Improve the error when a project is using Microsoft.Testing.Platform

Before:
> No test result reported. Make sure your test project contains test and is compatible with VsTest.No test detected for project '~/serilog-formatting-log4net/tests/Serilog.Formatting.Log4Net.Tests.csproj'. No cause identified.

After:
> No test result reported. Make sure your test project contains test and is compatible with VsTest.
> Project '~/serilog-formatting-log4net/tests/Serilog.Formatting.Log4Net.Tests.csproj' is using Microsoft.Testing.Platform which is not yet supported by Stryker, see stryker-mutator#3094

src/Stryker.Core/Stryker.Core/Initialisation/InitialisationProcess.cs

@@ -157,9 +157,8 @@ private InitialTestRun InitialTest(IStrykerOptions options, SourceProjectInfo pr
             return result;
         }
 
-        throw new InputException(
-            "No test result reported. Make sure your test project contains test and is compatible with VsTest." +
-            string.Join(Environment.NewLine, projectInfo.Warnings));
+        const string Message = "No test result reported. Make sure your test project contains test and is compatible with VsTest.";
+        throw new InputException(string.Join(Environment.NewLine, projectInfo.Warnings.Prepend(Message)));
     }
 
     private static readonly Dictionary<string, (string assembly, string package)> TestFrameworks = new()
@@ -207,6 +206,15 @@ private void DiscoverTests(SourceProjectInfo projectInfo, ITestRunner testRunner
                 _logger.LogWarning(message);
             }
 
+            if (!causeFound && testProject.References.Any(r => r.Contains("Microsoft.Testing.Platform")))
+            {
+                causeFound = true;
+                var message = $"Project '{testProject.ProjectFilePath}' is using Microsoft.Testing.Platform which is not yet supported by Stryker, " +
+                              $"see https://github.com/stryker-mutator/stryker-net/issues/3094";
+                projectInfo.LogError(message);
+                _logger.LogWarning(message);
+            }
+
             if (causeFound)
             {
                 continue;