fix: Remove Sonar code smells

Author: HofmeisterAn

src/Testcontainers.Xunit/ContainerLifetime.cs

@@ -36,10 +36,16 @@ public TContainerEntity Container
 
 #if !XUNIT_V3
     /// <inheritdoc />
-    LifetimeTask IAsyncLifetime.DisposeAsync() => DisposeAsync();
+    LifetimeTask IAsyncLifetime.DisposeAsync() => DisposeAsyncCore();
 #else
     /// <inheritdoc />
-    LifetimeTask IAsyncDisposable.DisposeAsync() => DisposeAsync();
+    async LifetimeTask IAsyncDisposable.DisposeAsync()
+    {
+        await DisposeAsyncCore()
+            .ConfigureAwait(false);
+
+        GC.SuppressFinalize(this);
+    }
 #endif
 
     /// <summary>
@@ -80,7 +86,7 @@ await Container.StartAsync()
     }
 
     /// <inheritdoc cref="IAsyncLifetime" />
-    protected virtual async LifetimeTask DisposeAsync()
+    protected virtual async LifetimeTask DisposeAsyncCore()
     {
         if (_exception == null)
         {

src/Testcontainers.Xunit/DbContainerFixture.cs

@@ -25,15 +25,15 @@ await base.InitializeAsync()
     }
 
     /// <inheritdoc />
-    protected override async LifetimeTask DisposeAsync()
+    protected override async LifetimeTask DisposeAsyncCore()
     {
         if (_testMethods != null)
         {
             await _testMethods.DisposeAsync()
                 .ConfigureAwait(true);
         }
 
-        await base.DisposeAsync()
+        await base.DisposeAsyncCore()
             .ConfigureAwait(true);
     }
 

src/Testcontainers.Xunit/DbContainerTest.cs

@@ -12,7 +12,6 @@ public abstract class DbContainerTest<TBuilderEntity, TContainerEntity>(ITestOut
     where TBuilderEntity : IContainerBuilder<TBuilderEntity, TContainerEntity>, new()
     where TContainerEntity : IContainer, IDatabaseContainer
 {
-    private readonly CancellationTokenSource _cts = new CancellationTokenSource();
     private DbContainerTestMethods _testMethods;
 
     /// <inheritdoc />
@@ -25,15 +24,15 @@ await base.InitializeAsync()
     }
 
     /// <inheritdoc />
-    protected override async LifetimeTask DisposeAsync()
+    protected override async LifetimeTask DisposeAsyncCore()
     {
         if (_testMethods != null)
         {
             await _testMethods.DisposeAsync()
                 .ConfigureAwait(true);
         }
 
-        await base.DisposeAsync()
+        await base.DisposeAsyncCore()
             .ConfigureAwait(true);
     }