fix issue

ChatBot.Tests/Data/MigrationsTests.cs

@@ -10,6 +10,7 @@ public class MigrationsTests : IDisposable
 {
     private readonly ServiceProvider _serviceProvider;
     private readonly ChatBotDbContext _dbContext;
+    private bool _disposed;
 
     public MigrationsTests()
     {
@@ -324,10 +325,25 @@ public class MigrationsTests : IDisposable
         remainingMessageCount.Should().Be(0);
     }
 
-    public void Dispose()
+    protected virtual void Dispose(bool disposing)
+    {
+        if (_disposed)
+        {
+            return;
+        }
+
+        if (disposing)
         {
             _dbContext?.Dispose();
             _serviceProvider?.Dispose();
+        }
+
+        _disposed = true;
+    }
+
+    public void Dispose()
+    {
+        Dispose(true);
         GC.SuppressFinalize(this);
     }
 }