[Templating] Enforce selenium tests runs on the expected platforms (#11602)

* Will cause the CI environment to fail if the E2E tests stop running by accident.

src/ProjectTemplates/test/RazorComponentsTemplateTest.cs

@@ -56,6 +56,10 @@ namespace Templates.Test
                     aspNetProcess.VisitInBrowser(Browser);
                     TestBasicNavigation();
                 }
+                else
+                {
+                    BrowserFixture.EnforceSupportedConfigurations();
+                }
             }
 
             using (var aspNetProcess = Project.StartPublishedProjectAsync())
@@ -70,6 +74,10 @@ namespace Templates.Test
                     aspNetProcess.VisitInBrowser(Browser);
                     TestBasicNavigation();
                 }
+                else
+                {
+                    BrowserFixture.EnforceSupportedConfigurations();
+                }
             }
         }
 
@@ -106,8 +114,13 @@ namespace Templates.Test
                     aspNetProcess.VisitInBrowser(Browser);
                     TestBasicNavigation();
                 }
+                else
+                {
+                    BrowserFixture.EnforceSupportedConfigurations();
+                }
             }
 
+
             using (var aspNetProcess = Project.StartPublishedProjectAsync())
             {
                 Assert.False(

src/ProjectTemplates/test/SpaTemplateTest/SpaTemplateTestBase.cs

@@ -113,6 +113,10 @@ namespace Templates.Test.SpaTemplateTest
                     aspNetProcess.VisitInBrowser(browser);
                     TestBasicNavigation(visitFetchData: shouldVisitFetchData, usesAuth, browser, logs);
                 }
+                else
+                {
+                    BrowserFixture.EnforceSupportedConfigurations();
+                }
             }
 
             if (usesAuth)
@@ -135,6 +139,10 @@ namespace Templates.Test.SpaTemplateTest
                     aspNetProcess.VisitInBrowser(browser);
                     TestBasicNavigation(visitFetchData: shouldVisitFetchData, usesAuth, browser, logs);
                 }
+                else
+                {
+                    BrowserFixture.EnforceSupportedConfigurations();
+                }
             }
         }
 

src/Shared/E2ETesting/BrowserFixture.cs

@@ -6,6 +6,7 @@ using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Linq;
 using System.Reflection;
+using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using OpenQA.Selenium;
 using OpenQA.Selenium.Chrome;
@@ -28,6 +29,14 @@ namespace Microsoft.AspNetCore.E2ETesting
 
         public IMessageSink DiagnosticsMessageSink { get; }
 
+        public static void EnforceSupportedConfigurations()
+        {
+            // Do not change the current platform support without explicit approval.
+            Assert.False(
+                RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && RuntimeInformation.ProcessArchitecture == Architecture.X64,
+                "Selenium tests should be running in this platform.");
+        }
+
         public static bool IsHostAutomationSupported()
         {
             // We emit an assemblymetadata attribute that reflects the value of SeleniumE2ETestsSupported at build