Fix race condition in Microsoft.Extensions.Configuration test (#120242)

Fixes #109904

Author: jkotas

src/libraries/Microsoft.Extensions.Configuration.EnvironmentVariables/tests/EnvironmentVariablesTest.cs

@@ -285,27 +285,6 @@ public void AddEnvironmentVariablesUsingPrefixWithDoubleUnderscores_Bind_PrefixM
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         public void BindingDoesNotThrowIfReloadedDuringBinding()
-        {
-            // Instrumentation for https://github.com/dotnet/runtime/issues/109904. Failfast to generate a crash dump when the test fails with NullReferenceException.
-            try
-            {
-                BindingDoesNotThrowIfReloadedDuringBindingWorker();
-            }
-            catch (NullReferenceException) when (FailFast())
-            {
-            }
-
-            static bool FailFast()
-            {
-                Environment.FailFast(
-                    "Instrumentation for https://github.com/dotnet/runtime/issues/109904" + Environment.NewLine +
-                    "Microsoft.Extensions.Configuration.EnvironmentVariables.Test.EnvironmentVariablesTest.BindingDoesNotThrowIfReloadedDuringBinding [FAIL]" + Environment.NewLine +
-                    "System.NullReferenceException : Object reference not set to an instance of an object.");
-                return false;
-            }
-        }
-
-        private void BindingDoesNotThrowIfReloadedDuringBindingWorker()
         {
             var dic = new Dictionary<string, string>
             {
@@ -317,8 +296,6 @@ private void BindingDoesNotThrowIfReloadedDuringBindingWorker()
             configurationBuilder.AddEnvironmentVariables();
             var config = configurationBuilder.Build();
 
-            MyOptions options = null;
-
             using (var cts = new CancellationTokenSource(TimeSpan.FromMilliseconds(250)))
             {
                 void ReloadLoop()
@@ -331,14 +308,17 @@ void ReloadLoop()
 
                 _ = Task.Run(ReloadLoop);
 
-                while (!cts.IsCancellationRequested)
+                MyOptions options;
+
+                do
                 {
                     options = config.Get<MyOptions>();
                 }
-            }
+                while (!cts.IsCancellationRequested);
 
-            Assert.Equal(-2, options.Number);
-            Assert.Equal("Foo", options.Text);
+                Assert.Equal(-2, options.Number);
+                Assert.Equal("Foo", options.Text);
+            }
         }
 
         private sealed class MyOptions

src/libraries/Microsoft.Extensions.Configuration/tests/FunctionalTests/ConfigurationTests.cs

@@ -966,23 +966,19 @@ void ReloadLoop()
 
                 _ = Task.Run(ReloadLoop);
 
-                MyOptions options = null;
+                MyOptions options;
 
-                bool optionsInitialized = false;
-                while (!cts.IsCancellationRequested)
+                do
                 {
                     options = config.Get<MyOptions>();
-                    optionsInitialized = true;
                 }
+                while (!cts.IsCancellationRequested);
 
-                if (optionsInitialized)
-                {
-                    Assert.Equal("CmdValue1", options.CmdKey1);
-                    Assert.Equal("IniValue1", options.IniKey1);
-                    Assert.Equal("JsonValue1", options.JsonKey1);
-                    Assert.Equal("MemValue1", options.MemKey1);
-                    Assert.Equal("XmlValue1", options.XmlKey1);
-                }
+                Assert.Equal("CmdValue1", options.CmdKey1);
+                Assert.Equal("IniValue1", options.IniKey1);
+                Assert.Equal("JsonValue1", options.JsonKey1);
+                Assert.Equal("MemValue1", options.MemKey1);
+                Assert.Equal("XmlValue1", options.XmlKey1);
             }
         }