fix

ChatBot.Tests/Data/MigrationsTests.cs

@@ -58,10 +58,7 @@ public class MigrationsTests : IDisposable
     [Fact]
     public void InitialCreateMigration_ShouldHaveCorrectConstants()
     {
-        // Arrange
-        var migration = new InitialCreate();
-
-        // Act & Assert
+        // Arrange & Act & Assert
         // Use reflection to access private constants
         var migrationType = typeof(InitialCreate);
 
@@ -160,10 +157,11 @@ public class MigrationsTests : IDisposable
         var foreignKeys = chatMessageEntity.GetForeignKeys();
         foreignKeys.Should().HaveCount(1);
 
-        var foreignKey = foreignKeys[0];
+        var foreignKey = foreignKeys.First();
         foreignKey.PrincipalEntityType.Should().Be(chatSessionEntity);
-        foreignKey.Properties.Should().HaveCount(1);
-        foreignKey.Properties[0].Name.Should().Be("SessionId");
+        var properties = foreignKey.Properties;
+        properties.Should().HaveCount(1);
+        properties.First().Name.Should().Be("SessionId");
         foreignKey.DeleteBehavior.Should().Be(DeleteBehavior.Cascade);
     }