Add test for gas capping when creating tx message

Author: jenikd

ethapi/transaction_args_test.go

@@ -0,0 +1,75 @@
+package ethapi
+
+import (
+	"math"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGasCap(t *testing.T) {
+
+	var (
+		gas10M       = hexutil.Uint64(10_000_000)
+		gasMaxUint64 = hexutil.Uint64(math.MaxUint64)
+	)
+
+	tests := []struct {
+		name         string
+		argGas       *hexutil.Uint64
+		globalGasCap uint64
+		expectedGas  uint64
+	}{
+		{
+			name:         "gas cap 0 and arg gas nil",
+			globalGasCap: 0,
+			argGas:       nil,
+			expectedGas:  math.MaxInt64,
+		}, {
+			name:         "gas cap 0 and arg gas 10M",
+			globalGasCap: 0,
+			argGas:       &gas10M,
+			expectedGas:  10_000_000,
+		}, {
+			name:         "gas cap 0 and arg gas maxUint64",
+			globalGasCap: 0,
+			argGas:       &gasMaxUint64,
+			expectedGas:  math.MaxInt64,
+		}, {
+			name:         "gas cap 50M and arg gas nil",
+			globalGasCap: 50_000_000,
+			argGas:       nil,
+			expectedGas:  50_000_000,
+		}, {
+			name:         "gas cap 50M and arg gas 10M",
+			globalGasCap: 50_000_000,
+			argGas:       &gas10M,
+			expectedGas:  10_000_000,
+		}, {
+			name:         "gas cap 50M and arg gas maxUint64",
+			globalGasCap: 50_000_000,
+			argGas:       &gasMaxUint64,
+			expectedGas:  50_000_000,
+		}, {
+			name:         "gas cap maxUint64 and arg gas 10M",
+			globalGasCap: math.MaxUint64,
+			argGas:       &gas10M,
+			expectedGas:  10_000_000,
+		}, {
+			name:         "gas cap maxUint64 and arg gas maxUint64",
+			globalGasCap: math.MaxUint64,
+			argGas:       &gasMaxUint64,
+			expectedGas:  math.MaxInt64,
+		},
+	}
+
+	for _, test := range tests {
+		args := TransactionArgs{Gas: test.argGas}
+
+		msg, err := args.ToMessage(test.globalGasCap, nil)
+
+		require.Nil(t, err)
+		require.Equal(t, test.expectedGas, msg.GasLimit, test.name)
+	}
+}