Visual Studio unable to run .NET Core tests

Question

Using the latest version of Visual Studio, I'm unable to run any tests in the tests explorer. The error message in the Tests output window is:

Testhost process exited with error: It was not possible to find any compatible framework version
The framework 'Microsoft.AspNetCore.App', version '2.2.0' was not found.
  - The following frameworks were found:
      3.1.0 at [C:\Program Files (x86)\dotnet\shared\Microsoft.AspNetCore.App]
You can resolve the problem by installing the specified framework and/or SDK.
The specified framework can be found at:
  - https://aka.ms/dotnet-core-applaunch?framework=Microsoft.AspNetCore.App&framework_version=2.2.0&arch=x86&rid=win10-x86
. Please check the diagnostic logs for more information.
[17/12/2019 5:46:13.908 PM] ========== Run aborted: 0 tests run (0:00:00.2418036) ==========

So it's suggestion that I need to have .net core 2.2 installed but it cannot find it. It can only find 3.1.

Let's confirm that ....

C:\Users\justi>dotnet --info
.NET Core SDK (reflecting any global.json):
 Version:   3.1.100
 Commit:    cd82f021f4

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.18362
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.1.100\

Host (useful for support):
  Version: 3.1.0
  Commit:  65f04fb6db

.NET Core SDKs installed:
  2.1.604 [C:\Program Files\dotnet\sdk]
  2.1.700 [C:\Program Files\dotnet\sdk]
  2.1.701 [C:\Program Files\dotnet\sdk]
  2.1.801 [C:\Program Files\dotnet\sdk]
  2.1.802 [C:\Program Files\dotnet\sdk]
  2.2.100 [C:\Program Files\dotnet\sdk]
  2.2.200 [C:\Program Files\dotnet\sdk]
  2.2.201 [C:\Program Files\dotnet\sdk]
  2.2.202 [C:\Program Files\dotnet\sdk]
  2.2.204 [C:\Program Files\dotnet\sdk]
  2.2.206 [C:\Program Files\dotnet\sdk]
  2.2.300 [C:\Program Files\dotnet\sdk]
  2.2.301 [C:\Program Files\dotnet\sdk]
  2.2.401 [C:\Program Files\dotnet\sdk]
  2.2.402 [C:\Program Files\dotnet\sdk]
  3.1.100 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  <snip snip>
  Microsoft.AspNetCore.All 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  <snip snip>
  Microsoft.AspNetCore.App 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  <snip snip>
  Microsoft.AspNetCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  <snip snip>
  Microsoft.NETCore.App 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  <snip snip>
  Microsoft.NETCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

So it feels like I have 2.2.0 installed, as it's listed in the list of the many versions installed.

Edit

Notice this bit (emphasis mine):

• The following frameworks were found: 3.1.0 at [C:\Program Files (x86)\dotnet\shared\Microsoft.AspNetCore.App]

It looks like it's got 3.1.0 installed into .. x86 while the rest of the sdk's are installed under Program Files (x64 bit versions).

Why does it say this?

Edit 2:

• xUnit
• xUnit VS runner nuget is also 'installed'.
• Visual Studio 16.4.1

Answer 1

Change from CPU x86 to x64 … Test > Process architecture for anyCPU projects > x64

Answer 2

I too had this issue. The error displayed in the Tests Output.

Error message snippet:

Test data store opened in 0.153 sec. ---------- Starting test discovery for requested test run ---------- Microsoft.VisualStudio.TestPlatform.ObjectModel.TestPlatformException: Testhost process exited with error: It was not possible to find any compatible framework version The framework 'Microsoft.NETCore.App', version '2.1.0' was not found.

• The following frameworks were found: 3.1.9 at [C:\Program Files (x86)\dotnet\shared\Microsoft.NETCore.App] You can resolve the problem by installing the specified framework and/or SDK. The specified framework can be found at:
• https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=2.1.0&arch=x86&rid=win81-x86 . Please check the diagnostic logs for more information. at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyOperationManager.ThrowOnTestHostExited(Boolean testHostExited) at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyOperationManager.SetupChannel(IEnumerable`1 sources, String runSettings) at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyDiscoveryManager.DiscoverTests(DiscoveryCriteria discoveryCriteria, ITestDiscoveryEventsHandler2 eventHandler) ========== Test discovery aborted: 0 Tests found in 1.4 sec ========== Executing all tests in file: ConfigurationTests.cs ---------- Starting test run ---------- ========== Test run finished: 0 Tests run in 123.4 ms (0 Passed, 0 Failed, 0 Skipped) ==========

The issue occurred after installing .NET Core SDK 3.1.x. This change must of done something to Visual Studio Test settings.

Installations at (x86):

Installations at (x64):

I fixed it without any changes to the solution or project file. In my Test Explorer I chose the Processor Architecture for AnyCPU Projects. I changed it from x86 to x64.

Note: all of my .NET Core installations are x64. However, for some reason only 3.1.x existed in x86. My test project's Target framework is .NET Core 2.1, so to run the tests it needed to look in the x64 folder path.

How installations look from Add or Remove Programs: