diff --git a/lib/builder/transaction_block.dart b/lib/builder/transaction_block.dart
index dbf040c..b72c94d 100644
--- a/lib/builder/transaction_block.dart
+++ b/lib/builder/transaction_block.dart
@@ -100,13 +100,13 @@ List<List<T>> chunk<T>(List<T> arr, int size) {
 
 class BuildOptions {
 	SuiClient? client;
-	bool? onlyTransactionKind;
+	bool onlyTransactionKind;
 	/// Define a protocol config to build against, instead of having it fetched from the provider at build time.
 	dynamic protocolConfig;
 	/// Define limits that are used when building the transaction. In general, we recommend using the protocol configuration instead of defining limits.
 	Limits? limits;
 
-  BuildOptions({this.client, this.onlyTransactionKind, this.protocolConfig, this.limits});
+  BuildOptions({this.client, this.onlyTransactionKind = false, this.protocolConfig, this.limits});
 }
 
 class SignOptions extends BuildOptions {
@@ -430,7 +430,7 @@ class TransactionBlock {
 		}
 
 		// Early return if the payment is already set:
-		if ((options.onlyTransactionKind ?? false) || _blockData.gasConfig.payment != null) {
+		if ((options.onlyTransactionKind) || _blockData.gasConfig.payment != null) {
 			return;
 		}
 
@@ -469,7 +469,7 @@ class TransactionBlock {
 	}
 
 	Future<void> _prepareGasPrice(BuildOptions options) async {
-		if (options.onlyTransactionKind != null || _blockData.gasConfig.price != null) {
+		if (options.onlyTransactionKind || _blockData.gasConfig.price != null) {
 			return;
 		}
 
@@ -673,7 +673,7 @@ class TransactionBlock {
 	/// Prepare the transaction by valdiating the transaction data and resolving all inputs
 	/// so that it can be built into bytes.
 	Future<void> _prepare(BuildOptions options) async {
-		if (options.onlyTransactionKind == null && _blockData.sender == null) {
+		if (options.onlyTransactionKind && _blockData.sender == null) {
 			throw ArgumentError('Missing transaction sender');
 		}
 
diff --git a/lib/builder/transaction_block_data.dart b/lib/builder/transaction_block_data.dart
index 919ab40..10ad816 100644
--- a/lib/builder/transaction_block_data.dart
+++ b/lib/builder/transaction_block_data.dart
@@ -179,7 +179,7 @@ class TransactionBlockDataBuilder {
 		String? sender,
     GasConfig? gasConfig,
     TransactionExpiration? expiration,
-		bool? onlyTransactionKind,
+		bool onlyTransactionKind = false,
 	}) {
 		// Resolve inputs down to values:
 		final inputs = this.inputs.map((input) => input["value"]);
@@ -191,7 +191,7 @@ class TransactionBlockDataBuilder {
 			},
 		};
 
-		if (onlyTransactionKind != null && onlyTransactionKind) {
+		if (onlyTransactionKind) {
       final options = BcsWriterOptions(maxSize: maxSizeBytes);
 			return builder.ser('TransactionKind', kind, options).toBytes();
 		}
diff --git a/test/sui_test.dart b/test/sui_test.dart
index b97b4c7..82fcecb 100644
--- a/test/sui_test.dart
+++ b/test/sui_test.dart
@@ -299,17 +299,14 @@ test('test programmable transaction blocks', () async {
 
     final account = SuiAccount.fromMnemonics(mnemonics, SignatureScheme.ED25519);
     final client = SuiClient(Constants.devnetAPI, account: account);
-    var coins = await client.getCoins(account.getAddress());
-    if (coins.data.isEmpty) {
+    final suiBalance = await client.getBalance(account.getAddress());
+    if (suiBalance.totalBalance == BigInt.zero) {
         final faucet = FaucetClient(Constants.faucetDevAPI);
         final resp = await faucet.requestSuiFromFaucetV0(account.getAddress());
         assert(resp.transferredGasObjects.isNotEmpty);
     }
 
-    final gasCoin = coins.data.first;
-
     final tx = TransactionBlock();
-    tx.setGasPayment([gasCoin]);
     tx.setGasBudget(BigInt.from(2000000));
 
     final coin = tx.add(Transactions.splitCoins(tx.gas, [tx.pureInt(1000)]));