsoft.VisualStudio.TestPlatform.TestFramework.Extensions. When I removed those two references and added the reference to the Microsoft.VisualStudio.QualityTools.UnitTestFramework assembly the tests that were previously marked with the blue exclamation point suddenly became active and started working.

Answer 7

TLDR: Update the testing packages, look into the output -> test console

I struggled with this for a day and a half. so here's what I did to solve it:

Symptoms

1. 5 Unit test projects, all discoverable in TestExplorer
2. 2 out of 5 executed properly
3. 3 stating not run at all
4. The problem started after a .net framework update

Investigation

Since all the packages were updated during the .net framework update, I started with the differences between the working and not working projects. The first clue was that all 3 projects were using: MSTest.TestAdapter and MSTest.TestFramework

Naturally I went to the -> Output console -> Test dropdown in VS 2019 and looked at the output. Nothing useful there.

Step one of the solution: Update the MSTest.TestAdapter and MSTest.TestFramework to version 2.0.0

Step two of the solution: Now the Output console -> Test dropdown output started showing one after the other, missing packages and wrong binding redirects

Step three of the solution: Manually add the missing packages. For me those were

1. System.Runtime.Extentions
2. System.Reflection
3. Maybe some more that I'm missing

Step 4 of the solution: Removed/Fixed the unnecessary binding redirects.

I hope this will help someone else.

Answer 8

Clean-Rebuild solution worked for me.

Answer 9

I had this issue and for me it was caused by having multiple Test Projects with different versions of :

• MSTest.TestAdapter
• MSTest.TestFramework

Consolidating the nuget packages for the projects so they were the same resolved the issue for me.

Answer 10

You can view the error-output of your test runner by opening the Output panel (view-->output) and choosing "tests" from the "Show output from" dropdown

---

Additionally, if you have Resharper installed you can open a test file and hover over the test-circle next to a test to get additional error info

Clicking that will bring you to a window with more detailed information. Alternatively, you can open that window by going to Extensions --> Reshaper --> Windows --> Unit Test Exploration Results

Answer 11

Install Nunit3TestAdapter Nuget has solved this problem

Answer 12

Had same issue after clean install of VS 2019. Tests are found but not run with "Unexpected error occurred". Fixed by setting up x64 instead of x86 which was selected by default.

Answer 13

In my case, it was because one test project in my solution had the MSTest.TestFramework and MSTest.TestAdapter nuget packages installed but the others did not. These packages were apparently not required to run tests until one project in the solution had them installed.

The issue was fixed by installing those packages on test projects missing them.

Answer 14

What fixed it for me was upgrading the MS.Test nuget packages

Answer 15

Setting Processor Architecture for AnyCPU Projects in Test Explorer fixed my issue! See screenshot above.

Answer 16

Have tried many options with Visual Studio 2019 Version 16.4.6 and Microsoft.VisualStudio.TestTools.UnitTesting, but for now the only way to run tests successfully was by invoking next command in console

dotnet test

Tests are discovered in Test Explorer but outcome is "Not Run".

Updating Visual Studio did not help.

Have resolved issue with "No test matches the given testcase filter FullyQualifiedName" by running updates to latest version for next packages:

Microsoft.NET.Test.Sdk
MSTest.TestAdapter
MSTest.TestFramework

Answer 17

Had the same symptoms, in my case it was the dotnet core SDK version that was the problem.

The projects was targeting 2.2, and was able to build using 3.0. After installing newest 2.2 SDK version they were able to run.

Answer 18

In my case I had an async void Method and I replaced with async Task ,so the test run as i expected :

    [TestMethod]
    public async  void SendTest(){}

replace with :

    [TestMethod]
    public async  Task SendTest(){}

Answer 19

I had same symptoms.

Please ensure you have the proper Visual Studio extension installed via Tools - Extensions and Updates. In my case, I had to install XUnit and Specflow from the Online option.

Then clean the solution and rebuild it.

If that still doesn't help, clear your temp directory (search for %temp% in the Start menu search and delete all contents in Temp)

And then finally try uninstalling Resharper which finally fixed my problem.

Answer 20

Here it was the test project was not marked to be built:

Build -> Configuration Manager... -> check build for your test project

Answer 21

I had different version of NUnit (3.11.0) and NunitTestAdapter (3.12.0) nuget packages. When I updated NUnit to 3.12.0, Visual Studio ran tests.

Answer 22

This issue is also observed when the test method being run throws a StackOverflowException, making the test runner abort the test run, resulting in the output 0 tests run.

To find the culprit and solve it put a break point at the start of both TestInitialize and TestMethod decorated methods, run the unit test in debug mode, proceed stepping over (F10) until the exception is thrown.

Answer 23

I am using XUnit and was missing the xunit.runner.visualstudio package. Installing it and my tests ran.

Answer 24

I had a slightly different scenario, but this is the top Google result so I'll answer my issue too. I could run the tests but only about half of them actually ran, with no error output.

Eventually I debugged and stepped through all the tests, and came upon a Stack Overflow Error when creating Test Instances of some models.

In the test instance methods, a child model created a parent and the parent created a child, which created an infinite loop. I removed the parent creation from the child, and now all my tests work!

Answer 25

I had a different solution to get my tests to run. My global packages folder didn't match what was in my .csproj This is what my .csproj looked like:

I had to change my Version to 16.5.0 which i found was installed in my global packages folder. Now my tests are able to run:

Answer 26

What works for me is to delete the bin folder, then rebuild the project.

Answer 27

For me solution was to change the Resharper Unit Testing settings "Default platform architecture" to "x64"

Answer 28

Since I got here with this kind of error I post my problem/solution:

Symptoms:

• Not all tests running, but they didn't depend per project, just some of them were executed.
• All executed ones were green.
• Tech stack: dotnet core / XUnit / FluentAssertions
• All tests detected and updated if it changed.
• By selection or running "Not runned tests" several times they could be executed.

Problem:

There was an error in the code that throw an exception inside another thread. All test assertions passed but it cancelled the test execution. I could see the error in the "Tests output" (NullException).

Answer 29

In my case it worked to update the MSTest nuget packages. Could reproduce this problem even on blank MSTest project and updating the packages worked.

Answer 30

There are already a lot of answers to this question, but I had a different scenario and resolution.

We moved functionality of a type being tested from one class to a new class, and as such created a new test class, with the old test class ending up being empty.

Original:

• Old test class
  • Test initialize method
  • Test methods

Broken:

• Old test class (initializer kept, class kept as placeholder for future)
  • Test initialize method (remains, by itself)
  • No test methods (the original test methods appear in test runner but don't exist in code so never execute)
• New test class
  • Test initialize method
  • Test methods

Fixed:

• Old test class (removed)
• New test class
  • Test initialize method
  • Test methods

Clean the project, close Visual Studio, delete the TestResults folder, then restart VS, then rebuild the project. (This alone might fix your problem, but for me didn't suffice until a deleted the old test class.)