Vfrdtyky

If you're using a NUnit3+ version, there is a new Test Adapter available.

Go to "Tools -> Extensions and Updates -> Online" and search for "NUnit3 Test Adapter" and then install.

My test assembly is 64-bit. From the menu bar at the top of visual studio 2012, I was able to select 'Test' -> 'Test Settings' -> 'Default Processor Architecture' -> 'X64'. After a 'Rebuild Solution' from the 'Build' menu, I was able to see all of my tests in test explorer. Hopefully this helps someone else in the future =D.

Check for NUnit versions mismatch. The currently available NUnit Test Adapter only works for NUnit version 2.6.4 and below.
To downgrade NUnit from version 3.x go to
Package Manager Console > update-package NUnit -version 2.6.4

http://jeremybytes.blogspot.co.ke/2015/11/review-of-unit-testing-makes-me-faster.html

In my situation the 'NUnit3 Test Adapter' has been disabled.
To re-enable it go to menu

Tools->Extensions and Updates...

On the left side select 'Installed'->'All'.

On the upper right corner search for 'nunit'.

If you have 'NUnit3 Test Adapter' installed, with the found item you can enable/disable it.

If you are using VS 2017 and .net core ,as said here, you should add references to the test framework NUnit 3.6.1, to the test runner NUnit3TestAdapter 3.8.0-alpha1 and to the test SDK Microsoft.NET.Test.Sdk 15.0.0.

This answer seems pretty basic but wasn't completely obvious to me at first. If you (re)build the solution it only builds the projects that are configured to build in the Build -> Configuration Manager

This was my issue, I must have inadvertently changed a build configuration settings or something that caused my test projects not to build (when they previously were). So the Test Explorer window was looking at dlls that were out of date. It became clear to me this was the case after doing a Clean and seeing most of my tests disappear and not come back after a rebuild...further inspection of bin folder showed that these projects weren't being built at all.

1. Tools


2. NuGet Package Manager


3. Manage NuGet Packages For Solution


4. Browse


5. NUnitTestAdapter.WithFramework


6. Ctrl+R,A to build/run tests

Using NUnitTestAdapter.WithFramework makes sure there are little/no inconsistencies across versions of NUnit and NUnit Adapter (i.e. "it just works")

I had a working setup (for NUnit2 and NUnit3 depending on the solution, and multiple versions of Visual Studio between 2012 and 2017), and it suddenly stopped working one day: no tests detected in any solution or version of VS.

In my case, it helped to delete %localappdata%TempVisualStudioTestExplorerExtensions. After a restart of VS, everything worked as before.

Check whether you have stated
[TestFixureSetUp]
and
[Test]

in the test class

sample:

namespace ClassLibrary1

{

public class SimpleCalculator

{

    public Calculator _calculator;

    [TestFixtureSetUp]

    public void initialize()

    {

        _calculator = new Calculator();



    }

    [Test]

    public void DivideTest()

    {

        int a = 10;

        int b = 2;

        int expectedValue = a/b;

        int actualValue = _calculator.Divide(a, b);

        Assert.AreEqual(expectedValue, actualValue, "Functionality not working properly!");

    }

}

}

One other cause to this problem is if you open a project from a mapped drive - Visual Studio handles such projects properly, but apparently Nunit doesn't support them.

Copying the project to a physical fixed the issue.

I also found that when I uninstalled nunit v3.2.1, the nunit framework reference for v3.2.1 was still in my project in solution explorer.
Solution Explorer > ProjectName > References

If you right click it will show the version. Remove this
Then Right click on References > Add Reference.

Search for the version 2.x version and add then rebuild solution.

That worked for me!

I experienced the problem mentioned by op

My case was that I was handed an old project and the tests were actually part of the system under test. I assume they were using the external test runner.

this task chain resolved the issue for me

• created a test project,


• moved the test files there


• added references so the test project would compile


• added the Nunit and Nunit adapter NuGet packages to the test project


• recompiled

i was able to successfully run the Nunit tests.

If you are using the TestCaseSource attribute, ensure the source exists and respects the documentation, otherwise your tests will not be discovered.

I had to uninstall then re-install the xunit.runner.visualstudio nuget package. I tried this after trying all the above suggestions, so may be it was a mixture of things.

I had a similar issue where the tests where not being discovered. I had the correct version of NUnit, versions matched up between NUnit and adapter, and the tests where tagged correctly. I was running VS 2017 Enterprise not as an administrator. After starting VS as administrator the tests appeared.

I started a new solution with a test project in it, and compared it against my original, problem project. The original, for some reason, had an app.config in it. I excluded that file from the project and saw my tests reappear in the test explorer.

I had this problem too but the cause was different. I'm using VS2017 with F# 4.0.

Firstly, the console in Visual Studio does not give you enough details why the tests could not be found; it will just fail to the load the DLL with the tests. So use NUnit3console.exe on the command line as this gives you more details.

In my case, it was because the test adapter was looking for a newer version of the F# Core DLL (4.4.1.0) (F# 4.1) whereas I'm still using 4.4.0.0 (F# 4.0). So I just added this to the app.config of the test project:-

  <dependentAssembly>

    <assemblyIdentity name="FSharp.Core" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />

    <bindingRedirect oldVersion="0.0.0.0-65535.65535.65535.65535" newVersion="4.4.0.0" />

  </dependentAssembly>

i.e. redirect to the earlier F# core.

I had the same problem, when suddenly any test didn't appeared on Test Explorer window.
I has the updated version of "NUnit3TestAdapter"

and after lots of searches and efforts,
I found that I need set the following values in project properties:
[In Solution Explorer window: right click on Project > Properties]
Under Build tab, set Platform=x64, and set Platform target=x86 or Any CPU
Build the project and all tests will be appear on Test Explorer window.

Important note:
I came to a solution after seeing the next msg in the output window:

"Test run will use DLL(s) built for framework Framework45 and platform X86. Following DLL(s) will not be part of run: AutomationTests.dll is built for Framework Framework45 and Platform X64."

I had some msbuild.exe processes that were hung. I don't know if that was my problem or not, but it took me a lot of trail and error with reinstalling various NUnit adaptors before I found the hung processes.

Make sure your tests are properly marked with the Test attribute. If all of the tests are marked with only the Explicit attribute, the TestAdapter doesn't recognize the fixture.