From 31f61e68e77af6415280be948990114e7fe8a0ac Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Thu, 11 Jun 2026 03:36:36 -0700
Subject: [PATCH 01/10] Refactor build pipeline to separate test jobs

---
 diagnostics.yml         | 61 +++++++++++++++++++++++++++++++++++------
 eng/pipelines/build.yml | 23 ++++++++++++----
 2 files changed, 70 insertions(+), 14 deletions(-)

diff --git a/diagnostics.yml b/diagnostics.yml
index 343d9e85e5..2629d44813 100644
--- a/diagnostics.yml
+++ b/diagnostics.yml
@@ -52,7 +52,7 @@ extends:
   parameters:
     stages:
     - stage: build
-      displayName: Build and Test Diagnostics
+      displayName: Build Diagnostics
       jobs:
 
         ############################
@@ -79,10 +79,11 @@ extends:
           jobTemplate: ${{ variables.jobTemplate }}
           name: Windows
           osGroup: Windows_NT
-          buildOnly: ${{ parameters.buildOnly }}
+          buildOnly: true
           buildConfigs:
           - configuration: Debug
             architecture: x64
+            artifactUploadPath: bin/Windows_NT.x64.Debug
           - configuration: Release
             architecture: x64
             artifactUploadPath: bin
@@ -134,7 +135,7 @@ extends:
         parameters:
           jobTemplate: ${{ variables.jobTemplate }}
           osGroup: MacOS
-          buildOnly: ${{ parameters.buildOnly }}
+          buildOnly: true
           buildConfigs:
           - configuration: Release
             architecture: x64
@@ -142,6 +143,7 @@ extends:
           - ${{ if in(variables['Build.Reason'], 'PullRequest') }}:
             - configuration: Debug
               architecture: x64
+              artifactUploadPath: bin/osx.x64.Debug
 
       - template: /eng/pipelines/build.yml
         parameters:
@@ -212,13 +214,47 @@ extends:
               artifactUploadPath: bin/linux.arm64.Release
               artifactTargetPath: bin/linux-musl.arm64.Release
 
-      ############################
-      #                          #
-      #      Test only legs      #
-      #                          #
-      ############################
+    ############################
+    #                          #
+    #        Test stage        #
+    #                          #
+    ############################
+
+    - ${{ if ne(parameters.buildOnly, true) }}:
+      - stage: test
+        displayName: Test Diagnostics
+        dependsOn: build
+        jobs:
+
+        - template: /eng/pipelines/build.yml
+          parameters:
+            jobTemplate: ${{ variables.jobTemplate }}
+            name: Windows_Test
+            osGroup: Windows_NT
+            dependsOn: Windows
+            testOnly: true
+            buildConfigs:
+            - configuration: Debug
+              architecture: x64
+            - configuration: Release
+              architecture: x64
+            - configuration: Release
+              architecture: x86
+
+        - template: /eng/pipelines/build.yml
+          parameters:
+            jobTemplate: ${{ variables.jobTemplate }}
+            name: MacOS_Test
+            osGroup: MacOS
+            dependsOn: MacOS
+            testOnly: true
+            buildConfigs:
+            - configuration: Release
+              architecture: x64
+            - ${{ if in(variables['Build.Reason'], 'PullRequest') }}:
+              - configuration: Debug
+                architecture: x64
 
-      - ${{ if ne(parameters.buildOnly, true) }}:
         - template: /eng/pipelines/build.yml
           parameters:
             jobTemplate: ${{ variables.jobTemplate }}
@@ -267,9 +303,16 @@ extends:
         #         - configuration: Debug
         #           architecture: x64
 
+    ############################
+    #                          #
+    #      Package stage       #
+    #                          #
+    ############################
+
     - ${{ if and(ne(variables['System.TeamProject'], 'public'), notin(variables['Build.Reason'], 'PullRequest')) }}:
       - stage: package
         displayName: Package, Sign, and Generate BAR Manifests
+        dependsOn: build
         jobs:
         - template: /eng/common/templates-official/job/job.yml
           parameters:
diff --git a/eng/pipelines/build.yml b/eng/pipelines/build.yml
index 058d36f3f7..4d87be1e2e 100644
--- a/eng/pipelines/build.yml
+++ b/eng/pipelines/build.yml
@@ -113,7 +113,7 @@ jobs:
       ${{ if ne(parameters.strategy, '') }}:
         'error, we can no longer support the strategy feature in the new pipeline system. Please remove the strategy from the job template.': error
 
-      ${{ if ne(parameters.dependsOn, '') }}:
+      ${{ if and(ne(parameters.dependsOn, ''), ne(parameters.testOnly, true)) }}:
         dependsOn: ${{ parameters.dependsOn }}_${{ config.architecture }}_${{ config.configuration }}
 
       workspace:
@@ -133,6 +133,19 @@ jobs:
       - ${{ if ne(parameters.osGroup, 'Windows_NT') }}:
         - _buildScript: $(Build.SourcesDirectory)/build.sh
 
+      # Native artifact folder names used by the test-only legs.
+      # _downloadOSFolder: the folder name as published by the build leg.
+      # _localOSFolder: the folder name expected by the build script on the test machine.
+      - ${{ if eq(parameters.osGroup, 'Windows_NT') }}:
+        - _downloadOSFolder: Windows_NT
+        - _localOSFolder: Windows_NT
+      - ${{ elseif eq(parameters.osGroup, 'MacOS') }}:
+        - _downloadOSFolder: osx
+        - _localOSFolder: osx
+      - ${{ else }}:
+        - _downloadOSFolder: linux${{ parameters.osSuffix }}
+        - _localOSFolder: linux
+
       - ${{ if and(eq(parameters.testOnly, 'true'), eq(parameters.buildOnly, 'true')) }}:
         'error, testOnly and buildOnly cannot be true at the same time': error
 
@@ -157,8 +170,8 @@ jobs:
 
       steps:
       - ${{ if eq(parameters.testOnly, true) }}:
-        - ${{ if ne(parameters.osGroup, 'Linux') }}:
-          - 'error, testOnly is only supported on Linux': error
+        - ${{ if notIn(parameters.osGroup, 'Windows_NT', 'MacOS', 'Linux') }}:
+          - 'error, testOnly is only supported on Windows_NT, MacOS, and Linux': error
         - task: DownloadPipelineArtifact@2
           displayName: 'Download Build Artifacts'
           inputs:
@@ -168,8 +181,8 @@ jobs:
         - task: CopyFiles@2
           displayName: 'Binplace Downloaded Product'
           inputs:
-            sourceFolder: $(Build.ArtifactStagingDirectory)/__download__/Build_${{ parameters.dependsOn }}_${{ config.architecture }}_${{ config.configuration }}/bin/linux${{ parameters.osSuffix }}.${{ config.architecture }}.${{ config.configuration }}
-            targetFolder: '$(Build.SourcesDirectory)/artifacts/bin/linux.${{ config.architecture }}.${{ config.configuration }}'
+            sourceFolder: $(Build.ArtifactStagingDirectory)/__download__/Build_${{ parameters.dependsOn }}_${{ config.architecture }}_${{ config.configuration }}/bin/$(_downloadOSFolder).${{ config.architecture }}.${{ config.configuration }}
+            targetFolder: '$(Build.SourcesDirectory)/artifacts/bin/$(_localOSFolder).${{ config.architecture }}.${{ config.configuration }}'
 
       - script: $(_buildScript)
           -ci

From b5ff03d6b0d8524e2060d1f3ca7e8177084a046f Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Fri, 26 Jun 2026 13:06:53 -0700
Subject: [PATCH 02/10] Split CI build/test outputs and move tests to net10

- Publish full test artifacts from build-only legs and consume them in test-only legs with -skipmanaged\n- Gate test artifact publish on buildOnly to avoid duplicate or invalid publish work\n- Ensure test runtimes/sdk install in skipmanaged test legs via explicit InstallRuntimes build step\n- Keep tools on net8.0 while moving unit tests to net10.0\n- Remove global.json tools.runtimes dependency and fix net10 analyzer warnings in EventLogsPipelineUnitTests\n\nCo-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 Directory.Build.props                         | 10 +++-
 diagnostics.yml                               |  4 ++
 eng/build.ps1                                 | 25 +++++++++
 eng/build.sh                                  | 27 ++++++++++
 eng/pipelines/build.yml                       | 54 +++++++++++--------
 global.json                                   | 10 +---
 .../DbgShim.UnitTests.csproj                  |  2 +-
 ...Diagnostics.DebugServices.UnitTests.csproj |  2 +-
 .../EventLogsPipelineUnitTests.cs             | 12 ++---
 .../Microsoft.FileFormats.UnitTests.csproj    |  2 +-
 .../Microsoft.SymbolStore.UnitTests.csproj    |  2 +-
 src/tests/SOS.UnitTests/SOS.UnitTests.csproj  |  2 +-
 .../DotnetCounters.UnitTests.csproj           |  2 +-
 .../dotnet-trace/DotnetTrace.UnitTests.csproj |  2 +-
 14 files changed, 112 insertions(+), 44 deletions(-)

diff --git a/Directory.Build.props b/Directory.Build.props
index 9fe222dc98..e6a583c5c6 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -69,10 +69,18 @@
      -->
     <NetCoreAppMinVersion>8.0</NetCoreAppMinVersion>
     <NetCoreAppMinTargetFramework>net$(NetCoreAppMinVersion)</NetCoreAppMinTargetFramework>
+    <!--
+        The TFM our unit tests run as. The tools must remain on $(NetCoreAppMinTargetFramework),
+        but the tests run on the SDK version from global.json, so they can target a newer TFM.
+        Keeping the tests on the live SDK's TFM means the SDK already ships the matching runtime,
+        so no extra shared runtime needs to be installed via global.json's tools.runtimes node.
+     -->
+    <NetCoreAppTestVersion>10.0</NetCoreAppTestVersion>
+    <NetCoreAppTestTargetFramework>net$(NetCoreAppTestVersion)</NetCoreAppTestTargetFramework>
     <!-- This is the list of TFMs we build our debuggees and tracees as. -->
     <SupportedSubProcessTargetFrameworks>net8.0;net9.0;net10.0;net11.0</SupportedSubProcessTargetFrameworks>
     <!-- This is the list of TFMs we build our unit tests as. -->
-    <SupportedXUnitTestTargetFrameworks>net8.0</SupportedXUnitTestTargetFrameworks>
+    <SupportedXUnitTestTargetFrameworks>$(NetCoreAppTestTargetFramework)</SupportedXUnitTestTargetFrameworks>
   </PropertyGroup>
 
 </Project>
diff --git a/diagnostics.yml b/diagnostics.yml
index 2629d44813..ded5f372e1 100644
--- a/diagnostics.yml
+++ b/diagnostics.yml
@@ -80,6 +80,7 @@ extends:
           name: Windows
           osGroup: Windows_NT
           buildOnly: true
+          publishTestArtifacts: true
           buildConfigs:
           - configuration: Debug
             architecture: x64
@@ -102,6 +103,7 @@ extends:
           container: linux_x64
           crossBuild: true
           buildOnly: true
+          publishTestArtifacts: true
           buildConfigs:
           - configuration: Release
             architecture: x64
@@ -120,6 +122,7 @@ extends:
           container: linux_musl_x64
           crossBuild: true
           buildOnly: true
+          publishTestArtifacts: true
           buildConfigs:
           - configuration: Release
             architecture: x64
@@ -136,6 +139,7 @@ extends:
           jobTemplate: ${{ variables.jobTemplate }}
           osGroup: MacOS
           buildOnly: true
+          publishTestArtifacts: true
           buildConfigs:
           - configuration: Release
             architecture: x64
diff --git a/eng/build.ps1 b/eng/build.ps1
index 975097c9a6..0dceb53c6a 100644
--- a/eng/build.ps1
+++ b/eng/build.ps1
@@ -124,8 +124,33 @@ if ($test) {
             $testFilterArg = "/p:TestRunnerAdditionalArguments=\`"-class $classfilter\`""
         }
 
+        # When the managed build was skipped (e.g. the test-only CI legs that download prebuilt
+        # product binaries), the test SDK and runtimes that are normally installed during the
+        # managed build (InstallRuntimes.proj, InstallTestRuntimes AfterTargets=Build) were never
+        # installed on this machine. Build just that project here so the runtimes are present
+        # before the tests run. This is ordered ahead of -test, unlike relying on the parallel
+        # test traversal, and avoids rebuilding the downloaded product.
+        if ($skipmanaged) {
+            & "$engroot\common\build.ps1" `
+              -restore `
+              -build `
+              -projects "$engroot\InstallRuntimes.proj" `
+              -configuration $configuration `
+              -verbosity $verbosity `
+              -ci:$ci `
+              /bl:$logdir\InstallTestRuntimes.binlog `
+              /p:TargetOS=$os `
+              /p:TargetArch=$architecture `
+              /p:LiveRuntimeDir="$liveRuntimeDir"
+
+            if ($lastExitCode -ne 0) {
+                exit $lastExitCode
+            }
+        }
+
         & "$engroot\common\build.ps1" `
           -test `
+          -restore:$skipmanaged `
           -configuration $configuration `
           -verbosity $verbosity `
           -ci:$ci `
diff --git a/eng/build.sh b/eng/build.sh
index 1320b0a723..d1a8599b57 100755
--- a/eng/build.sh
+++ b/eng/build.sh
@@ -353,9 +353,36 @@ if [[ "$__Test" == 1 ]]; then
           __TestFilterArg="/p:TestRunnerAdditionalArguments=\"$__TestFilter\""
       fi
 
+      # When the managed build was skipped (e.g. the test-only CI legs that download prebuilt
+      # product binaries), the test SDK and runtimes that are normally installed during the
+      # managed build (InstallRuntimes.proj, InstallTestRuntimes AfterTargets=Build) were never
+      # installed on this machine. Build just that project here so the runtimes are present
+      # before the tests run. This is ordered ahead of --test, unlike relying on the parallel
+      # test traversal, and avoids rebuilding the downloaded product.
+      __TestRestoreArg=
+      if [[ "$__ManagedBuild" == 0 ]]; then
+          __TestRestoreArg=--restore
+
+          "$__RepoRootDir/eng/common/build.sh" \
+            --restore \
+            --build \
+            --projects "$__RepoRootDir/eng/InstallRuntimes.proj" \
+            --configuration "$__BuildType" \
+            /bl:"$__LogsDir"/InstallTestRuntimes.binlog \
+            /p:TargetArch="$__TargetArch" \
+            /p:TargetRid="$__TargetRid" \
+            /p:LiveRuntimeDir="$__LiveRuntimeDir" \
+            $__CommonMSBuildArgs
+
+          if [ "$?" != 0 ]; then
+              exit 1
+          fi
+      fi
+
       # __CommonMSBuildArgs contains TargetOS property
       "$__RepoRootDir/eng/common/build.sh" \
         --test \
+        $__TestRestoreArg \
         --configuration "$__BuildType" \
         /bl:"$__LogsDir"/Test.binlog \
         /p:TargetArch="$__TargetArch" \
diff --git a/eng/pipelines/build.yml b/eng/pipelines/build.yml
index 4d87be1e2e..0b90f515f8 100644
--- a/eng/pipelines/build.yml
+++ b/eng/pipelines/build.yml
@@ -60,6 +60,12 @@ parameters:
   type: boolean
   default: false
 
+  # Optional: publish the full build outputs (managed + native + debuggees) as a
+  # 'TestArtifacts_<phase>' artifact so the matching test-only legs can run without rebuilding.
+- name: publishTestArtifacts
+  type: boolean
+  default: false
+
 # Optional: architecture cross build if true
 - name: crossBuild
   type: boolean
@@ -133,24 +139,11 @@ jobs:
       - ${{ if ne(parameters.osGroup, 'Windows_NT') }}:
         - _buildScript: $(Build.SourcesDirectory)/build.sh
 
-      # Native artifact folder names used by the test-only legs.
-      # _downloadOSFolder: the folder name as published by the build leg.
-      # _localOSFolder: the folder name expected by the build script on the test machine.
-      - ${{ if eq(parameters.osGroup, 'Windows_NT') }}:
-        - _downloadOSFolder: Windows_NT
-        - _localOSFolder: Windows_NT
-      - ${{ elseif eq(parameters.osGroup, 'MacOS') }}:
-        - _downloadOSFolder: osx
-        - _localOSFolder: osx
-      - ${{ else }}:
-        - _downloadOSFolder: linux${{ parameters.osSuffix }}
-        - _localOSFolder: linux
-
       - ${{ if and(eq(parameters.testOnly, 'true'), eq(parameters.buildOnly, 'true')) }}:
         'error, testOnly and buildOnly cannot be true at the same time': error
 
       - ${{ if eq(parameters.testOnly, 'true') }}:
-        - _TestArgs: '-test -skipnative'
+        - _TestArgs: '-test -skipnative -skipmanaged'
 
       - ${{ if eq(parameters.buildOnly, 'true') }}:
         - _TestArgs: ''
@@ -172,17 +165,16 @@ jobs:
       - ${{ if eq(parameters.testOnly, true) }}:
         - ${{ if notIn(parameters.osGroup, 'Windows_NT', 'MacOS', 'Linux') }}:
           - 'error, testOnly is only supported on Windows_NT, MacOS, and Linux': error
+        # The matching build leg published its full outputs (managed assemblies, native
+        # binaries, and debuggees) as TestArtifacts_<phase>. Restore them into the repo
+        # artifacts directory so the test run can skip both the native and managed builds
+        # (-skipnative -skipmanaged) and only execute the tests.
         - task: DownloadPipelineArtifact@2
           displayName: 'Download Build Artifacts'
           inputs:
-            targetPath: '$(Build.ArtifactStagingDirectory)/__download__'
-            itemPattern: Build_${{ parameters.dependsOn }}_${{ config.architecture }}_${{ config.configuration }}/bin/**
+            artifact: TestArtifacts_${{ parameters.dependsOn }}_${{ config.architecture }}_${{ config.configuration }}
+            targetPath: '$(Build.SourcesDirectory)/artifacts'
             checkDownloadedFiles: true
-        - task: CopyFiles@2
-          displayName: 'Binplace Downloaded Product'
-          inputs:
-            sourceFolder: $(Build.ArtifactStagingDirectory)/__download__/Build_${{ parameters.dependsOn }}_${{ config.architecture }}_${{ config.configuration }}/bin/$(_downloadOSFolder).${{ config.architecture }}.${{ config.configuration }}
-            targetFolder: '$(Build.SourcesDirectory)/artifacts/bin/$(_localOSFolder).${{ config.architecture }}.${{ config.configuration }}'
 
       - script: $(_buildScript)
           -ci
@@ -215,6 +207,26 @@ jobs:
               targetPath: '$(Build.ArtifactStagingDirectory)/artifacts'
               artifactName: Build_$(_PhaseName)
 
+      # Publish the full build outputs for the matching test-only legs to consume. This lets the
+      # test legs run with -skipnative -skipmanaged instead of rebuilding the product themselves.
+      # Only valid on build-only legs (publishTestArtifacts without buildOnly is a configuration error).
+      - ${{ if and(eq(parameters.publishTestArtifacts, true), eq(parameters.buildOnly, true)) }}:
+        - task: CopyFiles@2
+          displayName: Gather test artifacts for publish
+          inputs:
+            SourceFolder: '$(Build.SourcesDirectory)/artifacts'
+            Contents: |
+              bin/**
+              test/**
+            TargetFolder: $(Build.ArtifactStagingDirectory)/testartifacts
+
+        - template: /eng/pipelines/publish-pipeline-artifact-shim.yml@self
+          parameters:
+            displayName: Publish Test Artifacts
+            inputs:
+              targetPath: '$(Build.ArtifactStagingDirectory)/testartifacts'
+              artifactName: TestArtifacts_$(_PhaseName)
+
       - ${{ if ne(parameters.buildOnly, 'true') }}:
         # Publish test results to Azure Pipelines
         - task: PublishTestResults@2
diff --git a/global.json b/global.json
index 75792e25d1..c212145c75 100644
--- a/global.json
+++ b/global.json
@@ -5,15 +5,7 @@
     "rollForward": "major"
   },
   "tools": {
-    "dotnet": "10.0.108",
-    "runtimes": {
-      "dotnet": [
-        "$(MicrosoftNETCoreApp80Version)"
-      ],
-      "dotnet/x86": [
-        "$(MicrosoftNETCoreApp80Version)"
-      ]
-    }
+    "dotnet": "10.0.108"
   },
   "msbuild-sdks": {
     "Microsoft.Build.NoTargets": "3.7.0",
diff --git a/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj b/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj
index c931e79852..3b9c84c185 100644
--- a/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj
+++ b/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <DbgShimConfigFileName>$(OutputPath)$(TargetFramework)\Debugger.Tests.Common.txt</DbgShimConfigFileName>
     <TestAssetsVersion>1.0.351101</TestAssetsVersion>
diff --git a/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj b/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj
index 9a4014149c..e71b2f7d7f 100644
--- a/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj
+++ b/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <DebugServicesConfigFileName>$(OutputPath)$(TargetFramework)\Debugger.Tests.Common.txt</DebugServicesConfigFileName>
     <TestAssetsVersion>1.0.351101</TestAssetsVersion>
     <!-- Controls the test asset package restore and the tests that use them -->
diff --git a/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs b/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs
index c8ed1e4f24..1b1d00e0e8 100644
--- a/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs
+++ b/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs
@@ -62,7 +62,7 @@ public async Task TestLogsAllCategoriesAllLevels(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -84,7 +84,7 @@ public async Task TestLogsAllCategoriesDefaultLevel(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -116,7 +116,7 @@ public async Task TestLogsAllCategoriesDefaultLevelFallback(TestConfiguration co
             ValidateLoggerRemoteCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -157,7 +157,7 @@ public async Task TestLogsUseAppFilters(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -182,7 +182,7 @@ public async Task TestLogsUseAppFiltersAndFilterSpecs(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -213,7 +213,7 @@ public async Task TestLogsWildcardCategory(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         private async Task<Stream> GetLogsAsync(TestConfiguration config, Action<EventLogsPipelineSettings> settingsCallback = null)
diff --git a/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj b/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj
index 808617aa05..513ca6baa5 100644
--- a/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj
+++ b/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <NoWarn>;1591;1701</NoWarn>
   </PropertyGroup>
 
diff --git a/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj b/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj
index e2dc9e42a7..3805aa1334 100644
--- a/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj
+++ b/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <NoWarn>;1591;1701</NoWarn>
   </PropertyGroup>
 
diff --git a/src/tests/SOS.UnitTests/SOS.UnitTests.csproj b/src/tests/SOS.UnitTests/SOS.UnitTests.csproj
index d2f3b4cbb7..df9a23e046 100644
--- a/src/tests/SOS.UnitTests/SOS.UnitTests.csproj
+++ b/src/tests/SOS.UnitTests/SOS.UnitTests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <IsPackable>false</IsPackable>
     <NoWarn>;1591;1701</NoWarn>
     <DefineConstants>$(DefineConstants);CORE_CLR</DefineConstants>
diff --git a/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj b/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj
index aa872e9b45..6472bcfb65 100644
--- a/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj
+++ b/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj b/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj
index 9d70543023..056dd23295 100644
--- a/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj
+++ b/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

From 3b05a959acc099512cf2a81df0e8d2da3620d037 Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Fri, 26 Jun 2026 18:57:06 -0700
Subject: [PATCH 03/10] Keep tests on net8

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 Directory.Build.props                                | 10 +---------
 global.json                                          | 10 +++++++++-
 src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj |  2 +-
 ...rosoft.Diagnostics.DebugServices.UnitTests.csproj |  2 +-
 .../EventLogsPipelineUnitTests.cs                    | 12 ++++++------
 .../Microsoft.FileFormats.UnitTests.csproj           |  2 +-
 .../Microsoft.SymbolStore.UnitTests.csproj           |  2 +-
 src/tests/SOS.UnitTests/SOS.UnitTests.csproj         |  2 +-
 .../dotnet-counters/DotnetCounters.UnitTests.csproj  |  2 +-
 src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj  |  2 +-
 10 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/Directory.Build.props b/Directory.Build.props
index e6a583c5c6..9fe222dc98 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -69,18 +69,10 @@
      -->
     <NetCoreAppMinVersion>8.0</NetCoreAppMinVersion>
     <NetCoreAppMinTargetFramework>net$(NetCoreAppMinVersion)</NetCoreAppMinTargetFramework>
-    <!--
-        The TFM our unit tests run as. The tools must remain on $(NetCoreAppMinTargetFramework),
-        but the tests run on the SDK version from global.json, so they can target a newer TFM.
-        Keeping the tests on the live SDK's TFM means the SDK already ships the matching runtime,
-        so no extra shared runtime needs to be installed via global.json's tools.runtimes node.
-     -->
-    <NetCoreAppTestVersion>10.0</NetCoreAppTestVersion>
-    <NetCoreAppTestTargetFramework>net$(NetCoreAppTestVersion)</NetCoreAppTestTargetFramework>
     <!-- This is the list of TFMs we build our debuggees and tracees as. -->
     <SupportedSubProcessTargetFrameworks>net8.0;net9.0;net10.0;net11.0</SupportedSubProcessTargetFrameworks>
     <!-- This is the list of TFMs we build our unit tests as. -->
-    <SupportedXUnitTestTargetFrameworks>$(NetCoreAppTestTargetFramework)</SupportedXUnitTestTargetFrameworks>
+    <SupportedXUnitTestTargetFrameworks>net8.0</SupportedXUnitTestTargetFrameworks>
   </PropertyGroup>
 
 </Project>
diff --git a/global.json b/global.json
index c212145c75..75792e25d1 100644
--- a/global.json
+++ b/global.json
@@ -5,7 +5,15 @@
     "rollForward": "major"
   },
   "tools": {
-    "dotnet": "10.0.108"
+    "dotnet": "10.0.108",
+    "runtimes": {
+      "dotnet": [
+        "$(MicrosoftNETCoreApp80Version)"
+      ],
+      "dotnet/x86": [
+        "$(MicrosoftNETCoreApp80Version)"
+      ]
+    }
   },
   "msbuild-sdks": {
     "Microsoft.Build.NoTargets": "3.7.0",
diff --git a/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj b/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj
index 3b9c84c185..c931e79852 100644
--- a/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj
+++ b/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <DbgShimConfigFileName>$(OutputPath)$(TargetFramework)\Debugger.Tests.Common.txt</DbgShimConfigFileName>
     <TestAssetsVersion>1.0.351101</TestAssetsVersion>
diff --git a/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj b/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj
index e71b2f7d7f..9a4014149c 100644
--- a/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj
+++ b/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
     <DebugServicesConfigFileName>$(OutputPath)$(TargetFramework)\Debugger.Tests.Common.txt</DebugServicesConfigFileName>
     <TestAssetsVersion>1.0.351101</TestAssetsVersion>
     <!-- Controls the test asset package restore and the tests that use them -->
diff --git a/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs b/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs
index 1b1d00e0e8..c8ed1e4f24 100644
--- a/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs
+++ b/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs
@@ -62,7 +62,7 @@ public async Task TestLogsAllCategoriesAllLevels(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
+            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -84,7 +84,7 @@ public async Task TestLogsAllCategoriesDefaultLevel(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
+            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -116,7 +116,7 @@ public async Task TestLogsAllCategoriesDefaultLevelFallback(TestConfiguration co
             ValidateLoggerRemoteCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
+            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -157,7 +157,7 @@ public async Task TestLogsUseAppFilters(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
+            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -182,7 +182,7 @@ public async Task TestLogsUseAppFiltersAndFilterSpecs(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
+            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -213,7 +213,7 @@ public async Task TestLogsWildcardCategory(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
+            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
         }
 
         private async Task<Stream> GetLogsAsync(TestConfiguration config, Action<EventLogsPipelineSettings> settingsCallback = null)
diff --git a/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj b/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj
index 513ca6baa5..808617aa05 100644
--- a/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj
+++ b/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
     <NoWarn>;1591;1701</NoWarn>
   </PropertyGroup>
 
diff --git a/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj b/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj
index 3805aa1334..e2dc9e42a7 100644
--- a/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj
+++ b/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
     <NoWarn>;1591;1701</NoWarn>
   </PropertyGroup>
 
diff --git a/src/tests/SOS.UnitTests/SOS.UnitTests.csproj b/src/tests/SOS.UnitTests/SOS.UnitTests.csproj
index df9a23e046..d2f3b4cbb7 100644
--- a/src/tests/SOS.UnitTests/SOS.UnitTests.csproj
+++ b/src/tests/SOS.UnitTests/SOS.UnitTests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
     <IsPackable>false</IsPackable>
     <NoWarn>;1591;1701</NoWarn>
     <DefineConstants>$(DefineConstants);CORE_CLR</DefineConstants>
diff --git a/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj b/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj
index 6472bcfb65..aa872e9b45 100644
--- a/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj
+++ b/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj b/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj
index 056dd23295..9d70543023 100644
--- a/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj
+++ b/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

From 7895776ee60a1a8f9f4afa257e191a97ea674e16 Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Sun, 28 Jun 2026 22:56:02 -0700
Subject: [PATCH 04/10] Skip debuggee/runtime rebuild on test legs; bundle
 dotnet-test

Build legs already compile all debuggee TFMs and install test runtimes; test
legs were redundantly rebuilding both. Publish artifacts/dotnet-test in the
TestArtifacts package so test legs download SDK+runtimes and skip InstallRuntimes
and BuildDebuggees via SkipTestArtifactsBuild. buildOnly still builds everything.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 eng/build.ps1           | 27 +++++----------------------
 eng/build.sh            | 26 ++++++--------------------
 eng/pipelines/build.yml |  1 +
 src/tests/dirs.proj     |  8 +++++---
 4 files changed, 17 insertions(+), 45 deletions(-)

diff --git a/eng/build.ps1 b/eng/build.ps1
index 0dceb53c6a..632edd263c 100644
--- a/eng/build.ps1
+++ b/eng/build.ps1
@@ -125,28 +125,10 @@ if ($test) {
         }
 
         # When the managed build was skipped (e.g. the test-only CI legs that download prebuilt
-        # product binaries), the test SDK and runtimes that are normally installed during the
-        # managed build (InstallRuntimes.proj, InstallTestRuntimes AfterTargets=Build) were never
-        # installed on this machine. Build just that project here so the runtimes are present
-        # before the tests run. This is ordered ahead of -test, unlike relying on the parallel
-        # test traversal, and avoids rebuilding the downloaded product.
-        if ($skipmanaged) {
-            & "$engroot\common\build.ps1" `
-              -restore `
-              -build `
-              -projects "$engroot\InstallRuntimes.proj" `
-              -configuration $configuration `
-              -verbosity $verbosity `
-              -ci:$ci `
-              /bl:$logdir\InstallTestRuntimes.binlog `
-              /p:TargetOS=$os `
-              /p:TargetArch=$architecture `
-              /p:LiveRuntimeDir="$liveRuntimeDir"
-
-            if ($lastExitCode -ne 0) {
-                exit $lastExitCode
-            }
-        }
+        # product binaries), the test SDK, runtimes, and debuggees that are normally produced by
+        # the managed build (InstallRuntimes.proj + BuildDebuggees in src/tests/dirs.proj) were
+        # downloaded as part of TestArtifacts. Skip rebuilding them so this leg only runs tests.
+        $skipTestArtifactsBuild = if ($skipmanaged) { 'true' } else { 'false' }
 
         & "$engroot\common\build.ps1" `
           -test `
@@ -158,6 +140,7 @@ if ($test) {
           /p:TargetOS=$os `
           /p:TargetArch=$architecture `
           /p:TestArchitectures=$architecture `
+          /p:SkipTestArtifactsBuild=$skipTestArtifactsBuild `
           /p:DotnetRuntimeVersion="$dotnetruntimeversion" `
           /p:DotnetRuntimeDownloadVersion="$dotnetruntimedownloadversion" `
           /p:RuntimeSourceFeed="$runtimesourcefeed" `
diff --git a/eng/build.sh b/eng/build.sh
index d1a8599b57..b6053294ae 100755
--- a/eng/build.sh
+++ b/eng/build.sh
@@ -354,29 +354,14 @@ if [[ "$__Test" == 1 ]]; then
       fi
 
       # When the managed build was skipped (e.g. the test-only CI legs that download prebuilt
-      # product binaries), the test SDK and runtimes that are normally installed during the
-      # managed build (InstallRuntimes.proj, InstallTestRuntimes AfterTargets=Build) were never
-      # installed on this machine. Build just that project here so the runtimes are present
-      # before the tests run. This is ordered ahead of --test, unlike relying on the parallel
-      # test traversal, and avoids rebuilding the downloaded product.
+      # product binaries), the test SDK, runtimes, and debuggees that are normally produced by
+      # the managed build (InstallRuntimes.proj + BuildDebuggees in src/tests/dirs.proj) were
+      # downloaded as part of TestArtifacts. Skip rebuilding them so this leg only runs tests.
       __TestRestoreArg=
+      __SkipTestArtifactsBuild=false
       if [[ "$__ManagedBuild" == 0 ]]; then
           __TestRestoreArg=--restore
-
-          "$__RepoRootDir/eng/common/build.sh" \
-            --restore \
-            --build \
-            --projects "$__RepoRootDir/eng/InstallRuntimes.proj" \
-            --configuration "$__BuildType" \
-            /bl:"$__LogsDir"/InstallTestRuntimes.binlog \
-            /p:TargetArch="$__TargetArch" \
-            /p:TargetRid="$__TargetRid" \
-            /p:LiveRuntimeDir="$__LiveRuntimeDir" \
-            $__CommonMSBuildArgs
-
-          if [ "$?" != 0 ]; then
-              exit 1
-          fi
+          __SkipTestArtifactsBuild=true
       fi
 
       # __CommonMSBuildArgs contains TargetOS property
@@ -387,6 +372,7 @@ if [[ "$__Test" == 1 ]]; then
         /bl:"$__LogsDir"/Test.binlog \
         /p:TargetArch="$__TargetArch" \
         /p:TargetRid="$__TargetRid" \
+        /p:SkipTestArtifactsBuild="$__SkipTestArtifactsBuild" \
         /p:DotnetRuntimeVersion="$__DotnetRuntimeVersion" \
         /p:DotnetRuntimeDownloadVersion="$__DotnetRuntimeDownloadVersion" \
         /p:RuntimeSourceFeed="$__RuntimeSourceFeed" \
diff --git a/eng/pipelines/build.yml b/eng/pipelines/build.yml
index 0b90f515f8..7906f41137 100644
--- a/eng/pipelines/build.yml
+++ b/eng/pipelines/build.yml
@@ -218,6 +218,7 @@ jobs:
             Contents: |
               bin/**
               test/**
+              dotnet-test/**
             TargetFolder: $(Build.ArtifactStagingDirectory)/testartifacts
 
         - template: /eng/pipelines/publish-pipeline-artifact-shim.yml@self
diff --git a/src/tests/dirs.proj b/src/tests/dirs.proj
index c57f908ddc..aef9406cb7 100644
--- a/src/tests/dirs.proj
+++ b/src/tests/dirs.proj
@@ -16,8 +16,10 @@
 
     <!-- Install test runtimes (SDK, shared frameworks) into artifacts/dotnet-test/.
          Using ProjectReference ensures the install runs exactly once via MSBuild's
-         result cache, even when multiple test projects depend on it. -->
-    <ProjectReference Include="$(RepositoryEngineeringDir)InstallRuntimes.proj" ReferenceOutputAssembly="false" SkipGetTargetFrameworkProperties="true" />
+         result cache, even when multiple test projects depend on it.
+         Skipped on test-only legs ($(SkipTestArtifactsBuild)) which download a
+         prebuilt artifacts/dotnet-test directory instead of installing locally. -->
+    <ProjectReference Include="$(RepositoryEngineeringDir)InstallRuntimes.proj" ReferenceOutputAssembly="false" SkipGetTargetFrameworkProperties="true" Condition="'$(SkipTestArtifactsBuild)' != 'true'" />
   </ItemGroup>
 
   <!--
@@ -39,7 +41,7 @@
 
   <Target Name="BuildDebuggees"
           AfterTargets="Build"
-          Condition="'$(SkipTests)' != 'true'">
+          Condition="'$(SkipTests)' != 'true' and '$(SkipTestArtifactsBuild)' != 'true'">
     <!-- Remove stale SDKs from the build dotnet dir so the repo root global.json
          (rollForward:major) resolves to the correct test SDK.  InstallTestRuntimes
          only installs $(MicrosoftNETSdkVersion); older SDKs are leftovers. -->

From a5ed15679f118240014837dc5b3b2c8374616067 Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Sun, 28 Jun 2026 23:51:27 -0700
Subject: [PATCH 05/10] Install runtimes fresh on test legs instead of bundling
 dotnet-test

CopyFiles/DownloadPipelineArtifact dropped exec bits on the bundled dotnet-test host, breaking every test that launches a debuggee. Install runtimes locally on test legs (cheap, correct perms) and only skip the expensive debuggee rebuild via SkipTestArtifactsBuild.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 eng/build.ps1           | 20 ++++++++++++++++++--
 eng/build.sh            | 17 +++++++++++++++--
 eng/pipelines/build.yml |  1 -
 src/tests/dirs.proj     |  6 +++---
 4 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/eng/build.ps1 b/eng/build.ps1
index 632edd263c..0f64647493 100644
--- a/eng/build.ps1
+++ b/eng/build.ps1
@@ -125,11 +125,27 @@ if ($test) {
         }
 
         # When the managed build was skipped (e.g. the test-only CI legs that download prebuilt
-        # product binaries), the test SDK, runtimes, and debuggees that are normally produced by
-        # the managed build (InstallRuntimes.proj + BuildDebuggees in src/tests/dirs.proj) were
+        # product binaries), the debuggees built by BuildDebuggees in src/tests/dirs.proj were
         # downloaded as part of TestArtifacts. Skip rebuilding them so this leg only runs tests.
+        # Test runtimes are still installed locally below (cheap, ensures correct file permissions).
         $skipTestArtifactsBuild = if ($skipmanaged) { 'true' } else { 'false' }
 
+        # The managed build normally installs the test SDK/runtimes via an InstallRuntimes.proj
+        # ProjectReference. The -test step runs with Build=false, so install them explicitly here.
+        if ($skipmanaged) {
+            & "$engroot\common\build.ps1" `
+              -restore -build `
+              -projects "$engroot\InstallRuntimes.proj" `
+              -configuration $configuration `
+              -verbosity $verbosity `
+              -ci:$ci `
+              /p:TargetOS=$os `
+              /p:TargetArch=$architecture
+            if ($lastExitCode -ne 0) {
+                exit $lastExitCode
+            }
+        }
+
         & "$engroot\common\build.ps1" `
           -test `
           -restore:$skipmanaged `
diff --git a/eng/build.sh b/eng/build.sh
index b6053294ae..76a5874586 100755
--- a/eng/build.sh
+++ b/eng/build.sh
@@ -354,14 +354,27 @@ if [[ "$__Test" == 1 ]]; then
       fi
 
       # When the managed build was skipped (e.g. the test-only CI legs that download prebuilt
-      # product binaries), the test SDK, runtimes, and debuggees that are normally produced by
-      # the managed build (InstallRuntimes.proj + BuildDebuggees in src/tests/dirs.proj) were
+      # product binaries), the debuggees built by BuildDebuggees in src/tests/dirs.proj were
       # downloaded as part of TestArtifacts. Skip rebuilding them so this leg only runs tests.
+      # Test runtimes are still installed locally below (cheap, ensures correct file permissions).
       __TestRestoreArg=
       __SkipTestArtifactsBuild=false
       if [[ "$__ManagedBuild" == 0 ]]; then
           __TestRestoreArg=--restore
           __SkipTestArtifactsBuild=true
+
+          # The managed build normally installs the test SDK/runtimes via an InstallRuntimes.proj
+          # ProjectReference. The --test step runs with Build=false, so install them explicitly here.
+          "$__RepoRootDir/eng/common/build.sh" \
+            --restore --build \
+            --projects "$__RepoRootDir/eng/InstallRuntimes.proj" \
+            --configuration "$__BuildType" \
+            /p:TargetArch="$__TargetArch" \
+            /p:TargetRid="$__TargetRid" \
+            $__CommonMSBuildArgs
+          if [ $? != 0 ]; then
+              exit 1
+          fi
       fi
 
       # __CommonMSBuildArgs contains TargetOS property
diff --git a/eng/pipelines/build.yml b/eng/pipelines/build.yml
index 7906f41137..0b90f515f8 100644
--- a/eng/pipelines/build.yml
+++ b/eng/pipelines/build.yml
@@ -218,7 +218,6 @@ jobs:
             Contents: |
               bin/**
               test/**
-              dotnet-test/**
             TargetFolder: $(Build.ArtifactStagingDirectory)/testartifacts
 
         - template: /eng/pipelines/publish-pipeline-artifact-shim.yml@self
diff --git a/src/tests/dirs.proj b/src/tests/dirs.proj
index aef9406cb7..a37899c9ce 100644
--- a/src/tests/dirs.proj
+++ b/src/tests/dirs.proj
@@ -17,9 +17,9 @@
     <!-- Install test runtimes (SDK, shared frameworks) into artifacts/dotnet-test/.
          Using ProjectReference ensures the install runs exactly once via MSBuild's
          result cache, even when multiple test projects depend on it.
-         Skipped on test-only legs ($(SkipTestArtifactsBuild)) which download a
-         prebuilt artifacts/dotnet-test directory instead of installing locally. -->
-    <ProjectReference Include="$(RepositoryEngineeringDir)InstallRuntimes.proj" ReferenceOutputAssembly="false" SkipGetTargetFrameworkProperties="true" Condition="'$(SkipTestArtifactsBuild)' != 'true'" />
+         Test-only legs install runtimes locally too (cheap, gets correct file perms)
+         and only skip the expensive debuggee rebuild via $(SkipTestArtifactsBuild). -->
+    <ProjectReference Include="$(RepositoryEngineeringDir)InstallRuntimes.proj" ReferenceOutputAssembly="false" SkipGetTargetFrameworkProperties="true" />
   </ItemGroup>
 
   <!--

From 17e228064cb52b16157933c55ba5922cdeab2303 Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Mon, 29 Jun 2026 17:23:42 -0700
Subject: [PATCH 06/10] Move tests back to net10 and drop tools.runtimes net8
 node

The clrmd 4.1 bump in main (#5913) carries the .NET 8 fix, so the unit tests can run on net10 again. Since the live SDK already ships the net10 runtime, the net8 shared runtime no longer needs to be installed via global.json's tools.runtimes node. Reverts the temporary 'Keep tests on net8' workaround.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 Directory.Build.props                                | 10 +++++++++-
 global.json                                          | 10 +---------
 src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj |  2 +-
 ...rosoft.Diagnostics.DebugServices.UnitTests.csproj |  2 +-
 .../EventLogsPipelineUnitTests.cs                    | 12 ++++++------
 .../Microsoft.FileFormats.UnitTests.csproj           |  2 +-
 .../Microsoft.SymbolStore.UnitTests.csproj           |  2 +-
 src/tests/SOS.UnitTests/SOS.UnitTests.csproj         |  2 +-
 .../dotnet-counters/DotnetCounters.UnitTests.csproj  |  2 +-
 src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj  |  2 +-
 10 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/Directory.Build.props b/Directory.Build.props
index 9fe222dc98..e6a583c5c6 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -69,10 +69,18 @@
      -->
     <NetCoreAppMinVersion>8.0</NetCoreAppMinVersion>
     <NetCoreAppMinTargetFramework>net$(NetCoreAppMinVersion)</NetCoreAppMinTargetFramework>
+    <!--
+        The TFM our unit tests run as. The tools must remain on $(NetCoreAppMinTargetFramework),
+        but the tests run on the SDK version from global.json, so they can target a newer TFM.
+        Keeping the tests on the live SDK's TFM means the SDK already ships the matching runtime,
+        so no extra shared runtime needs to be installed via global.json's tools.runtimes node.
+     -->
+    <NetCoreAppTestVersion>10.0</NetCoreAppTestVersion>
+    <NetCoreAppTestTargetFramework>net$(NetCoreAppTestVersion)</NetCoreAppTestTargetFramework>
     <!-- This is the list of TFMs we build our debuggees and tracees as. -->
     <SupportedSubProcessTargetFrameworks>net8.0;net9.0;net10.0;net11.0</SupportedSubProcessTargetFrameworks>
     <!-- This is the list of TFMs we build our unit tests as. -->
-    <SupportedXUnitTestTargetFrameworks>net8.0</SupportedXUnitTestTargetFrameworks>
+    <SupportedXUnitTestTargetFrameworks>$(NetCoreAppTestTargetFramework)</SupportedXUnitTestTargetFrameworks>
   </PropertyGroup>
 
 </Project>
diff --git a/global.json b/global.json
index 75792e25d1..c212145c75 100644
--- a/global.json
+++ b/global.json
@@ -5,15 +5,7 @@
     "rollForward": "major"
   },
   "tools": {
-    "dotnet": "10.0.108",
-    "runtimes": {
-      "dotnet": [
-        "$(MicrosoftNETCoreApp80Version)"
-      ],
-      "dotnet/x86": [
-        "$(MicrosoftNETCoreApp80Version)"
-      ]
-    }
+    "dotnet": "10.0.108"
   },
   "msbuild-sdks": {
     "Microsoft.Build.NoTargets": "3.7.0",
diff --git a/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj b/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj
index c931e79852..3b9c84c185 100644
--- a/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj
+++ b/src/tests/DbgShim.UnitTests/DbgShim.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <DbgShimConfigFileName>$(OutputPath)$(TargetFramework)\Debugger.Tests.Common.txt</DbgShimConfigFileName>
     <TestAssetsVersion>1.0.351101</TestAssetsVersion>
diff --git a/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj b/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj
index 9a4014149c..e71b2f7d7f 100644
--- a/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj
+++ b/src/tests/Microsoft.Diagnostics.DebugServices.UnitTests/Microsoft.Diagnostics.DebugServices.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <DebugServicesConfigFileName>$(OutputPath)$(TargetFramework)\Debugger.Tests.Common.txt</DebugServicesConfigFileName>
     <TestAssetsVersion>1.0.351101</TestAssetsVersion>
     <!-- Controls the test asset package restore and the tests that use them -->
diff --git a/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs b/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs
index c8ed1e4f24..1b1d00e0e8 100644
--- a/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs
+++ b/src/tests/Microsoft.Diagnostics.Monitoring.EventPipe/EventLogsPipelineUnitTests.cs
@@ -62,7 +62,7 @@ public async Task TestLogsAllCategoriesAllLevels(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -84,7 +84,7 @@ public async Task TestLogsAllCategoriesDefaultLevel(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -116,7 +116,7 @@ public async Task TestLogsAllCategoriesDefaultLevelFallback(TestConfiguration co
             ValidateLoggerRemoteCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -157,7 +157,7 @@ public async Task TestLogsUseAppFilters(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -182,7 +182,7 @@ public async Task TestLogsUseAppFiltersAndFilterSpecs(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         /// <summary>
@@ -213,7 +213,7 @@ public async Task TestLogsWildcardCategory(TestConfiguration config)
             ValidateAppLoggerCategoryWarningMessage(reader);
             ValidateAppLoggerCategoryErrorMessage(reader);
 
-            Assert.True(reader.EndOfStream, "Expected to have read all entries from stream.");
+            Assert.True(string.IsNullOrEmpty(await reader.ReadToEndAsync()), "Expected to have read all entries from stream.");
         }
 
         private async Task<Stream> GetLogsAsync(TestConfiguration config, Action<EventLogsPipelineSettings> settingsCallback = null)
diff --git a/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj b/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj
index 808617aa05..513ca6baa5 100644
--- a/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj
+++ b/src/tests/Microsoft.FileFormats.UnitTests/Microsoft.FileFormats.UnitTests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <NoWarn>;1591;1701</NoWarn>
   </PropertyGroup>
 
diff --git a/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj b/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj
index e2dc9e42a7..3805aa1334 100644
--- a/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj
+++ b/src/tests/Microsoft.SymbolStore.UnitTests/Microsoft.SymbolStore.UnitTests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <NoWarn>;1591;1701</NoWarn>
   </PropertyGroup>
 
diff --git a/src/tests/SOS.UnitTests/SOS.UnitTests.csproj b/src/tests/SOS.UnitTests/SOS.UnitTests.csproj
index d2f3b4cbb7..df9a23e046 100644
--- a/src/tests/SOS.UnitTests/SOS.UnitTests.csproj
+++ b/src/tests/SOS.UnitTests/SOS.UnitTests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
     <IsPackable>false</IsPackable>
     <NoWarn>;1591;1701</NoWarn>
     <DefineConstants>$(DefineConstants);CORE_CLR</DefineConstants>
diff --git a/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj b/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj
index aa872e9b45..6472bcfb65 100644
--- a/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj
+++ b/src/tests/dotnet-counters/DotnetCounters.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj b/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj
index 9d70543023..056dd23295 100644
--- a/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj
+++ b/src/tests/dotnet-trace/DotnetTrace.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>$(NetCoreAppMinTargetFramework)</TargetFramework>
+    <TargetFramework>$(NetCoreAppTestTargetFramework)</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

From 2409ca22f86fdcc0e26d9c18612c9a2c6e65ebe9 Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Mon, 29 Jun 2026 20:16:03 -0700
Subject: [PATCH 07/10] Install x86 net10 runtime for x86 test host

The x86 test legs failed because Arcade launches the xUnit runner via
$(DotNetRoot)x86/dotnet.exe and silently falls back to the x64 host when
that path is missing. Without an x86 runtime in .dotnet/x86, the runner ran
64-bit, so the DbgShim/SOS harness resolved the native binary directory from
the process architecture as Windows_NT.x64.Release and failed to load the
x86 dbgshim.dll/SOS bits.

Restore the tools.runtimes dotnet/x86 entry (pointed at net10) so Arcade
provisions the x86 host the test runner needs. dotnet-test only provides the
arch-matched runtime for debuggees, not the runner host itself.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 global.json | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/global.json b/global.json
index c212145c75..979ba15a3a 100644
--- a/global.json
+++ b/global.json
@@ -5,7 +5,12 @@
     "rollForward": "major"
   },
   "tools": {
-    "dotnet": "10.0.108"
+    "dotnet": "10.0.108",
+    "runtimes": {
+      "dotnet/x86": [
+        "$(MicrosoftNETCoreApp100Version)"
+      ]
+    }
   },
   "msbuild-sdks": {
     "Microsoft.Build.NoTargets": "3.7.0",

From 6fce10de133b504cf99499b1d278e9ea021d25e3 Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Tue, 30 Jun 2026 00:03:10 -0700
Subject: [PATCH 08/10] Publish obj artifacts and use test.cmd/test.sh for
 test-only legs

- Include obj/** in the published TestArtifacts so the test-only legs have the
  MSBuild intermediate outputs. Without them the incremental up-to-date check
  misses and CoreCompile/Csc re-runs for product and test projects on the test
  leg even though bin/** was downloaded.
- Test-only legs now invoke test.cmd/test.sh, which already encode
  '-test -skipmanaged -skipnative' and do not prepend the inert '-restore -build'
  that build.cmd/build.sh add.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 eng/pipelines/build.yml | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/eng/pipelines/build.yml b/eng/pipelines/build.yml
index 0b90f515f8..d6b95a98ad 100644
--- a/eng/pipelines/build.yml
+++ b/eng/pipelines/build.yml
@@ -134,16 +134,24 @@ jobs:
       - _TestArgs: '-test'
       - _Cross: ''
 
-      - ${{ if eq(parameters.osGroup, 'Windows_NT') }}:
-        - _buildScript: $(Build.SourcesDirectory)\build.cmd
-      - ${{ if ne(parameters.osGroup, 'Windows_NT') }}:
-        - _buildScript: $(Build.SourcesDirectory)/build.sh
-
       - ${{ if and(eq(parameters.testOnly, 'true'), eq(parameters.buildOnly, 'true')) }}:
         'error, testOnly and buildOnly cannot be true at the same time': error
 
+      # Test-only legs invoke test.cmd/test.sh, which already encode
+      # '-test -skipmanaged -skipnative' and do not prepend '-restore -build'. All other legs
+      # (build-only and build+test) use build.cmd/build.sh, which prepend '-restore -build'.
       - ${{ if eq(parameters.testOnly, 'true') }}:
-        - _TestArgs: '-test -skipnative -skipmanaged'
+        - ${{ if eq(parameters.osGroup, 'Windows_NT') }}:
+          - _buildScript: $(Build.SourcesDirectory)\test.cmd
+        - ${{ if ne(parameters.osGroup, 'Windows_NT') }}:
+          - _buildScript: $(Build.SourcesDirectory)/test.sh
+        - _TestArgs: ''
+
+      - ${{ if ne(parameters.testOnly, 'true') }}:
+        - ${{ if eq(parameters.osGroup, 'Windows_NT') }}:
+          - _buildScript: $(Build.SourcesDirectory)\build.cmd
+        - ${{ if ne(parameters.osGroup, 'Windows_NT') }}:
+          - _buildScript: $(Build.SourcesDirectory)/build.sh
 
       - ${{ if eq(parameters.buildOnly, 'true') }}:
         - _TestArgs: ''
@@ -217,6 +225,7 @@ jobs:
             SourceFolder: '$(Build.SourcesDirectory)/artifacts'
             Contents: |
               bin/**
+              obj/**
               test/**
             TargetFolder: $(Build.ArtifactStagingDirectory)/testartifacts
 

From be8763ff7ce096e0a99e833af74b63b68ce93d59 Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Tue, 30 Jun 2026 12:10:57 -0700
Subject: [PATCH 09/10] Drop Traversal Test->Build dependency on prebuilt test
 legs

The Microsoft.Build.Traversal SDK hardcodes TestDependsOn=Build, so every
traversal's Test target (build.proj, src/dirs.proj, src/tests/dirs.proj)
rebuilds its entire subgraph before running tests, regardless of whether
-build was passed. On the test-only CI legs the product and test binaries
are downloaded as prebuilt TestArtifacts; rebuilding them is wasted work,
and because pipeline artifact downloads do not preserve file timestamps the
incremental check fails and it becomes a full recompile.

Override TestDependsOn (empty) via CustomAfterTraversalTargets when the
managed build was skipped (SkipTestArtifactsBuild=true, set by build.ps1/
build.sh for -skipmanaged). The Test target still invokes Test on each
referenced project, so tests run directly against the downloaded binaries.

Validated locally: test leg binlog shows Csc=0, CoreCompile not invoked,
RunTests executed on all test projects.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 Directory.Build.props          |  6 ++++++
 eng/TraversalOverrides.targets | 22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 eng/TraversalOverrides.targets

diff --git a/Directory.Build.props b/Directory.Build.props
index e6a583c5c6..0f9ee24cc2 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -22,6 +22,12 @@
     <RepositoryName>diagnostics</RepositoryName>
   </PropertyGroup>
 
+  <!-- Inject overrides that must run after the Microsoft.Build.Traversal SDK targets
+       (e.g. dropping the Test->Build dependency on prebuilt test-only legs). -->
+  <PropertyGroup>
+    <CustomAfterTraversalTargets>$(MSBuildThisFileDirectory)eng/TraversalOverrides.targets</CustomAfterTraversalTargets>
+  </PropertyGroup>
+
   <Import Project="Sdk.props" Sdk="Microsoft.DotNet.Arcade.Sdk" />
 
   <!--
diff --git a/eng/TraversalOverrides.targets b/eng/TraversalOverrides.targets
new file mode 100644
index 0000000000..684b964d4d
--- /dev/null
+++ b/eng/TraversalOverrides.targets
@@ -0,0 +1,22 @@
+<Project>
+
+  <!--
+    Imported via $(CustomAfterTraversalTargets) after the Microsoft.Build.Traversal SDK targets,
+    so it can override properties the SDK sets unconditionally.
+
+    The Traversal SDK hardcodes <TestDependsOn>Build</TestDependsOn>, which makes every traversal's
+    "Test" target build its entire subgraph (product + tests + their project references) before
+    running tests, regardless of whether -build was passed. On the test-only CI legs the product and
+    test binaries are downloaded as prebuilt TestArtifacts, so rebuilding them is pure waste - and
+    because pipeline artifact downloads do not preserve file timestamps, the up-to-date check fails
+    and it becomes a full recompile.
+
+    Drop the Build dependency when the managed build was skipped ($(SkipTestArtifactsBuild) is set by
+    build.ps1 / build.sh for -skipmanaged). The traversal "Test" target still invokes "Test" on each
+    referenced project, so tests run directly against the downloaded binaries with no build.
+  -->
+  <PropertyGroup Condition="'$(SkipTestArtifactsBuild)' == 'true'">
+    <TestDependsOn></TestDependsOn>
+  </PropertyGroup>
+
+</Project>

From fc39af3438a30f0773da363a261f892d70d538dc Mon Sep 17 00:00:00 2001
From: Juan Hoyos <19413848+hoyosjs@users.noreply.github.com>
Date: Tue, 30 Jun 2026 15:47:20 -0700
Subject: [PATCH 10/10] Reduce verbose MSBuild logging in test/debuggee builds

Lower the importance of two diagnostic messages that were emitted at High
importance (shown even at minimal verbosity) and added noise to every build:

- SdkPackOverrides.targets: OverrideTestingVersions message -> Low
  (folds in dotnet/diagnostics#5869).
- Debuggees Directory.Build.targets: interpreter-test skip message -> default
  importance.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 eng/AuxMsbuildFiles/SdkPackOverrides.targets              | 2 +-
 src/tests/SOS.UnitTests/Debuggees/Directory.Build.targets | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/eng/AuxMsbuildFiles/SdkPackOverrides.targets b/eng/AuxMsbuildFiles/SdkPackOverrides.targets
index a2c3023663..94e01592e9 100644
--- a/eng/AuxMsbuildFiles/SdkPackOverrides.targets
+++ b/eng/AuxMsbuildFiles/SdkPackOverrides.targets
@@ -13,7 +13,7 @@
        <AspNetVersion11>@(RuntimeTestVersions->WithMetadataValue('TargetFramework', 'net11.0')->Metadata('AspNet'))</AspNetVersion11>
     </PropertyGroup>
 
-    <Message Importance="High" Text="OverrideTestingVersions: RuntimeTestVersions='@(RuntimeTestVersions)'" />
+    <Message Importance="Low" Text="OverrideTestingVersions: RuntimeTestVersions=@(RuntimeTestVersions -> '%(Runtime)')" />
 
     <!-- Skip overrides when RuntimeTestVersions is not populated (e.g. test-time CLI builds
          where eng/Versions.props is not imported). The SDK's built-in versions are used instead. -->
diff --git a/src/tests/SOS.UnitTests/Debuggees/Directory.Build.targets b/src/tests/SOS.UnitTests/Debuggees/Directory.Build.targets
index 309df60cdd..3671dfe974 100644
--- a/src/tests/SOS.UnitTests/Debuggees/Directory.Build.targets
+++ b/src/tests/SOS.UnitTests/Debuggees/Directory.Build.targets
@@ -40,8 +40,7 @@
   </PropertyGroup>
 
   <Target Name="_SkipUngatedInterpreterTestBuild">
-    <Message Importance="High"
-             Text="Skipping interpreter-test debuggee '$(MSBuildProjectName)' because SOS_TEST_INTERPRETER is not set. Set SOS_TEST_INTERPRETER=true (or pass -testInterpreter to Build.cmd / build.sh) to enable." />
+    <Message Text="Skipping interpreter-test debuggee '$(MSBuildProjectName)' because SOS_TEST_INTERPRETER is not set. Set SOS_TEST_INTERPRETER=true (or pass -testInterpreter to Build.cmd / build.sh) to enable." />
   </Target>
 
 </Project>