fix(loadtest): update gas price logic in runner

loadtest/runner.go

@@ -1544,10 +1544,6 @@ func (r *Runner) suggestMaxFeePerGas(ctx context.Context, blockNumber uint64, fo
 		return nil
 	}
 
-	if r.cachedBlockNumber != nil && blockNumber <= *r.cachedBlockNumber && r.cachedGasPrice != nil {
-		return r.cachedGasPrice
-	}
-
 	feeHistory, err := r.client.FeeHistory(ctx, 5, nil, []float64{0.5})
 	if err != nil {
 		log.Error().Err(err).Msg("Unable to get fee history while checking MaxFeePerGas")
@@ -1563,13 +1559,6 @@ func (r *Runner) suggestMaxFeePerGas(ctx context.Context, blockNumber uint64, fo
 	maxFeePerGas.Mul(baseFee, big.NewInt(2))
 	maxFeePerGas.Add(maxFeePerGas, priorityFee)
 
-	const blocksToWait = 5
-	isDecreasing := r.cachedGasPrice != nil && maxFeePerGas.Uint64() <= r.cachedGasPrice.Uint64()
-	canDecrease := blockNumber+blocksToWait <= header.Number.Uint64()
-	if isDecreasing && !canDecrease && r.cachedGasPrice != nil {
-		return r.cachedGasPrice
-	}
-
 	r.cachedGasPrice = maxFeePerGas
 
 	log.Trace().

loadtest/runner_gas_test.go

@@ -0,0 +1,78 @@
+package loadtest
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"math/big"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/0xPolygon/polygon-cli/loadtest/config"
+	"github.com/ethereum/go-ethereum/ethclient"
+)
+
+type rpcReq struct {
+	Method string `json:"method"`
+	ID     int    `json:"id"`
+}
+
+func TestRunnerGasPriceDecrease(t *testing.T) {
+	var baseFee int64 = 100
+	var blockNum uint64 = 1000
+
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var req rpcReq
+		json.NewDecoder(r.Body).Decode(&req)
+		w.Header().Set("Content-Type", "application/json")
+		switch req.Method {
+		case "eth_blockNumber":
+			fmt.Fprintf(w, `{"jsonrpc":"2.0","id":%d,"result":"0x%x"}`, req.ID, blockNum)
+		case "eth_getBlockByNumber":
+			fmt.Fprintf(w, `{"jsonrpc":"2.0","id":%d,"result":{"number":"0x%x","baseFeePerGas":"0x%x","parentHash":"0x0000000000000000000000000000000000000000000000000000000000000000","difficulty":"0x0","extraData":"0x","gasLimit":"0x0","gasUsed":"0x0","miner":"0x0000000000000000000000000000000000000000","mixHash":"0x0000000000000000000000000000000000000000000000000000000000000000","nonce":"0x0000000000000000","receiptsRoot":"0x0000000000000000000000000000000000000000000000000000000000000000","sha3Uncles":"0x0000000000000000000000000000000000000000000000000000000000000000","stateRoot":"0x0000000000000000000000000000000000000000000000000000000000000000","timestamp":"0x0","transactionsRoot":"0x0000000000000000000000000000000000000000000000000000000000000000","logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"}}`, req.ID, blockNum, baseFee)
+		case "eth_feeHistory":
+			// Return a fee history where the latest base fee is our current baseFee
+			fmt.Fprintf(w, `{"jsonrpc":"2.0","id":%d,"result":{"baseFeePerGas":["0x%x","0x%x"],"reward":[["0x%x"]]}}`, req.ID, baseFee, baseFee, 10)
+		case "eth_maxPriorityFeePerGas":
+			fmt.Fprintf(w, `{"jsonrpc":"2.0","id":%d,"result":"0xa"}`, req.ID)
+		case "eth_chainId":
+			fmt.Fprintf(w, `{"jsonrpc":"2.0","id":%d,"result":"0x89"}`, req.ID)
+		default:
+			fmt.Fprintf(w, `{"jsonrpc":"2.0","id":%d,"result":"0x0"}`, req.ID)
+		}
+	}))
+	defer ts.Close()
+
+	client, _ := ethclient.Dial(ts.URL)
+	r := &Runner{
+		cfg: &config.Config{
+			ChainSupportBaseFee:   true,
+			BigGasPriceMultiplier: big.NewFloat(1.0),
+		},
+		client: client,
+	}
+
+	ctx := context.Background()
+
+	// 1. Initial price
+	gp1, _ := r.getSuggestedGasPrices(ctx)
+	// baseFee 100 * 2 + priority 10 = 210
+	if gp1.Int64() != 210 {
+		t.Errorf("Expected 210, got %v", gp1)
+	}
+
+	// 2. Decrease base fee and advance block
+	baseFee = 50
+	blockNum = 1001
+	// Reset the cache to force a new fetch
+	r.cachedLatestBlockTime = time.Time{}
+
+	gp2, _ := r.getSuggestedGasPrices(ctx)
+	// new baseFee 50 * 2 + priority 10 = 110
+	// Before the fix, this would have returned 210 because of the broken blocksToWait logic.
+	if gp2.Int64() != 110 {
+		t.Errorf("Expected 110, got %v", gp2)
+	}
+}