Added GasTipCap method (#89)

* Added GasTipCap method

* update `GasTipCap` doc

* test fixes

---------

Co-authored-by: lmittmann <3458786+lmittmann@users.noreply.github.com>
Signed-off-by: Mohammed Sohail <sohailsameja@gmail.com>

README.md

@@ -208,6 +208,7 @@ List of supported RPC methods.
 | `eth_createAccessList`                    | `eth.AccessList(msg *w3types.Message, blockNumber *big.Int).Returns(resp *eth.AccessListResponse)`
 | `eth_estimateGas`                         | `eth.EstimateGas(msg *w3types.Message, blockNumber *big.Int).Returns(gas *uint64)`
 | `eth_gasPrice`                            | `eth.GasPrice().Returns(gasPrice *big.Int)`
+| `eth_maxPriorityFeePerGas`                | `eth.GasTipCap().Returns(gasTipCap *big.Int)`
 | `eth_getBalance`                          | `eth.Balance(addr common.Address, blockNumber *big.Int).Returns(balance *big.Int)`
 | `eth_getBlockByHash`                      | `eth.BlockByHash(hash common.Hash).Returns(block *types.Block)`<br>`eth.HeaderByHash(hash common.Hash).Returns(header *types.Header)`
 | `eth_getBlockByNumber`                    | `eth.BlockByNumber(number *big.Int).Returns(block *types.Block)`<br>`eth.HeaderByNumber(number *big.Int).Returns(header *types.Header)`

module/eth/gas_tip_cap.go

@@ -0,0 +1,18 @@
+package eth
+
+import (
+	"math/big"
+
+	"github.com/lmittmann/w3/internal/module"
+	"github.com/lmittmann/w3/w3types"
+)
+
+// GasTipCap requests the currently suggested gas tip cap after EIP-1559 to
+// allow a timely execution of a transaction.
+func GasTipCap() w3types.CallerFactory[big.Int] {
+	return module.NewFactory(
+		"eth_maxPriorityFeePerGas",
+		nil,
+		module.WithRetWrapper(module.HexBigRetWrapper),
+	)
+}

module/eth/gas_tip_cap_test.go

@@ -0,0 +1,22 @@
+package eth_test
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/lmittmann/w3"
+	"github.com/lmittmann/w3/module/eth"
+	"github.com/lmittmann/w3/rpctest"
+)
+
+func TestGasTipCap(t *testing.T) {
+	tests := []rpctest.TestCase[big.Int]{
+		{
+			Golden:  "gas_tip_cap",
+			Call:    eth.GasTipCap(),
+			WantRet: *w3.I("0xc0fe"),
+		},
+	}
+
+	rpctest.RunTestCases(t, tests)
+}

module/eth/testdata/gas_tip_cap.golden

@@ -0,0 +1,2 @@
+> {"jsonrpc":"2.0","id":1,"method":"eth_maxPriorityFeePerGas"}
+< {"jsonrpc":"2.0","id":1,"result":"0xc0fe"}