aboutsummaryrefslogblamecommitdiffstats
path: root/accounts/abi/unpack_test.go
blob: fa8a69d05c77b0e97b1f1eb3a955038f75dc8b4a (plain) (tree)
1
                                         


















                                                                                  
                      


                  
                 



                                                
                                             

 





                                                      
 





                                                                                          
                 




                                                                            
 






                                                                                         
















                                                                                         











































                                                                                         




                                                                                         




























                                                                                                                                                                                                                         
                                                                                                                               



















                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         


                                                




                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         





                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         





                                                                                                                                                                                                                                                                                         




                                                                                                                                                                                                                                                                                                                                                                                                                         





















                                                                                                                                                                                                                                                                                         




                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         



















                                                                                                                                                                                                                                                                                         









                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         









                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
















































                                                                                                                                                                                                                                                                                         









                                                                                                                                                        














































                                                                                                                                                        


































                                                                                                                                                        



                                          




















                                                                                                                 


         
















































                                                                                                                                                                                                                                                                                                                                                                                          





                                                                                      

                                                                                                                                               
                                                                

                                                       
                            




                                                                                                        


                                                                     
 

                                          



                               




                                                        






















                                                                




                                                                 









                                                               





















                                                                                                   


         












                                                                                                                                                                                                                                        









                                                                      




































                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        











                                                                                                                               












                                                                                             





























                                                                                                               









                                                                      

















                                                                                                                                                         










                                                                                                                     
                       

                            
                                            


                                                                                         
                                               



                                                                                         






















                                                                                                                             
                    






























                                                                                                        
                                               


                                                                                                        
                                                            






                                                       

                                                                                 


















































                                                                                                        






















































































                                                                                                                  
 





































































































                                                                                                                                                                                                                                   




































































                                                                                                                 
// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package abi

import (
    "bytes"
    "encoding/hex"
    "fmt"
    "math/big"
    "reflect"
    "strconv"
    "strings"
    "testing"

    "github.com/ethereum/go-ethereum/common"
    "github.com/stretchr/testify/require"
)

type unpackTest struct {
    def  string      // ABI definition JSON
    enc  string      // evm return data
    want interface{} // the expected output
    err  string      // empty or error if expected
}

func (test unpackTest) checkError(err error) error {
    if err != nil {
        if len(test.err) == 0 {
            return fmt.Errorf("expected no err but got: %v", err)
        } else if err.Error() != test.err {
            return fmt.Errorf("expected err: '%v' got err: %q", test.err, err)
        }
    } else if len(test.err) > 0 {
        return fmt.Errorf("expected err: %v but got none", test.err)
    }
    return nil
}

var unpackTests = []unpackTest{
    {
        def:  `[{ "type": "bool" }]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001",
        want: true,
    },
    {
        def:  `[{ "type": "bool" }]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000000",
        want: false,
    },
    {
        def:  `[{ "type": "bool" }]`,
        enc:  "0000000000000000000000000000000000000000000000000001000000000001",
        want: false,
        err:  "abi: improperly encoded boolean value",
    },
    {
        def:  `[{ "type": "bool" }]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000003",
        want: false,
        err:  "abi: improperly encoded boolean value",
    },
    {
        def:  `[{"type": "uint32"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001",
        want: uint32(1),
    },
    {
        def:  `[{"type": "uint32"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001",
        want: uint16(0),
        err:  "abi: cannot unmarshal uint32 in to uint16",
    },
    {
        def:  `[{"type": "uint17"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001",
        want: uint16(0),
        err:  "abi: cannot unmarshal *big.Int in to uint16",
    },
    {
        def:  `[{"type": "uint17"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001",
        want: big.NewInt(1),
    },
    {
        def:  `[{"type": "int32"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001",
        want: int32(1),
    },
    {
        def:  `[{"type": "int32"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001",
        want: int16(0),
        err:  "abi: cannot unmarshal int32 in to int16",
    },
    {
        def:  `[{"type": "int17"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001",
        want: int16(0),
        err:  "abi: cannot unmarshal *big.Int in to int16",
    },
    {
        def:  `[{"type": "int17"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001",
        want: big.NewInt(1),
    },
    {
        def:  `[{"type": "int256"}]`,
        enc:  "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
        want: big.NewInt(-1),
    },
    {
        def:  `[{"type": "address"}]`,
        enc:  "0000000000000000000000000100000000000000000000000000000000000000",
        want: common.Address{1},
    },
    {
        def:  `[{"type": "bytes32"}]`,
        enc:  "0100000000000000000000000000000000000000000000000000000000000000",
        want: [32]byte{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    },
    {
        def:  `[{"type": "bytes"}]`,
        enc:  "000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000200100000000000000000000000000000000000000000000000000000000000000",
        want: common.Hex2Bytes("0100000000000000000000000000000000000000000000000000000000000000"),
    },
    {
        def:  `[{"type": "bytes"}]`,
        enc:  "000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000200100000000000000000000000000000000000000000000000000000000000000",
        want: [32]byte{},
        err:  "abi: cannot unmarshal []uint8 in to [32]uint8",
    },
    {
        def:  `[{"type": "bytes32"}]`,
        enc:  "000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000200100000000000000000000000000000000000000000000000000000000000000",
        want: []byte(nil),
        err:  "abi: cannot unmarshal [32]uint8 in to []uint8",
    },
    {
        def:  `[{"type": "bytes32"}]`,
        enc:  "0100000000000000000000000000000000000000000000000000000000000000",
        want: [32]byte{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    },
    {
        def:  `[{"type": "function"}]`,
        enc:  "0100000000000000000000000000000000000000000000000000000000000000",
        want: [24]byte{1},
    },
    // slices
    {
        def:  `[{"type": "uint8[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []uint8{1, 2},
    },
    {
        def:  `[{"type": "uint8[2]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [2]uint8{1, 2},
    },
    // multi dimensional, if these pass, all types that don't require length prefix should pass
    {
        def:  `[{"type": "uint8[][]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000a0000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [][]uint8{{1, 2}, {1, 2}},
    },
    {
        def:  `[{"type": "uint8[][]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000a00000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000003000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000003",
        want: [][]uint8{{1, 2}, {1, 2, 3}},
    },
    {
        def:  `[{"type": "uint8[2][2]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [2][2]uint8{{1, 2}, {1, 2}},
    },
    {
        def:  `[{"type": "uint8[][2]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000001",
        want: [2][]uint8{{1}, {1}},
    },
    {
        def:  `[{"type": "uint8[2][]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [][2]uint8{{1, 2}},
    },
    {
        def:  `[{"type": "uint8[2][]"}]`,
        enc:  "000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [][2]uint8{{1, 2}, {1, 2}},
    },
    {
        def:  `[{"type": "uint16[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []uint16{1, 2},
    },
    {
        def:  `[{"type": "uint16[2]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [2]uint16{1, 2},
    },
    {
        def:  `[{"type": "uint32[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []uint32{1, 2},
    },
    {
        def:  `[{"type": "uint32[2]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [2]uint32{1, 2},
    },
    {
        def:  `[{"type": "uint32[2][3][4]"}]`,
        enc:  "000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000003000000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000050000000000000000000000000000000000000000000000000000000000000006000000000000000000000000000000000000000000000000000000000000000700000000000000000000000000000000000000000000000000000000000000080000000000000000000000000000000000000000000000000000000000000009000000000000000000000000000000000000000000000000000000000000000a000000000000000000000000000000000000000000000000000000000000000b000000000000000000000000000000000000000000000000000000000000000c000000000000000000000000000000000000000000000000000000000000000d000000000000000000000000000000000000000000000000000000000000000e000000000000000000000000000000000000000000000000000000000000000f000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000110000000000000000000000000000000000000000000000000000000000000012000000000000000000000000000000000000000000000000000000000000001300000000000000000000000000000000000000000000000000000000000000140000000000000000000000000000000000000000000000000000000000000015000000000000000000000000000000000000000000000000000000000000001600000000000000000000000000000000000000000000000000000000000000170000000000000000000000000000000000000000000000000000000000000018",
        want: [4][3][2]uint32{{{1, 2}, {3, 4}, {5, 6}}, {{7, 8}, {9, 10}, {11, 12}}, {{13, 14}, {15, 16}, {17, 18}}, {{19, 20}, {21, 22}, {23, 24}}},
    },
    {
        def:  `[{"type": "uint64[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []uint64{1, 2},
    },
    {
        def:  `[{"type": "uint64[2]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [2]uint64{1, 2},
    },
    {
        def:  `[{"type": "uint256[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []*big.Int{big.NewInt(1), big.NewInt(2)},
    },
    {
        def:  `[{"type": "uint256[3]"}]`,
        enc:  "000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000003",
        want: [3]*big.Int{big.NewInt(1), big.NewInt(2), big.NewInt(3)},
    },
    {
        def:  `[{"type": "string[4]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000c000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000140000000000000000000000000000000000000000000000000000000000000000548656c6c6f0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000005576f726c64000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000b476f2d657468657265756d0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000008457468657265756d000000000000000000000000000000000000000000000000",
        want: [4]string{"Hello", "World", "Go-ethereum", "Ethereum"},
    },
    {
        def:  `[{"type": "string[]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000000008457468657265756d000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000b676f2d657468657265756d000000000000000000000000000000000000000000",
        want: []string{"Ethereum", "go-ethereum"},
    },
    {
        def:  `[{"type": "bytes[]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000000003f0f0f000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000003f0f0f00000000000000000000000000000000000000000000000000000000000",
        want: [][]byte{{0xf0, 0xf0, 0xf0}, {0xf0, 0xf0, 0xf0}},
    },
    {
        def:  `[{"type": "uint256[2][][]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000e00000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000c8000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000003e80000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000c8000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000003e8",
        want: [][][2]*big.Int{{{big.NewInt(1), big.NewInt(200)}, {big.NewInt(1), big.NewInt(1000)}}, {{big.NewInt(1), big.NewInt(200)}, {big.NewInt(1), big.NewInt(1000)}}},
    },
    {
        def:  `[{"type": "int8[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []int8{1, 2},
    },
    {
        def:  `[{"type": "int8[2]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [2]int8{1, 2},
    },
    {
        def:  `[{"type": "int16[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []int16{1, 2},
    },
    {
        def:  `[{"type": "int16[2]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [2]int16{1, 2},
    },
    {
        def:  `[{"type": "int32[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []int32{1, 2},
    },
    {
        def:  `[{"type": "int32[2]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [2]int32{1, 2},
    },
    {
        def:  `[{"type": "int64[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []int64{1, 2},
    },
    {
        def:  `[{"type": "int64[2]"}]`,
        enc:  "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: [2]int64{1, 2},
    },
    {
        def:  `[{"type": "int256[]"}]`,
        enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: []*big.Int{big.NewInt(1), big.NewInt(2)},
    },
    {
        def:  `[{"type": "int256[3]"}]`,
        enc:  "000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000003",
        want: [3]*big.Int{big.NewInt(1), big.NewInt(2), big.NewInt(3)},
    },
    // struct outputs
    {
        def: `[{"name":"int1","type":"int256"},{"name":"int2","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            Int1 *big.Int
            Int2 *big.Int
        }{big.NewInt(1), big.NewInt(2)},
    },
    {
        def: `[{"name":"int_one","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            IntOne *big.Int
        }{big.NewInt(1)},
    },
    {
        def: `[{"name":"int__one","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            IntOne *big.Int
        }{big.NewInt(1)},
    },
    {
        def: `[{"name":"int_one_","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            IntOne *big.Int
        }{big.NewInt(1)},
    },
    {
        def: `[{"name":"int_one","type":"int256"}, {"name":"intone","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            IntOne *big.Int
            Intone *big.Int
        }{big.NewInt(1), big.NewInt(2)},
    },
    {
        def: `[{"name":"___","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            IntOne *big.Int
            Intone *big.Int
        }{},
        err: "abi: purely underscored output cannot unpack to struct",
    },
    {
        def: `[{"name":"int_one","type":"int256"},{"name":"IntOne","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            Int1 *big.Int
            Int2 *big.Int
        }{},
        err: "abi: multiple outputs mapping to the same struct field 'IntOne'",
    },
    {
        def: `[{"name":"int","type":"int256"},{"name":"Int","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            Int1 *big.Int
            Int2 *big.Int
        }{},
        err: "abi: multiple outputs mapping to the same struct field 'Int'",
    },
    {
        def: `[{"name":"int","type":"int256"},{"name":"_int","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            Int1 *big.Int
            Int2 *big.Int
        }{},
        err: "abi: multiple outputs mapping to the same struct field 'Int'",
    },
    {
        def: `[{"name":"Int","type":"int256"},{"name":"_int","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            Int1 *big.Int
            Int2 *big.Int
        }{},
        err: "abi: multiple outputs mapping to the same struct field 'Int'",
    },
    {
        def: `[{"name":"Int","type":"int256"},{"name":"_","type":"int256"}]`,
        enc: "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
        want: struct {
            Int1 *big.Int
            Int2 *big.Int
        }{},
        err: "abi: purely underscored output cannot unpack to struct",
    },
}

func TestUnpack(t *testing.T) {
    for i, test := range unpackTests {
        t.Run(strconv.Itoa(i), func(t *testing.T) {
            def := fmt.Sprintf(`[{ "name" : "method", "outputs": %s}]`, test.def)
            abi, err := JSON(strings.NewReader(def))
            if err != nil {
                t.Fatalf("invalid ABI definition %s: %v", def, err)
            }
            encb, err := hex.DecodeString(test.enc)
            if err != nil {
                t.Fatalf("invalid hex: %s" + test.enc)
            }
            outptr := reflect.New(reflect.TypeOf(test.want))
            err = abi.Unpack(outptr.Interface(), "method", encb)
            if err := test.checkError(err); err != nil {
                t.Errorf("test %d (%v) failed: %v", i, test.def, err)
                return
            }
            out := outptr.Elem().Interface()
            if !reflect.DeepEqual(test.want, out) {
                t.Errorf("test %d (%v) failed: expected %v, got %v", i, test.def, test.want, out)
            }
        })
    }
}

func TestUnpackSetDynamicArrayOutput(t *testing.T) {
    abi, err := JSON(strings.NewReader(`[{"constant":true,"inputs":[],"name":"testDynamicFixedBytes15","outputs":[{"name":"","type":"bytes15[]"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"testDynamicFixedBytes32","outputs":[{"name":"","type":"bytes32[]"}],"payable":false,"stateMutability":"view","type":"function"}]`))
    if err != nil {
        t.Fatal(err)
    }

    var (
        marshalledReturn32 = common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000230783132333435363738393000000000000000000000000000000000000000003078303938373635343332310000000000000000000000000000000000000000")
        marshalledReturn15 = common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000230783031323334350000000000000000000000000000000000000000000000003078393837363534000000000000000000000000000000000000000000000000")

        out32 [][32]byte
        out15 [][15]byte
    )

    // test 32
    err = abi.Unpack(&out32, "testDynamicFixedBytes32", marshalledReturn32)
    if err != nil {
        t.Fatal(err)
    }
    if len(out32) != 2 {
        t.Fatalf("expected array with 2 values, got %d", len(out32))
    }
    expected := common.Hex2Bytes("3078313233343536373839300000000000000000000000000000000000000000")
    if !bytes.Equal(out32[0][:], expected) {
        t.Errorf("expected %x, got %x\n", expected, out32[0])
    }
    expected = common.Hex2Bytes("3078303938373635343332310000000000000000000000000000000000000000")
    if !bytes.Equal(out32[1][:], expected) {
        t.Errorf("expected %x, got %x\n", expected, out32[1])
    }

    // test 15
    err = abi.Unpack(&out15, "testDynamicFixedBytes32", marshalledReturn15)
    if err != nil {
        t.Fatal(err)
    }
    if len(out15) != 2 {
        t.Fatalf("expected array with 2 values, got %d", len(out15))
    }
    expected = common.Hex2Bytes("307830313233343500000000000000")
    if !bytes.Equal(out15[0][:], expected) {
        t.Errorf("expected %x, got %x\n", expected, out15[0])
    }
    expected = common.Hex2Bytes("307839383736353400000000000000")
    if !bytes.Equal(out15[1][:], expected) {
        t.Errorf("expected %x, got %x\n", expected, out15[1])
    }
}

type methodMultiOutput struct {
    Int    *big.Int
    String string
}

func methodMultiReturn(require *require.Assertions) (ABI, []byte, methodMultiOutput) {
    const definition = `[
    { "name" : "multi", "constant" : false, "outputs": [ { "name": "Int", "type": "uint256" }, { "name": "String", "type": "string" } ] }]`
    var expected = methodMultiOutput{big.NewInt(1), "hello"}

    abi, err := JSON(strings.NewReader(definition))
    require.NoError(err)
    // using buff to make the code readable
    buff := new(bytes.Buffer)
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000040"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000005"))
    buff.Write(common.RightPadBytes([]byte(expected.String), 32))
    return abi, buff.Bytes(), expected
}

func TestMethodMultiReturn(t *testing.T) {
    type reversed struct {
        String string
        Int    *big.Int
    }

    newInterfaceSlice := func(len int) interface{} {
        slice := make([]interface{}, len)
        return &slice
    }

    abi, data, expected := methodMultiReturn(require.New(t))
    bigint := new(big.Int)
    var testCases = []struct {
        dest     interface{}
        expected interface{}
        error    string
        name     string
    }{{
        &methodMultiOutput{},
        &expected,
        "",
        "Can unpack into structure",
    }, {
        &reversed{},
        &reversed{expected.String, expected.Int},
        "",
        "Can unpack into reversed structure",
    }, {
        &[]interface{}{&bigint, new(string)},
        &[]interface{}{&expected.Int, &expected.String},
        "",
        "Can unpack into a slice",
    }, {
        &[2]interface{}{&bigint, new(string)},
        &[2]interface{}{&expected.Int, &expected.String},
        "",
        "Can unpack into an array",
    }, {
        &[2]interface{}{},
        &[2]interface{}{expected.Int, expected.String},
        "",
        "Can unpack into interface array",
    }, {
        newInterfaceSlice(2),
        &[]interface{}{expected.Int, expected.String},
        "",
        "Can unpack into interface slice",
    }, {
        &[]interface{}{new(int), new(int)},
        &[]interface{}{&expected.Int, &expected.String},
        "abi: cannot unmarshal *big.Int in to int",
        "Can not unpack into a slice with wrong types",
    }, {
        &[]interface{}{new(int)},
        &[]interface{}{},
        "abi: insufficient number of elements in the list/array for unpack, want 2, got 1",
        "Can not unpack into a slice with wrong types",
    }}
    for _, tc := range testCases {
        tc := tc
        t.Run(tc.name, func(t *testing.T) {
            require := require.New(t)
            err := abi.Unpack(tc.dest, "multi", data)
            if tc.error == "" {
                require.Nil(err, "Should be able to unpack method outputs.")
                require.Equal(tc.expected, tc.dest)
            } else {
                require.EqualError(err, tc.error)
            }
        })
    }
}

func TestMultiReturnWithArray(t *testing.T) {
    const definition = `[{"name" : "multi", "outputs": [{"type": "uint64[3]"}, {"type": "uint64"}]}]`
    abi, err := JSON(strings.NewReader(definition))
    if err != nil {
        t.Fatal(err)
    }
    buff := new(bytes.Buffer)
    buff.Write(common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000900000000000000000000000000000000000000000000000000000000000000090000000000000000000000000000000000000000000000000000000000000009"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000008"))

    ret1, ret1Exp := new([3]uint64), [3]uint64{9, 9, 9}
    ret2, ret2Exp := new(uint64), uint64(8)
    if err := abi.Unpack(&[]interface{}{ret1, ret2}, "multi", buff.Bytes()); err != nil {
        t.Fatal(err)
    }
    if !reflect.DeepEqual(*ret1, ret1Exp) {
        t.Error("array result", *ret1, "!= Expected", ret1Exp)
    }
    if *ret2 != ret2Exp {
        t.Error("int result", *ret2, "!= Expected", ret2Exp)
    }
}

func TestMultiReturnWithStringArray(t *testing.T) {
    const definition = `[{"name" : "multi", "outputs": [{"name": "","type": "uint256[3]"},{"name": "","type": "address"},{"name": "","type": "string[2]"},{"name": "","type": "bool"}]}]`
    abi, err := JSON(strings.NewReader(definition))
    if err != nil {
        t.Fatal(err)
    }
    buff := new(bytes.Buffer)
    buff.Write(common.Hex2Bytes("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"))
    temp, _ := big.NewInt(0).SetString("30000000000000000000", 10)
    ret1, ret1Exp := new([3]*big.Int), [3]*big.Int{big.NewInt(1545304298), big.NewInt(6), temp}
    ret2, ret2Exp := new(common.Address), common.HexToAddress("ab1257528b3782fb40d7ed5f72e624b744dffb2f")
    ret3, ret3Exp := new([2]string), [2]string{"Ethereum", "Hello, Ethereum!"}
    ret4, ret4Exp := new(bool), false
    if err := abi.Unpack(&[]interface{}{ret1, ret2, ret3, ret4}, "multi", buff.Bytes()); err != nil {
        t.Fatal(err)
    }
    if !reflect.DeepEqual(*ret1, ret1Exp) {
        t.Error("big.Int array result", *ret1, "!= Expected", ret1Exp)
    }
    if !reflect.DeepEqual(*ret2, ret2Exp) {
        t.Error("address result", *ret2, "!= Expected", ret2Exp)
    }
    if !reflect.DeepEqual(*ret3, ret3Exp) {
        t.Error("string array result", *ret3, "!= Expected", ret3Exp)
    }
    if !reflect.DeepEqual(*ret4, ret4Exp) {
        t.Error("bool result", *ret4, "!= Expected", ret4Exp)
    }
}

func TestMultiReturnWithStringSlice(t *testing.T) {
    const definition = `[{"name" : "multi", "outputs": [{"name": "","type": "string[]"},{"name": "","type": "uint256[]"}]}]`
    abi, err := JSON(strings.NewReader(definition))
    if err != nil {
        t.Fatal(err)
    }
    buff := new(bytes.Buffer)
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000040")) // output[0] offset
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000120")) // output[1] offset
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002")) // output[0] length
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000040")) // output[0][0] offset
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000080")) // output[0][1] offset
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000008")) // output[0][0] length
    buff.Write(common.Hex2Bytes("657468657265756d000000000000000000000000000000000000000000000000")) // output[0][0] value
    buff.Write(common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000b")) // output[0][1] length
    buff.Write(common.Hex2Bytes("676f2d657468657265756d000000000000000000000000000000000000000000")) // output[0][1] value
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002")) // output[1] length
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000064")) // output[1][0] value
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000065")) // output[1][1] value
    ret1, ret1Exp := new([]string), []string{"ethereum", "go-ethereum"}
    ret2, ret2Exp := new([]*big.Int), []*big.Int{big.NewInt(100), big.NewInt(101)}
    if err := abi.Unpack(&[]interface{}{ret1, ret2}, "multi", buff.Bytes()); err != nil {
        t.Fatal(err)
    }
    if !reflect.DeepEqual(*ret1, ret1Exp) {
        t.Error("string slice result", *ret1, "!= Expected", ret1Exp)
    }
    if !reflect.DeepEqual(*ret2, ret2Exp) {
        t.Error("uint256 slice result", *ret2, "!= Expected", ret2Exp)
    }
}

func TestMultiReturnWithDeeplyNestedArray(t *testing.T) {
    // Similar to TestMultiReturnWithArray, but with a special case in mind:
    //  values of nested static arrays count towards the size as well, and any element following
    //  after such nested array argument should be read with the correct offset,
    //  so that it does not read content from the previous array argument.
    const definition = `[{"name" : "multi", "outputs": [{"type": "uint64[3][2][4]"}, {"type": "uint64"}]}]`
    abi, err := JSON(strings.NewReader(definition))
    if err != nil {
        t.Fatal(err)
    }
    buff := new(bytes.Buffer)
    // construct the test array, each 3 char element is joined with 61 '0' chars,
    // to from the ((3 + 61) * 0.5) = 32 byte elements in the array.
    buff.Write(common.Hex2Bytes(strings.Join([]string{
        "", //empty, to apply the 61-char separator to the first element as well.
        "111", "112", "113", "121", "122", "123",
        "211", "212", "213", "221", "222", "223",
        "311", "312", "313", "321", "322", "323",
        "411", "412", "413", "421", "422", "423",
    }, "0000000000000000000000000000000000000000000000000000000000000")))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000009876"))

    ret1, ret1Exp := new([4][2][3]uint64), [4][2][3]uint64{
        {{0x111, 0x112, 0x113}, {0x121, 0x122, 0x123}},
        {{0x211, 0x212, 0x213}, {0x221, 0x222, 0x223}},
        {{0x311, 0x312, 0x313}, {0x321, 0x322, 0x323}},
        {{0x411, 0x412, 0x413}, {0x421, 0x422, 0x423}},
    }
    ret2, ret2Exp := new(uint64), uint64(0x9876)
    if err := abi.Unpack(&[]interface{}{ret1, ret2}, "multi", buff.Bytes()); err != nil {
        t.Fatal(err)
    }
    if !reflect.DeepEqual(*ret1, ret1Exp) {
        t.Error("array result", *ret1, "!= Expected", ret1Exp)
    }
    if *ret2 != ret2Exp {
        t.Error("int result", *ret2, "!= Expected", ret2Exp)
    }
}

func TestUnmarshal(t *testing.T) {
    const definition = `[
    { "name" : "int", "constant" : false, "outputs": [ { "type": "uint256" } ] },
    { "name" : "bool", "constant" : false, "outputs": [ { "type": "bool" } ] },
    { "name" : "bytes", "constant" : false, "outputs": [ { "type": "bytes" } ] },
    { "name" : "fixed", "constant" : false, "outputs": [ { "type": "bytes32" } ] },
    { "name" : "multi", "constant" : false, "outputs": [ { "type": "bytes" }, { "type": "bytes" } ] },
    { "name" : "intArraySingle", "constant" : false, "outputs": [ { "type": "uint256[3]" } ] },
    { "name" : "addressSliceSingle", "constant" : false, "outputs": [ { "type": "address[]" } ] },
    { "name" : "addressSliceDouble", "constant" : false, "outputs": [ { "name": "a", "type": "address[]" }, { "name": "b", "type": "address[]" } ] },
    { "name" : "mixedBytes", "constant" : true, "outputs": [ { "name": "a", "type": "bytes" }, { "name": "b", "type": "bytes32" } ] }]`

    abi, err := JSON(strings.NewReader(definition))
    if err != nil {
        t.Fatal(err)
    }
    buff := new(bytes.Buffer)

    // marshall mixed bytes (mixedBytes)
    p0, p0Exp := []byte{}, common.Hex2Bytes("01020000000000000000")
    p1, p1Exp := [32]byte{}, common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000ddeeff")
    mixedBytes := []interface{}{&p0, &p1}

    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000040"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000ddeeff"))
    buff.Write(common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000a"))
    buff.Write(common.Hex2Bytes("0102000000000000000000000000000000000000000000000000000000000000"))

    err = abi.Unpack(&mixedBytes, "mixedBytes", buff.Bytes())
    if err != nil {
        t.Error(err)
    } else {
        if !bytes.Equal(p0, p0Exp) {
            t.Errorf("unexpected value unpacked: want %x, got %x", p0Exp, p0)
        }

        if !bytes.Equal(p1[:], p1Exp) {
            t.Errorf("unexpected value unpacked: want %x, got %x", p1Exp, p1)
        }
    }

    // marshal int
    var Int *big.Int
    err = abi.Unpack(&Int, "int", common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001"))
    if err != nil {
        t.Error(err)
    }

    if Int == nil || Int.Cmp(big.NewInt(1)) != 0 {
        t.Error("expected Int to be 1 got", Int)
    }

    // marshal bool
    var Bool bool
    err = abi.Unpack(&Bool, "bool", common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001"))
    if err != nil {
        t.Error(err)
    }

    if !Bool {
        t.Error("expected Bool to be true")
    }

    // marshal dynamic bytes max length 32
    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020"))
    bytesOut := common.RightPadBytes([]byte("hello"), 32)
    buff.Write(bytesOut)

    var Bytes []byte
    err = abi.Unpack(&Bytes, "bytes", buff.Bytes())
    if err != nil {
        t.Error(err)
    }

    if !bytes.Equal(Bytes, bytesOut) {
        t.Errorf("expected %x got %x", bytesOut, Bytes)
    }

    // marshall dynamic bytes max length 64
    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000040"))
    bytesOut = common.RightPadBytes([]byte("hello"), 64)
    buff.Write(bytesOut)

    err = abi.Unpack(&Bytes, "bytes", buff.Bytes())
    if err != nil {
        t.Error(err)
    }

    if !bytes.Equal(Bytes, bytesOut) {
        t.Errorf("expected %x got %x", bytesOut, Bytes)
    }

    // marshall dynamic bytes max length 64
    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020"))
    buff.Write(common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000003f"))
    bytesOut = common.RightPadBytes([]byte("hello"), 64)
    buff.Write(bytesOut)

    err = abi.Unpack(&Bytes, "bytes", buff.Bytes())
    if err != nil {
        t.Error(err)
    }

    if !bytes.Equal(Bytes, bytesOut[:len(bytesOut)-1]) {
        t.Errorf("expected %x got %x", bytesOut[:len(bytesOut)-1], Bytes)
    }

    // marshal dynamic bytes output empty
    err = abi.Unpack(&Bytes, "bytes", nil)
    if err == nil {
        t.Error("expected error")
    }

    // marshal dynamic bytes length 5
    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000005"))
    buff.Write(common.RightPadBytes([]byte("hello"), 32))

    err = abi.Unpack(&Bytes, "bytes", buff.Bytes())
    if err != nil {
        t.Error(err)
    }

    if !bytes.Equal(Bytes, []byte("hello")) {
        t.Errorf("expected %x got %x", bytesOut, Bytes)
    }

    // marshal dynamic bytes length 5
    buff.Reset()
    buff.Write(common.RightPadBytes([]byte("hello"), 32))

    var hash common.Hash
    err = abi.Unpack(&hash, "fixed", buff.Bytes())
    if err != nil {
        t.Error(err)
    }

    helloHash := common.BytesToHash(common.RightPadBytes([]byte("hello"), 32))
    if hash != helloHash {
        t.Errorf("Expected %x to equal %x", hash, helloHash)
    }

    // marshal error
    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020"))
    err = abi.Unpack(&Bytes, "bytes", buff.Bytes())
    if err == nil {
        t.Error("expected error")
    }

    err = abi.Unpack(&Bytes, "multi", make([]byte, 64))
    if err == nil {
        t.Error("expected error")
    }

    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000003"))
    // marshal int array
    var intArray [3]*big.Int
    err = abi.Unpack(&intArray, "intArraySingle", buff.Bytes())
    if err != nil {
        t.Error(err)
    }
    var testAgainstIntArray [3]*big.Int
    testAgainstIntArray[0] = big.NewInt(1)
    testAgainstIntArray[1] = big.NewInt(2)
    testAgainstIntArray[2] = big.NewInt(3)

    for i, Int := range intArray {
        if Int.Cmp(testAgainstIntArray[i]) != 0 {
            t.Errorf("expected %v, got %v", testAgainstIntArray[i], Int)
        }
    }
    // marshal address slice
    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020")) // offset
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001")) // size
    buff.Write(common.Hex2Bytes("0000000000000000000000000100000000000000000000000000000000000000"))

    var outAddr []common.Address
    err = abi.Unpack(&outAddr, "addressSliceSingle", buff.Bytes())
    if err != nil {
        t.Fatal("didn't expect error:", err)
    }

    if len(outAddr) != 1 {
        t.Fatal("expected 1 item, got", len(outAddr))
    }

    if outAddr[0] != (common.Address{1}) {
        t.Errorf("expected %x, got %x", common.Address{1}, outAddr[0])
    }

    // marshal multiple address slice
    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000040")) // offset
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000080")) // offset
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001")) // size
    buff.Write(common.Hex2Bytes("0000000000000000000000000100000000000000000000000000000000000000"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002")) // size
    buff.Write(common.Hex2Bytes("0000000000000000000000000200000000000000000000000000000000000000"))
    buff.Write(common.Hex2Bytes("0000000000000000000000000300000000000000000000000000000000000000"))

    var outAddrStruct struct {
        A []common.Address
        B []common.Address
    }
    err = abi.Unpack(&outAddrStruct, "addressSliceDouble", buff.Bytes())
    if err != nil {
        t.Fatal("didn't expect error:", err)
    }

    if len(outAddrStruct.A) != 1 {
        t.Fatal("expected 1 item, got", len(outAddrStruct.A))
    }

    if outAddrStruct.A[0] != (common.Address{1}) {
        t.Errorf("expected %x, got %x", common.Address{1}, outAddrStruct.A[0])
    }

    if len(outAddrStruct.B) != 2 {
        t.Fatal("expected 1 item, got", len(outAddrStruct.B))
    }

    if outAddrStruct.B[0] != (common.Address{2}) {
        t.Errorf("expected %x, got %x", common.Address{2}, outAddrStruct.B[0])
    }
    if outAddrStruct.B[1] != (common.Address{3}) {
        t.Errorf("expected %x, got %x", common.Address{3}, outAddrStruct.B[1])
    }

    // marshal invalid address slice
    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000100"))

    err = abi.Unpack(&outAddr, "addressSliceSingle", buff.Bytes())
    if err == nil {
        t.Fatal("expected error:", err)
    }
}

func TestUnpackTuple(t *testing.T) {
    const simpleTuple = `[{"name":"tuple","constant":false,"outputs":[{"type":"tuple","name":"ret","components":[{"type":"int256","name":"a"},{"type":"int256","name":"b"}]}]}]`
    abi, err := JSON(strings.NewReader(simpleTuple))
    if err != nil {
        t.Fatal(err)
    }
    buff := new(bytes.Buffer)

    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001")) // ret[a] = 1
    buff.Write(common.Hex2Bytes("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff")) // ret[b] = -1

    v := struct {
        Ret struct {
            A *big.Int
            B *big.Int
        }
    }{Ret: struct {
        A *big.Int
        B *big.Int
    }{new(big.Int), new(big.Int)}}

    err = abi.Unpack(&v, "tuple", buff.Bytes())
    if err != nil {
        t.Error(err)
    } else {
        if v.Ret.A.Cmp(big.NewInt(1)) != 0 {
            t.Errorf("unexpected value unpacked: want %x, got %x", 1, v.Ret.A)
        }
        if v.Ret.B.Cmp(big.NewInt(-1)) != 0 {
            t.Errorf("unexpected value unpacked: want %x, got %x", v.Ret.B, -1)
        }
    }

    // Test nested tuple
    const nestedTuple = `[{"name":"tuple","constant":false,"outputs":[
        {"type":"tuple","name":"s","components":[{"type":"uint256","name":"a"},{"type":"uint256[]","name":"b"},{"type":"tuple[]","name":"c","components":[{"name":"x", "type":"uint256"},{"name":"y","type":"uint256"}]}]},
        {"type":"tuple","name":"t","components":[{"name":"x", "type":"uint256"},{"name":"y","type":"uint256"}]},
        {"type":"uint256","name":"a"}
    ]}]`

    abi, err = JSON(strings.NewReader(nestedTuple))
    if err != nil {
        t.Fatal(err)
    }
    buff.Reset()
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000080")) // s offset
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000000")) // t.X = 0
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001")) // t.Y = 1
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001")) // a = 1
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001")) // s.A = 1
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000060")) // s.B offset
    buff.Write(common.Hex2Bytes("00000000000000000000000000000000000000000000000000000000000000c0")) // s.C offset
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002")) // s.B length
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001")) // s.B[0] = 1
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002")) // s.B[0] = 2
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002")) // s.C length
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001")) // s.C[0].X
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002")) // s.C[0].Y
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002")) // s.C[1].X
    buff.Write(common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000001")) // s.C[1].Y

    type T struct {
        X *big.Int `abi:"x"`
        Z *big.Int `abi:"y"` // Test whether the abi tag works.
    }

    type S struct {
        A *big.Int
        B []*big.Int
        C []T
    }

    type Ret struct {
        FieldS S `abi:"s"`
        FieldT T `abi:"t"`
        A      *big.Int
    }
    var ret Ret
    var expected = Ret{
        FieldS: S{
            A: big.NewInt(1),
            B: []*big.Int{big.NewInt(1), big.NewInt(2)},
            C: []T{
                {big.NewInt(1), big.NewInt(2)},
                {big.NewInt(2), big.NewInt(1)},
            },
        },
        FieldT: T{
            big.NewInt(0), big.NewInt(1),
        },
        A: big.NewInt(1),
    }

    err = abi.Unpack(&ret, "tuple", buff.Bytes())
    if err != nil {
        t.Error(err)
    }
    if reflect.DeepEqual(ret, expected) {
        t.Error("unexpected unpack value")
    }
}

func TestOOMMaliciousInput(t *testing.T) {
    oomTests := []unpackTest{
        {
            def: `[{"type": "uint8[]"}]`,
            enc: "0000000000000000000000000000000000000000000000000000000000000020" + // offset
                "0000000000000000000000000000000000000000000000000000000000000003" + // num elems
                "0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
                "0000000000000000000000000000000000000000000000000000000000000002", // elem 2
        },
        { // Length larger than 64 bits
            def: `[{"type": "uint8[]"}]`,
            enc: "0000000000000000000000000000000000000000000000000000000000000020" + // offset
                "00ffffffffffffffffffffffffffffffffffffffffffffff0000000000000002" + // num elems
                "0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
                "0000000000000000000000000000000000000000000000000000000000000002", // elem 2
        },
        { // Offset very large (over 64 bits)
            def: `[{"type": "uint8[]"}]`,
            enc: "00ffffffffffffffffffffffffffffffffffffffffffffff0000000000000020" + // offset
                "0000000000000000000000000000000000000000000000000000000000000002" + // num elems
                "0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
                "0000000000000000000000000000000000000000000000000000000000000002", // elem 2
        },
        { // Offset very large (below 64 bits)
            def: `[{"type": "uint8[]"}]`,
            enc: "0000000000000000000000000000000000000000000000007ffffffffff00020" + // offset
                "0000000000000000000000000000000000000000000000000000000000000002" + // num elems
                "0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
                "0000000000000000000000000000000000000000000000000000000000000002", // elem 2
        },
        { // Offset negative (as 64 bit)
            def: `[{"type": "uint8[]"}]`,
            enc: "000000000000000000000000000000000000000000000000f000000000000020" + // offset
                "0000000000000000000000000000000000000000000000000000000000000002" + // num elems
                "0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
                "0000000000000000000000000000000000000000000000000000000000000002", // elem 2
        },

        { // Negative length
            def: `[{"type": "uint8[]"}]`,
            enc: "0000000000000000000000000000000000000000000000000000000000000020" + // offset
                "000000000000000000000000000000000000000000000000f000000000000002" + // num elems
                "0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
                "0000000000000000000000000000000000000000000000000000000000000002", // elem 2
        },
        { // Very large length
            def: `[{"type": "uint8[]"}]`,
            enc: "0000000000000000000000000000000000000000000000000000000000000020" + // offset
                "0000000000000000000000000000000000000000000000007fffffffff000002" + // num elems
                "0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
                "0000000000000000000000000000000000000000000000000000000000000002", // elem 2
        },
    }
    for i, test := range oomTests {
        def := fmt.Sprintf(`[{ "name" : "method", "outputs": %s}]`, test.def)
        abi, err := JSON(strings.NewReader(def))
        if err != nil {
            t.Fatalf("invalid ABI definition %s: %v", def, err)
        }
        encb, err := hex.DecodeString(test.enc)
        if err != nil {
            t.Fatalf("invalid hex: %s" + test.enc)
        }
        _, err = abi.Methods["method"].Outputs.UnpackValues(encb)
        if err == nil {
            t.Fatalf("Expected error on malicious input, test %d", i)
        }
    }
}