Refactor: Move sender sanity checks into separate file with tests (#66)

Author: hazim-j

internal/testutils/opmock.go

@@ -0,0 +1,26 @@
+package testutils
+
+import "github.com/stackup-wallet/stackup-bundler/pkg/userop"
+
+var (
+	MockUserOpData = map[string]any{
+		"sender":               "0xa13D69573f994bf662C2714560c44dd7266FC547",
+		"nonce":                "0x0",
+		"initCode":             "0xe19e9755942bb0bd0cccce25b1742596b8a8250b3bf2c3e700000000000000000000000078d4f01f56b982a3b03c4e127a5d3afa8ebee6860000000000000000000000008b388a082f370d8ac2e2b3997e9151168bd09ff50000000000000000000000000000000000000000000000000000000000000000",
+		"callData":             "0x80c5c7d0000000000000000000000000a13d69573f994bf662c2714560c44dd7266fc547000000000000000000000000000000000000000000000000016345785d8a000000000000000000000000000000000000000000000000000000000000000000600000000000000000000000000000000000000000000000000000000000000000",
+		"callGasLimit":         "0x558c",
+		"verificationGasLimit": "0x129727",
+		"maxFeePerGas":         "0xa862145e",
+		"maxPriorityFeePerGas": "0xa8621440",
+		"paymasterAndData":     "0x",
+		"preVerificationGas":   "0xc650",
+		"signature":            "0xa925dcc5e5131636e244d4405334c25f034ebdd85c0cb12e8cdb13c15249c2d466d0bade18e2cafd3513497f7f968dcbb63e519acd9b76dcae7acd61f11aa8421b",
+	}
+	MockByteCode = "0x6080604052"
+)
+
+// Returns a valid initial userOperation for an EIP-4337 account.
+func MockValidInitUserOp() *userop.UserOperation {
+	op, _ := userop.New(MockUserOpData)
+	return op
+}

pkg/modules/checks/sanitychecks.go

@@ -13,23 +13,6 @@ import (
 	"github.com/stackup-wallet/stackup-bundler/pkg/userop"
 )
 
-// Checks that the sender is an existing contract, or the initCode is not empty (but not both)
-func checkSender(eth *ethclient.Client, op *userop.UserOperation) error {
-	bytecode, err := eth.CodeAt(context.Background(), op.Sender, nil)
-	if err != nil {
-		return err
-	}
-
-	if len(bytecode) == 0 && len(op.InitCode) == 0 {
-		return errors.New("sender: not deployed, initCode must be set")
-	}
-	if len(bytecode) > 0 && len(op.InitCode) > 0 {
-		return errors.New("sender: already deployed, initCode must be empty")
-	}
-
-	return nil
-}
-
 // Checks that the verificationGasLimit is sufficiently low (<= MAX_VERIFICATION_GAS) and the
 // preVerificationGas is sufficiently high (enough to pay for the calldata gas cost of serializing
 // the UserOperation plus PRE_VERIFICATION_OVERHEAD_GAS)

pkg/modules/checks/sanitychecks_test.go

@@ -0,0 +1,26 @@
+package checks
+
+import (
+	"context"
+	"errors"
+
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/stackup-wallet/stackup-bundler/pkg/userop"
+)
+
+// Checks that the sender is an existing contract, or the initCode is not empty (but not both)
+func checkSender(eth *ethclient.Client, op *userop.UserOperation) error {
+	bytecode, err := eth.CodeAt(context.Background(), op.Sender, nil)
+	if err != nil {
+		return err
+	}
+
+	if len(bytecode) == 0 && len(op.InitCode) == 0 {
+		return errors.New("sender: not deployed, initCode must be set")
+	}
+	if len(bytecode) > 0 && len(op.InitCode) > 0 {
+		return errors.New("sender: already deployed, initCode must be empty")
+	}
+
+	return nil
+}

pkg/modules/checks/sender.go

@@ -0,0 +1,70 @@
+package checks
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/stackup-wallet/stackup-bundler/internal/testutils"
+)
+
+// TestSenderExistAndInitCodeDNE calls checks.CheckSender where sender contract exist and initCode does not.
+// Expect nil.
+func TestSenderExistAndInitCodeDNE(t *testing.T) {
+	server := testutils.EthMock(testutils.MethodMocks{
+		"eth_getCode": testutils.MockByteCode,
+	})
+	defer server.Close()
+
+	eth, _ := ethclient.Dial(server.URL)
+	op := testutils.MockValidInitUserOp()
+	op.InitCode = []byte{}
+	if err := checkSender(eth, op); err != nil {
+		t.Fatalf(`got err %v, want nil`, err)
+	}
+}
+
+// TestSenderAndInitCodeExist calls checks.CheckSender where sender contract and initCode exist. Expect
+// error.
+func TestSenderAndInitCodeExist(t *testing.T) {
+	server := testutils.EthMock(testutils.MethodMocks{
+		"eth_getCode": testutils.MockByteCode,
+	})
+	defer server.Close()
+
+	eth, _ := ethclient.Dial(server.URL)
+	op := testutils.MockValidInitUserOp()
+	if err := checkSender(eth, op); err == nil {
+		t.Fatalf(`got nil, want err`)
+	}
+}
+
+// TestSenderDNEAndInitCodeExist calls checks.CheckSender where sender contract does not exist and initCode
+// does. Expect nil.
+func TestSenderDNEAndInitCodeExist(t *testing.T) {
+	server := testutils.EthMock(testutils.MethodMocks{
+		"eth_getCode": "0x",
+	})
+	defer server.Close()
+
+	eth, _ := ethclient.Dial(server.URL)
+	op := testutils.MockValidInitUserOp()
+	if err := checkSender(eth, op); err != nil {
+		t.Fatalf(`got err %v, want nil`, err)
+	}
+}
+
+// TestSenderAndInitCodeDNE calls checks.CheckSender where sender contract and initCode does not exist.
+// Expect error.
+func TestSenderAndInitCodeDNE(t *testing.T) {
+	server := testutils.EthMock(testutils.MethodMocks{
+		"eth_getCode": "0x",
+	})
+	defer server.Close()
+
+	eth, _ := ethclient.Dial(server.URL)
+	op := testutils.MockValidInitUserOp()
+	op.InitCode = []byte{}
+	if err := checkSender(eth, op); err == nil {
+		t.Fatalf(`got nil, want err`)
+	}
+}