test: tweak BNB chain test

packages/core/src/internal/execution/jsonrpc-client.ts

@@ -638,11 +638,14 @@ export class EIP1193JsonRpcClient implements JsonRpcClient {
     ]);
 
     // We prioritize EIP-1559 fees over legacy gasPrice fees, however,
-    // polygon (chainId 137) requires legacy gasPrice fees so we skip EIP-1559 logic in that case
+    // polygon (chainId 137) requires legacy gasPrice fees
+    // so we skip EIP-1559 logic in that case
     if (latestBlock.baseFeePerGas !== undefined && chainId !== 137) {
+      // Support zero gas fee chains, such as a private instances
+      // of blockchains using Besu. We explicitly exclude BNB
+      // Smartchain (chainId 56) from this logic as it is EIP-1559
+      // compliant but only sets a maxPriorityFeePerGas.
       if (latestBlock.baseFeePerGas === 0n && chainId !== 56) {
-        // Support zero gas fee chains, such as a private instances
-        // of blockchains using Besu.
         return {
           maxFeePerGas: 0n,
           maxPriorityFeePerGas: 0n,

packages/core/test-integrations/new-api/internal/new-execution/jsonrpc-client.ts

@@ -210,13 +210,13 @@ describe("JSON-RPC client", function () {
 
           const fees = await bnbClient.getNetworkFees();
 
-          assert.notDeepEqual(
+          assert.deepStrictEqual(
             fees,
             {
-              maxFeePerGas: 0n,
-              maxPriorityFeePerGas: 0n,
+              maxFeePerGas: 1_000_000_000n,
+              maxPriorityFeePerGas: 1_000_000_000n,
             },
-            "Fees should not be zero due to the specific handling for BNB Chain."
+            "Both max fee and max priority fee should be 1 gwei, as the base fee is 0 for BNB Chain"
           );
         });