Test discovery fails to discover tests and shows strange state in UI

[captainsafia]

Type: Bug

I've started observing that the test explorer seems to fail to discover tests when invoked lazily or on demand via the refresh tests button.

The UI also appears to show the directory name (?) instead of any actual tests:

Test discovery logs:

test-discovery-logs.txt

Environment information

VSCode version: 1.99.0
C# Extension: 2.72.27
Using OmniSharp: false

Dotnet Information

.NET SDK: Version: 9.0.200 Commit: 90e8b202f2 Workload version: 9.0.200-manifests.b4a8049f MSBuild version: 17.13.8+cbc39bea8

Runtime Environment:
OS Name: Mac OS X
OS Version: 15.4
OS Platform: Darwin
RID: osx-arm64
Base Path: /Users/captainsafia/git/aspire/acr-resource/.dotnet/sdk/9.0.200/

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.2
Architecture: arm64
Commit: 80aa709f5d

.NET SDKs installed:
9.0.200 [/Users/captainsafia/git/aspire/acr-resource/.dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 8.0.13 [/Users/captainsafia/git/aspire/acr-resource/.dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.2 [/Users/captainsafia/git/aspire/acr-resource/.dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 8.0.13 [/Users/captainsafia/git/aspire/acr-resource/.dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.2 [/Users/captainsafia/git/aspire/acr-resource/.dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
None

Environment variables:
DOTNET_ROOT [/Users/captainsafia/git/aspire/acr-resource/.dotnet]

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

[peterwald]

In the logs every test dll is reported with the message, "No test is available in /path/to/Tests.dll. Make sure that test discoverer & executors are registered and platform & framework version settings are appropriate and try again." This error message is only created by vstest.console.

In this case, the tests were building as MS Testing Platform (MTP) tests, which would not be able to be discovered by VsTest. There seem to have been a transitionary period where the tests were building as MTP but the project system was detecting them as VsTest tests.

This could be caused by opening the solution/project with an older version of the code (constructed for VsTest), rebuilding with VSCode open (which would build as MTP tests), after which discovery would fail for all of the test assemblies until VS Code was reloaded.

Given the above analysis, I am going to close this issue for now. Feel free to reopen if you feel this does not accurately represent what is happening.