Enable dotnet-watch test and remove prep.sh workaround (#15319)

src/SourceBuild/content/build.proj

@@ -119,7 +119,7 @@
 
   <Target Name="CheckIfCreateSmokeTestPrereqsExistToPack">
     <PropertyGroup>
-      <SmokeTestsArtifactsDir>$(SmokeTestsDir)bin/$(Configuration)/net7.0/</SmokeTestsArtifactsDir>
+      <SmokeTestsArtifactsDir>$(SmokeTestsDir)bin/$(Configuration)/net8.0/</SmokeTestsArtifactsDir>
       <SmokeTestsPackagesDir>$(SmokeTestsArtifactsDir)packages/</SmokeTestsPackagesDir>
     </PropertyGroup>
 

src/SourceBuild/content/prep.sh

@@ -108,9 +108,6 @@ fi
 if [ "$installDotnet" == "true" ]; then
     echo "  Installing dotnet..."
     (source ./eng/common/tools.sh && InitializeDotNetCli true)
-
-    # TODO: Remove once runtime dependency is gone
-    bash .dotnet/dotnet-install.sh --install-dir "$SCRIPT_ROOT/.dotnet" --version 7.0.0 --runtime dotnet
 fi
 
 # Build bootstrap, if specified

src/SourceBuild/content/test/Microsoft.DotNet.SourceBuild.SmokeTests/DotNetWatchTests.cs

@@ -13,7 +13,7 @@ public class DotNetWatchTests : SmokeTests
 {
     public DotNetWatchTests(ITestOutputHelper outputHelper) : base(outputHelper) { }
 
-    // [Fact] - Renable with https://github.com/dotnet/source-build/issues/3195
+    [Fact]
     public void WatchTests()
     {
         string projectDirectory = DotNetHelper.ExecuteNew(DotNetTemplate.Console.GetName(), nameof(DotNetWatchTests));

src/SourceBuild/content/test/Microsoft.DotNet.SourceBuild.SmokeTests/Microsoft.DotNet.SourceBuild.SmokeTests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
     <Nullable>enable</Nullable>
 
     <IsPackable>false</IsPackable>