ethclient/simulated: fix failing test due the min tip change

ethclient/simulated/backend_test.go

@@ -52,7 +52,7 @@ func newTx(sim *Backend, key *ecdsa.PrivateKey) (*types.Transaction, error) {
 
 	// create a signed transaction to send
 	head, _ := client.HeaderByNumber(context.Background(), nil) // Should be child's, good enough
-	gasPrice := new(big.Int).Add(head.BaseFee, big.NewInt(1))
+	gasPrice := new(big.Int).Add(head.BaseFee, big.NewInt(params.GWei))
 	addr := crypto.PubkeyToAddress(key.PublicKey)
 	chainid, _ := client.ChainID(context.Background())
 	nonce, err := client.PendingNonceAt(context.Background(), addr)
@@ -62,7 +62,7 @@ func newTx(sim *Backend, key *ecdsa.PrivateKey) (*types.Transaction, error) {
 	tx := types.NewTx(&types.DynamicFeeTx{
 		ChainID:   chainid,
 		Nonce:     nonce,
-		GasTipCap: big.NewInt(1),
+		GasTipCap: big.NewInt(params.GWei),
 		GasFeeCap: gasPrice,
 		Gas:       21000,
 		To:        &addr,

ethclient/simulated/options.go

@@ -17,6 +17,8 @@
 package simulated
 
 import (
+	"math/big"
+
 	"github.com/ethereum/go-ethereum/eth/ethconfig"
 	"github.com/ethereum/go-ethereum/node"
 )
@@ -37,3 +39,17 @@ func WithCallGasLimit(gaslimit uint64) func(nodeConf *node.Config, ethConf *ethc
 		ethConf.RPCGasCap = gaslimit
 	}
 }
+
+// WithMinerMinTip configures the simulated backend to require a specific minimum
+// gas tip for a transaction to be included.
+//
+// 0 is not possible as a live Geth node would reject that due to DoS protection,
+// so the simulated backend will replicate that behavior for consisntency.
+func WithMinerMinTip(tip *big.Int) func(nodeConf *node.Config, ethConf *ethconfig.Config) {
+	if tip == nil || tip.Cmp(new(big.Int)) <= 0 {
+		panic("invalid miner minimum tip")
+	}
+	return func(nodeConf *node.Config, ethConf *ethconfig.Config) {
+		ethConf.Miner.GasPrice = tip
+	}
+}