fix some conditional test logic to ensure we're not disabling Sockets…

…HttpHandler tests

src/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.cs

@@ -34,8 +34,6 @@ public class HttpClientHandlerTest : HttpClientTestBase
 
         private readonly NetworkCredential _credential = new NetworkCredential(Username, Password);
 
-        public static bool IsNotWindows7 => !PlatformDetection.IsWindows7;
-
         public static readonly object[][] EchoServers = Configuration.Http.EchoServers;
         public static readonly object[][] VerifyUploadServers = Configuration.Http.VerifyUploadServers;
         public static readonly object[][] CompressedServers = Configuration.Http.CompressedServers;
@@ -98,7 +96,6 @@ public class HttpClientHandlerTest : HttpClientTestBase
             GetMethods("HEAD", "TRACE");
 
         private static bool IsWindows10Version1607OrGreater => PlatformDetection.IsWindows10Version1607OrGreater;
-        private static bool NotWindowsUAPOrBeforeVersion1709 => !PlatformDetection.IsUap || PlatformDetection.IsWindows10Version1709OrGreater;
 
         private static IEnumerable<object[]> GetMethods(params string[] methods)
         {
@@ -842,9 +839,9 @@ public async Task GetAsync_AllowAutoRedirectTrue_RedirectToUriWithParams_Request
         [InlineData(3, 4)]
         public async Task GetAsync_MaxAutomaticRedirectionsNServerHops_ThrowsIfTooMany(int maxHops, int hops)
         {
-            if (PlatformDetection.IsWindows && !PlatformDetection.IsWindows10Version1703OrGreater)
+            if (IsWinHttpHandler && !PlatformDetection.IsWindows10Version1703OrGreater)
             {
-                // Skip this test if running on Windows but on a release prior to Windows 10 Creators Update.
+                // Skip this test if using WinHttpHandler but on a release prior to Windows 10 Creators Update.
                 _output.WriteLine("Skipping test due to Windows 10 version prior to Version 1703.");
                 return;
             }
@@ -1099,9 +1096,16 @@ public async Task GetAsync_CredentialIsCredentialCacheUriRedirect_StatusCodeOK(i
         }
 
         [OuterLoop] // TODO: Issue #11345
-        [ConditionalTheory(nameof(NotWindowsUAPOrBeforeVersion1709)), MemberData(nameof(HeaderWithEmptyValueAndUris))]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.Uap)]
+        [Theory]
+        [MemberData(nameof(HeaderWithEmptyValueAndUris))]
         public async Task GetAsync_RequestHeadersAddCustomHeaders_HeaderAndEmptyValueSent(string name, string value, Uri uri)
         {
+            if (IsWinHttpHandler && !PlatformDetection.IsWindows10Version1709OrGreater)
+            {
+                return;
+            }
+
             using (HttpClient client = CreateHttpClient())
             {
                 _output.WriteLine($"name={name}, value={value}");
@@ -2894,10 +2898,15 @@ public async Task Proxy_SslProxyUnsupported_Throws()
         }
 
         [SkipOnTargetFramework(TargetFrameworkMonikers.Uap, "UAP does not support custom proxies.")]
-        [ActiveIssue(23136, TestPlatforms.Windows)]
         [Fact]
         public async Task Proxy_UseSecureProxyTunnel_Success()
         {
+            if (IsWinHttpHandler)
+            {
+                // Issue #27746: WinHttpHandler hangs on this test
+                return;
+            }
+
             LoopbackServer.Options options = new LoopbackServer.Options { UseSsl = true };
 
             var listener = new TcpListener(IPAddress.Loopback, 0);

src/System.Net.Http/tests/FunctionalTests/PostScenarioTest.cs

@@ -160,9 +160,14 @@ public async Task PostNonRewindableContentUsingAuth_NoPreAuthenticate_ThrowsHttp
 
         [OuterLoop] // TODO: Issue #11345
         [Theory, MemberData(nameof(BasicAuthEchoServers))]
-        [ActiveIssue(9228, TestPlatforms.Windows)]
         public async Task PostNonRewindableContentUsingAuth_PreAuthenticate_Success(Uri serverUri)
         {
+            if (IsWinHttpHandler)
+            {
+                // Issue #9228
+                return;
+            }
+
             HttpContent content = CustomContent.Create(ExpectedContent, false);
             var credential = new NetworkCredential(UserName, Password);
             await PostUsingAuthHelper(serverUri, ExpectedContent, content, credential, preAuthenticate: true);

src/System.Net.Http/tests/FunctionalTests/ResponseStreamTest.cs

@@ -182,9 +182,9 @@ await client.GetAsync(Configuration.Http.RemoteEchoServer, HttpCompletionOption.
                 Assert.True(task.IsCompleted, "Task was not yet completed");
 
                 // Verify that the task completed successfully or is canceled.
-                if (PlatformDetection.IsWindows)
+                if (IsWinHttpHandler)
                 {
-                    // On Windows, we may fault because canceling the task destroys the request handle
+                    // With WinHttpHandler, we may fault because canceling the task destroys the request handle
                     // which may randomly cause an ObjectDisposedException (or other exception).
                     Assert.True(
                         task.Status == TaskStatus.RanToCompletion ||