Add dotnet.config to specify MTP for dotnet test

Author: Youssef1313

.github/copilot-instructions.md

@@ -47,18 +47,18 @@ In building and testing, never use `dotnet` without extension. Use `dotnet.sh` o
 
 Note that tests for a project can be executed without first building from the root.
 
-(4) To run just certain tests, it's important to include the filter after `--`, for example `dotnet.sh test tests/Aspire.Hosting.Testing.Tests/Aspire.Hosting.Testing.Tests.csproj --no-build --logger "console;verbosity=detailed" -- --filter "TestingBuilderHasAllPropertiesFromRealBuilder"`
+(4) To run just certain tests, it's important to include the filter after `--`, for example `dotnet.sh test tests/Aspire.Hosting.Testing.Tests/Aspire.Hosting.Testing.Tests.csproj --no-build --filter "TestingBuilderHasAllPropertiesFromRealBuilder"`
 
 ### Important: Excluding Quarantined Tests
 
 When running tests in automated environments (including Copilot agent), **always exclude quarantined tests** to avoid false negatives:
 
 ```bash
 # Correct - excludes quarantined tests (use this in automation)
-dotnet.sh test tests/Project.Tests/Project.Tests.csproj -- --filter-not-trait "quarantined=true"
+dotnet.sh test tests/Project.Tests/Project.Tests.csproj --filter-not-trait "quarantined=true"
 
 # For specific test filters, combine with quarantine exclusion
-dotnet.sh test tests/Project.Tests/Project.Tests.csproj -- --filter "TestName" --filter-not-trait "quarantined=true"
+dotnet.sh test tests/Project.Tests/Project.Tests.csproj --filter "TestName" --filter-not-trait "quarantined=true"
 ```
 
 Never run all tests without the quarantine filter in automated environments, as this will include flaky tests that are known to fail intermittently.

.github/workflows/run-tests.yml

@@ -255,7 +255,6 @@ jobs:
           -bl:${{ github.workspace }}/testresults/test.binlog
           --no-restore
           --no-build
-          --
           --ignore-exit-code 8
           --report-trx
           --hangdump --hangdump-timeout ${{ inputs.testHangTimeout }}

dotnet.config

@@ -0,0 +1,2 @@
+[dotnet.test.runner]
+name = "Microsoft.Testing.Platform"

tests/helix/send-to-helix-buildonhelixtests.targets

@@ -35,7 +35,7 @@
       <_TestBlameArguments Include="--crashdump-type Full" />
 
       <!-- Using `dotnet test` for the project directly here -->
-      <_TestRunCommandArguments Include="dotnet test -- --results-directory $(_HelixLogsPath) --report-trx --report-trx-filename TestResults.trx" />
+      <_TestRunCommandArguments Include="dotnet test --results-directory $(_HelixLogsPath) --report-trx --report-trx-filename TestResults.trx" />
       <_TestRunCommandArguments Include="@(_TestBlameArguments, ' ')" />
 
       <_TestRunCommandArguments Include="--filter-not-trait &quot;quarantined=true&quot;" />