Making Project Tools use the CLI shared runtime if they have the prefercliruntime in the root of their package. This allows for project tools to not have to change when a new runtime comes up as long as they are compatible with the runtime that the CLI is using.

test/EndToEnd/GivenDotNetUsesMSBuild.cs

@@ -69,6 +69,25 @@ namespace Microsoft.DotNet.Tests.EndToEnd
                 .HaveStdOutContaining("Hello Portable World!");;
         }
 
+        [Fact]
+        public void ItCanRunToolsThatPrefersTheCliRuntime()
+        {
+            var testInstance = TestAssets.Get("MSBuildTestApp")
+                                         .CreateInstance()
+                                         .WithSourceFiles()
+                                         .WithRestoreFiles();
+
+            var testProjectDirectory = testInstance.Root;
+
+            new DotnetCommand()
+                .WithWorkingDirectory(testInstance.Root)
+                .ExecuteWithCapturedOutput("prefercliruntime")
+                .Should()
+                .Pass()
+                .And
+                .HaveStdOutContaining("Hello I prefer the cli runtime World!");;
+        }
+
         [Fact]
         public void ItCanRunAToolThatInvokesADependencyToolInACSProj()
         {