fix: Adding Async Lifetime method to fix flaky unit tests

src/OpenFeature/Api.cs

@@ -29,7 +29,7 @@ public sealed class Api : IEventBus
         /// <summary>
         /// Singleton instance of Api
         /// </summary>
-        public static Api Instance { get; } = new Api();
+        public static Api Instance { get; private set; } = new Api();
 
         // Explicit static constructor to tell C# compiler
         // not to mark type as beforeFieldInit
@@ -300,5 +300,13 @@ private async Task AfterError(FeatureProvider provider, Exception? ex)
 
             await this._eventExecutor.EventChannel.Writer.WriteAsync(new Event { Provider = provider, EventPayload = eventPayload }).ConfigureAwait(false);
         }
+
+        /// <summary>
+        /// This method should only be using for testing purposes. It will reset the singleton instance of the API.
+        /// </summary>
+        internal static void ResetApi()
+        {
+            Instance = new Api();
+        }
     }
 }

test/OpenFeature.Tests/ClearOpenFeatureInstanceFixture.cs

@@ -1,14 +1,20 @@
-using System;
+using System.Threading.Tasks;
+using Xunit;
 
 namespace OpenFeature.Tests;
 
-public class ClearOpenFeatureInstanceFixture : IDisposable
+public class ClearOpenFeatureInstanceFixture : IAsyncLifetime
 {
+    public Task InitializeAsync()
+    {
+        Api.ResetApi();
+
+        return Task.CompletedTask;
+    }
+
     // Make sure the singleton is cleared between tests
-    public void Dispose()
+    public async Task DisposeAsync()
     {
-        Api.Instance.SetContext(null);
-        Api.Instance.ClearHooks();
-        Api.Instance.SetProviderAsync(new NoOpFeatureProvider()).Wait();
+        await Api.Instance.ShutdownAsync().ConfigureAwait(false);
     }
 }