test(Transaction): PreparedAsync: null, empty cases

Author: HackPoint

csharp/src/Apache.Arrow.Flight.Sql/Transaction.cs

@@ -15,7 +15,7 @@
 
 namespace Apache.Arrow.Flight.Sql;
 
-using Google.Protobuf; // Ensure you have the Protobuf dependency
+using Google.Protobuf;
 
 public readonly struct Transaction
 {
@@ -37,12 +37,21 @@ public Transaction(string transactionId)
         _transactionId = ByteString.CopyFromUtf8(transactionId);
     }
 
-    public bool IsValid() => _transactionId.Length > 0;
+    public bool IsValid() => TransactionId.Length > 0;
 
-    public override bool Equals(object? obj) => obj is Transaction other && _transactionId.Equals(other._transactionId);
+    public override bool Equals(object? obj)
+    {
+        if (obj is not Transaction other)
+            return false;
+
+        // Safe compare even if _transactionId is null (from default(Transaction))  
+        return (_transactionId ?? TransactionIdDefaultValue)
+            .Equals(other._transactionId);
+    }
 
-    public override int GetHashCode() => _transactionId.GetHashCode();
+    public override int GetHashCode() => (_transactionId ?? TransactionIdDefaultValue).GetHashCode();
+    
 
     public static bool operator ==(Transaction left, Transaction right) => left.Equals(right);
     public static bool operator !=(Transaction left, Transaction right) => !left.Equals(right);
-}
+}

csharp/test/Apache.Arrow.Flight.Sql.Tests/FlightSqlClientTests.cs

@@ -96,12 +96,17 @@ public async Task RollbackTransactionAsync()
 
     #region PreparedStatement
 
-    [Fact]
-    public async Task PreparedAsync()
+    [Theory]
+    [InlineData("sample-transaction-id", true)]
+    [InlineData(null, false)]
+    public async Task PreparedAsync(string transactionId, bool expectTransaction)
     {
         // Arrange
         string query = "INSERT INTO users (id, name) VALUES (1, 'John Doe')";
-        var transaction = new Transaction("sample-transaction-id");
+        var transaction = string.IsNullOrEmpty(transactionId)
+            ? Transaction.NoTransaction
+            : new Transaction(transactionId);
+
         var flightDescriptor = FlightDescriptor.CreateCommandDescriptor("test");
 
         // Create a sample schema for the dataset and parameters
@@ -131,7 +136,15 @@ public async Task PreparedAsync()
         };
 
         // Act
-        var preparedStatement = await _flightSqlClient.PrepareAsync(query, transaction);
+        PreparedStatement preparedStatement;
+        if (expectTransaction)
+        {
+             preparedStatement = await _flightSqlClient.PrepareAsync(query, transaction);
+        }
+        else
+        {
+            preparedStatement = await _flightSqlClient.PrepareAsync(query);
+        }
         var deserializedDatasetSchema =
             SchemaExtensions.DeserializeSchema(preparedStatementResponse.DatasetSchema.ToByteArray());
         var deserializedParameterSchema =