Fixing test on uap by adding ExitCode to RemoteInvokeHandle (#28413)

Fixes #28400

Author: maryamariyan

src/CoreFx.Private.TestUtilities/ref/CoreFx.Private.TestUtilities.cs

@@ -146,6 +146,7 @@ protected RemoteExecutorTestBase() { }
         public sealed partial class RemoteInvokeHandle : System.IDisposable
         {
             public RemoteInvokeHandle(System.Diagnostics.Process process, System.Diagnostics.RemoteInvokeOptions options, string assemblyName, string className, string methodName) { }
+            public int ExitCode { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
             public System.Diagnostics.RemoteInvokeOptions Options { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
             public System.Diagnostics.Process Process { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
             public void Dispose() { }

src/CoreFx.Private.TestUtilities/src/System/Diagnostics/RemoteExecutorTestBase.cs

@@ -195,6 +195,27 @@ public RemoteInvokeHandle(Process process, RemoteInvokeOptions options, string a
                 MethodName = methodName;
             }
 
+            private int _exitCode;
+            public int ExitCode
+            {
+                get
+                {
+                    if (!PlatformDetection.IsUap)
+                    {
+                        Process.WaitForExit();
+                        return Process.ExitCode;
+                    }
+                    return _exitCode;
+                }
+                internal set
+                {
+                    if (!PlatformDetection.IsUap)
+                    {
+                        throw new PlatformNotSupportedException("ExitCode property can only be set in UWP");
+                    }
+                    _exitCode = value;
+                }
+            }
             public Process Process { get; set; }
             public RemoteInvokeOptions Options { get; private set; }
             public string AssemblyName { get; private set; }

src/CoreFx.Private.TestUtilities/src/System/Diagnostics/RemoteExecutorTestBase.uap.cs

@@ -36,6 +36,7 @@ private static RemoteInvokeHandle RemoteInvoke(MethodInfo method, string[] args,
             // that the method to invoke is available because we're already running in this assembly.
             Type t = method.DeclaringType;
             Assembly a = t.GetTypeInfo().Assembly;
+            int exitCode;
 
             using (AppServiceConnection remoteExecutionService = new AppServiceConnection())
             {
@@ -65,12 +66,13 @@ private static RemoteInvokeHandle RemoteInvoke(MethodInfo method, string[] args,
                 AppServiceResponse response = remoteExecutionService.SendMessageAsync(message).GetAwaiter().GetResult();
 
                 Assert.True(response.Status == AppServiceResponseStatus.Success, $"response.Status = {response.Status}");
-                int res = (int)response.Message["Results"];
-                Assert.True(!options.CheckExitCode || res == options.ExpectedExitCode, (string)response.Message["Log"] + Environment.NewLine + $"Returned Error code: {res}");
+                exitCode = (int)response.Message["Results"];
+                Assert.True(!options.CheckExitCode || exitCode == options.ExpectedExitCode, (string)response.Message["Log"] + Environment.NewLine + $"Returned Error code: {exitCode}");
             }
-
             // RemoteInvokeHandle is not really needed in the UAP scenario but we use it just to have consistent interface as non UAP
-            return new RemoteInvokeHandle(null, options, null, null, null);
+            var handle = new RemoteInvokeHandle(null, options, null, null, null);
+            handle.ExitCode = exitCode;
+            return handle;
         }
     }
 }

src/System.Runtime/tests/System/StringGetHashCodeTests.cs

@@ -20,17 +20,15 @@ public class StringGetHashCodeTests : RemoteExecutorTestBase
         [MemberData(nameof(GetHashCode_TestData))]
         public void GetHashCodeWithStringComparer_UseSameStringInTwoProcesses_ReturnsDifferentHashCodes(int getHashCodeIndex)
         {
-            Func<string, string, int> method = (parentHash, i) => { return int.Parse(parentHash) != s_GetHashCodes[int.Parse(i)]() ? SuccessExitCode : -1; };
+            Func<string, string, int> method = (parentHash, i) => int.Parse(parentHash) != s_GetHashCodes[int.Parse(i)]() ? SuccessExitCode : -1;
             int parentHashCode = s_GetHashCodes[getHashCodeIndex]();
             int exitCode, retry = 0;
             do
             {
                 // very small chance the child and parent hashcode are the same. To further reduce chance of collision we try up to 3 times
                 using (RemoteInvokeHandle handle = RemoteInvoke(method, parentHashCode.ToString(), getHashCodeIndex.ToString(), new RemoteInvokeOptions { CheckExitCode = false }))
                 {
-                    Process p = handle.Process;
-                    p.WaitForExit();
-                    exitCode = p.ExitCode;
+                    exitCode = handle.ExitCode;
                     retry++;
                 }
             } while (exitCode != SuccessExitCode && retry < 3);