package vm

import (
	"bytes"
	"encoding/binary"
	"encoding/hex"
	"math/big"
	"math/rand"
	"testing"

	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
	"github.com/CityOfZion/neo-go/pkg/crypto/keys"
	"github.com/CityOfZion/neo-go/pkg/util"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestInteropHook(t *testing.T) {
	v := New()
	v.RegisterInteropFunc("foo", func(evm *VM) error {
		evm.Estack().PushVal(1)
		return nil
	}, 1)

	buf := new(bytes.Buffer)
	EmitSyscall(buf, "foo")
	EmitOpcode(buf, RET)
	v.Load(buf.Bytes())
	runVM(t, v)
	assert.Equal(t, 1, v.estack.Len())
	assert.Equal(t, big.NewInt(1), v.estack.Pop().value.Value())
}

func TestRegisterInterop(t *testing.T) {
	v := New()
	currRegistered := len(v.interop)
	v.RegisterInteropFunc("foo", func(evm *VM) error { return nil }, 1)
	assert.Equal(t, currRegistered+1, len(v.interop))
	_, ok := v.interop["foo"]
	assert.Equal(t, true, ok)
}

func TestPushBytes1to75(t *testing.T) {
	buf := new(bytes.Buffer)
	for i := 1; i <= 75; i++ {
		b := randomBytes(i)
		EmitBytes(buf, b)
		vm := load(buf.Bytes())
		err := vm.Step()
		require.NoError(t, err)

		assert.Equal(t, 1, vm.estack.Len())

		elem := vm.estack.Pop()
		assert.IsType(t, &ByteArrayItem{}, elem.value)
		assert.IsType(t, elem.Bytes(), b)
		assert.Equal(t, 0, vm.estack.Len())

		errExec := vm.execute(nil, RET, nil)
		require.NoError(t, errExec)

		assert.Equal(t, 0, vm.astack.Len())
		assert.Equal(t, 0, vm.istack.Len())
		buf.Reset()
	}
}

func TestPushBytesNoParam(t *testing.T) {
	prog := make([]byte, 1)
	prog[0] = byte(PUSHBYTES1)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func runVM(t *testing.T, vm *VM) {
	err := vm.Run()
	require.NoError(t, err)
	assert.Equal(t, false, vm.HasFailed())
}

func checkVMFailed(t *testing.T, vm *VM) {
	err := vm.Run()
	require.Error(t, err)
	assert.Equal(t, true, vm.HasFailed())
}

func TestStackLimitPUSH1Good(t *testing.T) {
	prog := make([]byte, MaxStackSize*2)
	for i := 0; i < MaxStackSize; i++ {
		prog[i] = byte(PUSH1)
	}
	for i := MaxStackSize; i < MaxStackSize*2; i++ {
		prog[i] = byte(DROP)
	}

	v := load(prog)
	runVM(t, v)
}

func TestStackLimitPUSH1Bad(t *testing.T) {
	prog := make([]byte, MaxStackSize+1)
	for i := range prog {
		prog[i] = byte(PUSH1)
	}
	v := load(prog)
	checkVMFailed(t, v)
}

// appendBigStruct returns a program which:
// 1. pushes size Structs on stack
// 2. packs them into a new struct
// 3. appends them to a zero-length array
// Resulting stack size consists of:
// - struct (size+1)
// - array (1) of struct (size+1)
// which equals to size*2+3 elements in total.
func appendBigStruct(size uint16) []Instruction {
	prog := make([]Instruction, size*2)
	for i := uint16(0); i < size; i++ {
		prog[i*2] = PUSH0
		prog[i*2+1] = NEWSTRUCT
	}

	return append(prog,
		PUSHBYTES2, Instruction(size), Instruction(size>>8), // LE
		PACK, NEWSTRUCT,
		DUP,
		PUSH0, NEWARRAY, TOALTSTACK, DUPFROMALTSTACK,
		SWAP,
		APPEND, RET)
}

func TestStackLimitAPPENDStructGood(t *testing.T) {
	prog := makeProgram(appendBigStruct(MaxStackSize/2 - 2)...)
	v := load(prog)
	runVM(t, v) // size = 2047 = (Max/2-2)*2+3 = Max-1
}

func TestStackLimitAPPENDStructBad(t *testing.T) {
	prog := makeProgram(appendBigStruct(MaxStackSize/2 - 1)...)
	v := load(prog)
	checkVMFailed(t, v) // size = 2049 = (Max/2-1)*2+3 = Max+1
}

func TestStackLimit(t *testing.T) {
	expected := []struct {
		inst Instruction
		size int
	}{
		{PUSH2, 1},
		{NEWARRAY, 3}, // array + 2 items
		{TOALTSTACK, 3},
		{DUPFROMALTSTACK, 4},
		{NEWSTRUCT, 6}, // all items are copied
		{NEWMAP, 7},
		{DUP, 8},
		{PUSH2, 9},
		{DUPFROMALTSTACK, 10},
		{SETITEM, 8}, // -3 items and 1 new element in map
		{DUP, 9},
		{PUSH2, 10},
		{DUPFROMALTSTACK, 11},
		{SETITEM, 8}, // -3 items and no new elements in map
		{DUP, 9},
		{PUSH2, 10},
		{REMOVE, 7}, // as we have right after NEWMAP
		{DROP, 6},   // DROP map with no elements
	}

	prog := make([]Instruction, len(expected))
	for i := range expected {
		prog[i] = expected[i].inst
	}

	vm := load(makeProgram(prog...))
	for i := range expected {
		require.NoError(t, vm.Step())
		require.Equal(t, expected[i].size, vm.size)
	}
}

func TestPushBytesShort(t *testing.T) {
	prog := make([]byte, 10)
	prog[0] = byte(PUSHBYTES10) // but only 9 left in the `prog`
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestPushm1to16(t *testing.T) {
	var prog []byte
	for i := int(PUSHM1); i <= int(PUSH16); i++ {
		if i == 80 {
			continue // opcode layout we got here.
		}
		prog = append(prog, byte(i))
	}

	vm := load(prog)
	for i := int(PUSHM1); i <= int(PUSH16); i++ {
		if i == 80 {
			continue // nice opcode layout we got here.
		}
		err := vm.Step()
		require.NoError(t, err)

		elem := vm.estack.Pop()
		assert.IsType(t, &BigIntegerItem{}, elem.value)
		val := i - int(PUSH1) + 1
		assert.Equal(t, elem.BigInt().Int64(), int64(val))
	}
}

func TestPushData1BadNoN(t *testing.T) {
	prog := []byte{byte(PUSHDATA1)}
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestPushData1BadN(t *testing.T) {
	prog := []byte{byte(PUSHDATA1), 1}
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestPushData1Good(t *testing.T) {
	prog := makeProgram(PUSHDATA1, 3, 1, 2, 3)
	vm := load(prog)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte{1, 2, 3}, vm.estack.Pop().Bytes())
}

func TestPushData2BadNoN(t *testing.T) {
	prog := []byte{byte(PUSHDATA2)}
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestPushData2ShortN(t *testing.T) {
	prog := []byte{byte(PUSHDATA2), 0}
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestPushData2BadN(t *testing.T) {
	prog := []byte{byte(PUSHDATA2), 1, 0}
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestPushData2Good(t *testing.T) {
	prog := makeProgram(PUSHDATA2, 3, 0, 1, 2, 3)
	vm := load(prog)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte{1, 2, 3}, vm.estack.Pop().Bytes())
}

func TestPushData4BadNoN(t *testing.T) {
	prog := []byte{byte(PUSHDATA4)}
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestPushData4BadN(t *testing.T) {
	prog := []byte{byte(PUSHDATA4), 1, 0, 0, 0}
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestPushData4ShortN(t *testing.T) {
	prog := []byte{byte(PUSHDATA4), 0, 0, 0}
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestPushData4BigN(t *testing.T) {
	prog := make([]byte, 1+4+MaxItemSize+1)
	prog[0] = byte(PUSHDATA4)
	binary.LittleEndian.PutUint32(prog[1:], MaxItemSize+1)

	vm := load(prog)
	vm.Run()
	assert.Equal(t, true, vm.HasFailed())
}

func TestPushData4Good(t *testing.T) {
	prog := makeProgram(PUSHDATA4, 3, 0, 0, 0, 1, 2, 3)
	vm := load(prog)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte{1, 2, 3}, vm.estack.Pop().Bytes())
}

func getSyscallProg(name string) (prog []byte) {
	prog = []byte{byte(SYSCALL)}
	prog = append(prog, byte(len(name)))
	prog = append(prog, name...)

	return
}

func getSerializeProg() (prog []byte) {
	prog = append(prog, getSyscallProg("Neo.Runtime.Serialize")...)
	prog = append(prog, getSyscallProg("Neo.Runtime.Deserialize")...)
	prog = append(prog, byte(RET))

	return
}

func testSerialize(t *testing.T, vm *VM) {
	err := vm.Step()
	require.NoError(t, err)
	require.Equal(t, 1, vm.estack.Len())
	require.IsType(t, (*ByteArrayItem)(nil), vm.estack.Top().value)

	err = vm.Step()
	require.NoError(t, err)
	require.Equal(t, 1, vm.estack.Len())
}

func TestSerializeBool(t *testing.T) {
	vm := load(getSerializeProg())
	vm.estack.PushVal(true)

	testSerialize(t, vm)

	require.IsType(t, (*BoolItem)(nil), vm.estack.Top().value)
	require.Equal(t, true, vm.estack.Top().Bool())
}

func TestSerializeByteArray(t *testing.T) {
	vm := load(getSerializeProg())
	value := []byte{1, 2, 3}
	vm.estack.PushVal(value)

	testSerialize(t, vm)

	require.IsType(t, (*ByteArrayItem)(nil), vm.estack.Top().value)
	require.Equal(t, value, vm.estack.Top().Bytes())
}

func TestSerializeInteger(t *testing.T) {
	vm := load(getSerializeProg())
	value := int64(123)
	vm.estack.PushVal(value)

	testSerialize(t, vm)

	require.IsType(t, (*BigIntegerItem)(nil), vm.estack.Top().value)
	require.Equal(t, value, vm.estack.Top().BigInt().Int64())
}

func TestSerializeArray(t *testing.T) {
	vm := load(getSerializeProg())
	item := NewArrayItem([]StackItem{
		makeStackItem(true),
		makeStackItem(123),
		NewMapItem(),
	})

	vm.estack.Push(&Element{value: item})

	testSerialize(t, vm)

	require.IsType(t, (*ArrayItem)(nil), vm.estack.Top().value)
	require.Equal(t, item.value, vm.estack.Top().Array())
}

func TestSerializeArrayBad(t *testing.T) {
	vm := load(getSerializeProg())
	item := NewArrayItem(makeArrayOfFalses(2))
	item.value[1] = item

	vm.estack.Push(&Element{value: item})

	err := vm.Step()
	require.Error(t, err)
	require.True(t, vm.HasFailed())
}

func TestSerializeDupInteger(t *testing.T) {
	prog := []byte{
		byte(PUSH0), byte(NEWARRAY),
		byte(DUP), byte(PUSH2), byte(DUP), byte(TOALTSTACK), byte(APPEND),
		byte(DUP), byte(FROMALTSTACK), byte(APPEND),
	}
	vm := load(append(prog, getSerializeProg()...))

	runVM(t, vm)
}

func TestSerializeStruct(t *testing.T) {
	vm := load(getSerializeProg())
	item := NewStructItem([]StackItem{
		makeStackItem(true),
		makeStackItem(123),
		NewMapItem(),
	})

	vm.estack.Push(&Element{value: item})

	testSerialize(t, vm)

	require.IsType(t, (*StructItem)(nil), vm.estack.Top().value)
	require.Equal(t, item.value, vm.estack.Top().Array())
}

func TestDeserializeUnknown(t *testing.T) {
	prog := append(getSyscallProg("Neo.Runtime.Deserialize"), byte(RET))
	vm := load(prog)

	data, err := serializeItem(NewBigIntegerItem(123))
	require.NoError(t, err)

	data[0] = 0xFF
	vm.estack.PushVal(data)

	checkVMFailed(t, vm)
}

func TestSerializeMap(t *testing.T) {
	vm := load(getSerializeProg())
	item := NewMapItem()
	item.Add(makeStackItem(true), makeStackItem([]byte{1, 2, 3}))
	item.Add(makeStackItem([]byte{0}), makeStackItem(false))

	vm.estack.Push(&Element{value: item})

	testSerialize(t, vm)

	require.IsType(t, (*MapItem)(nil), vm.estack.Top().value)
	require.Equal(t, item.value, vm.estack.Top().value.(*MapItem).value)
}

func TestSerializeInterop(t *testing.T) {
	vm := load(getSerializeProg())
	item := NewInteropItem("kek")

	vm.estack.Push(&Element{value: item})

	err := vm.Step()
	require.Error(t, err)
	require.True(t, vm.HasFailed())
}

func callNTimes(n uint16) []byte {
	return makeProgram(
		PUSHBYTES2, Instruction(n), Instruction(n>>8), // little-endian
		TOALTSTACK, DUPFROMALTSTACK,
		JMPIF, 0x4, 0, RET,
		FROMALTSTACK, DEC,
		CALL, 0xF8, 0xFF) // -8 -> JMP to TOALTSTACK)
}

func TestInvocationLimitGood(t *testing.T) {
	prog := callNTimes(MaxInvocationStackSize - 1)
	v := load(prog)
	runVM(t, v)
}

func TestInvocationLimitBad(t *testing.T) {
	prog := callNTimes(MaxInvocationStackSize)
	v := load(prog)
	checkVMFailed(t, v)
}

func TestNOTNoArgument(t *testing.T) {
	prog := makeProgram(NOT)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestNOTBool(t *testing.T) {
	prog := makeProgram(NOT)
	vm := load(prog)
	vm.estack.PushVal(false)
	runVM(t, vm)
	assert.Equal(t, &BoolItem{true}, vm.estack.Pop().value)
}

func TestNOTNonZeroInt(t *testing.T) {
	prog := makeProgram(NOT)
	vm := load(prog)
	vm.estack.PushVal(3)
	runVM(t, vm)
	assert.Equal(t, &BoolItem{false}, vm.estack.Pop().value)
}

func TestNOTArray(t *testing.T) {
	prog := makeProgram(NOT)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{})
	runVM(t, vm)
	assert.Equal(t, &BoolItem{false}, vm.estack.Pop().value)
}

func TestNOTStruct(t *testing.T) {
	prog := makeProgram(NOT)
	vm := load(prog)
	vm.estack.Push(NewElement(&StructItem{[]StackItem{}}))
	runVM(t, vm)
	assert.Equal(t, &BoolItem{false}, vm.estack.Pop().value)
}

func TestNOTByteArray0(t *testing.T) {
	prog := makeProgram(NOT)
	vm := load(prog)
	vm.estack.PushVal([]byte{0, 0})
	runVM(t, vm)
	assert.Equal(t, &BoolItem{true}, vm.estack.Pop().value)
}

func TestNOTByteArray1(t *testing.T) {
	prog := makeProgram(NOT)
	vm := load(prog)
	vm.estack.PushVal([]byte{0, 1})
	runVM(t, vm)
	assert.Equal(t, &BoolItem{false}, vm.estack.Pop().value)
}

// getBigInt returns 2^a+b
func getBigInt(a, b int64) *big.Int {
	p := new(big.Int).Exp(big.NewInt(2), big.NewInt(a), nil)
	p.Add(p, big.NewInt(b))
	return p
}

func TestAdd(t *testing.T) {
	prog := makeProgram(ADD)
	vm := load(prog)
	vm.estack.PushVal(4)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, int64(6), vm.estack.Pop().BigInt().Int64())
}

func TestADDBigResult(t *testing.T) {
	prog := makeProgram(ADD)
	vm := load(prog)
	vm.estack.PushVal(getBigInt(MaxBigIntegerSizeBits, -1))
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func testBigArgument(t *testing.T, inst Instruction) {
	prog := makeProgram(inst)
	x := getBigInt(MaxBigIntegerSizeBits, 0)
	t.Run(inst.String()+" big 1-st argument", func(t *testing.T) {
		vm := load(prog)
		vm.estack.PushVal(x)
		vm.estack.PushVal(0)
		checkVMFailed(t, vm)
	})
	t.Run(inst.String()+" big 2-nd argument", func(t *testing.T) {
		vm := load(prog)
		vm.estack.PushVal(0)
		vm.estack.PushVal(x)
		checkVMFailed(t, vm)
	})
}

func TestArithBigArgument(t *testing.T) {
	testBigArgument(t, ADD)
	testBigArgument(t, SUB)
	testBigArgument(t, MUL)
	testBigArgument(t, DIV)
	testBigArgument(t, MOD)
}

func TestMul(t *testing.T) {
	prog := makeProgram(MUL)
	vm := load(prog)
	vm.estack.PushVal(4)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, int64(8), vm.estack.Pop().BigInt().Int64())
}

func TestMULBigResult(t *testing.T) {
	prog := makeProgram(MUL)
	vm := load(prog)
	vm.estack.PushVal(getBigInt(MaxBigIntegerSizeBits/2+1, 0))
	vm.estack.PushVal(getBigInt(MaxBigIntegerSizeBits/2+1, 0))
	checkVMFailed(t, vm)
}

func TestDiv(t *testing.T) {
	prog := makeProgram(DIV)
	vm := load(prog)
	vm.estack.PushVal(4)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, int64(2), vm.estack.Pop().BigInt().Int64())
}

func TestSub(t *testing.T) {
	prog := makeProgram(SUB)
	vm := load(prog)
	vm.estack.PushVal(4)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, int64(2), vm.estack.Pop().BigInt().Int64())
}

func TestSUBBigResult(t *testing.T) {
	prog := makeProgram(SUB)
	vm := load(prog)
	vm.estack.PushVal(getBigInt(MaxBigIntegerSizeBits, -1))
	vm.estack.PushVal(-1)
	checkVMFailed(t, vm)
}

func TestSHRGood(t *testing.T) {
	prog := makeProgram(SHR)
	vm := load(prog)
	vm.estack.PushVal(4)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(1), vm.estack.Pop().value)
}

func TestSHRZero(t *testing.T) {
	prog := makeProgram(SHR)
	vm := load(prog)
	vm.estack.PushVal([]byte{0, 1})
	vm.estack.PushVal(0)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem([]byte{0, 1}), vm.estack.Pop().value)
}

func TestSHRSmallValue(t *testing.T) {
	prog := makeProgram(SHR)
	vm := load(prog)
	vm.estack.PushVal(5)
	vm.estack.PushVal(minSHLArg - 1)
	checkVMFailed(t, vm)
}

func TestSHRBigArgument(t *testing.T) {
	prog := makeProgram(SHR)
	vm := load(prog)
	vm.estack.PushVal(getBigInt(MaxBigIntegerSizeBits, 0))
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestSHLGood(t *testing.T) {
	prog := makeProgram(SHL)
	vm := load(prog)
	vm.estack.PushVal(4)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(16), vm.estack.Pop().value)
}

func TestSHLZero(t *testing.T) {
	prog := makeProgram(SHL)
	vm := load(prog)
	vm.estack.PushVal([]byte{0, 1})
	vm.estack.PushVal(0)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem([]byte{0, 1}), vm.estack.Pop().value)
}

func TestSHLBigValue(t *testing.T) {
	prog := makeProgram(SHL)
	vm := load(prog)
	vm.estack.PushVal(5)
	vm.estack.PushVal(maxSHLArg + 1)
	checkVMFailed(t, vm)
}

func TestSHLBigResult(t *testing.T) {
	prog := makeProgram(SHL)
	vm := load(prog)
	vm.estack.PushVal(getBigInt(MaxBigIntegerSizeBits/2, 0))
	vm.estack.PushVal(MaxBigIntegerSizeBits / 2)
	checkVMFailed(t, vm)
}

func TestSHLBigArgument(t *testing.T) {
	prog := makeProgram(SHR)
	vm := load(prog)
	vm.estack.PushVal(getBigInt(MaxBigIntegerSizeBits, 0))
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestLT(t *testing.T) {
	prog := makeProgram(LT)
	vm := load(prog)
	vm.estack.PushVal(4)
	vm.estack.PushVal(3)
	runVM(t, vm)
	assert.Equal(t, false, vm.estack.Pop().Bool())
}

func TestLTE(t *testing.T) {
	prog := makeProgram(LTE)
	vm := load(prog)
	vm.estack.PushVal(2)
	vm.estack.PushVal(3)
	runVM(t, vm)
	assert.Equal(t, true, vm.estack.Pop().Bool())
}

func TestGT(t *testing.T) {
	prog := makeProgram(GT)
	vm := load(prog)
	vm.estack.PushVal(9)
	vm.estack.PushVal(3)
	runVM(t, vm)
	assert.Equal(t, true, vm.estack.Pop().Bool())

}

func TestGTE(t *testing.T) {
	prog := makeProgram(GTE)
	vm := load(prog)
	vm.estack.PushVal(3)
	vm.estack.PushVal(3)
	runVM(t, vm)
	assert.Equal(t, true, vm.estack.Pop().Bool())
}

func TestDepth(t *testing.T) {
	prog := makeProgram(DEPTH)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	vm.estack.PushVal(3)
	runVM(t, vm)
	assert.Equal(t, int64(3), vm.estack.Pop().BigInt().Int64())
}

func TestEQUALNoArguments(t *testing.T) {
	prog := makeProgram(EQUAL)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestEQUALBad1Argument(t *testing.T) {
	prog := makeProgram(EQUAL)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestEQUALGoodInteger(t *testing.T) {
	prog := makeProgram(EQUAL)
	vm := load(prog)
	vm.estack.PushVal(5)
	vm.estack.PushVal(5)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BoolItem{true}, vm.estack.Pop().value)
}

func TestEQUALArrayTrue(t *testing.T) {
	prog := makeProgram(DUP, EQUAL)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BoolItem{true}, vm.estack.Pop().value)
}

func TestEQUALArrayFalse(t *testing.T) {
	prog := makeProgram(EQUAL)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{})
	vm.estack.PushVal([]StackItem{})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BoolItem{false}, vm.estack.Pop().value)
}

func TestEQUALMapTrue(t *testing.T) {
	prog := makeProgram(DUP, EQUAL)
	vm := load(prog)
	vm.estack.Push(&Element{value: NewMapItem()})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BoolItem{true}, vm.estack.Pop().value)
}

func TestEQUALMapFalse(t *testing.T) {
	prog := makeProgram(EQUAL)
	vm := load(prog)
	vm.estack.Push(&Element{value: NewMapItem()})
	vm.estack.Push(&Element{value: NewMapItem()})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BoolItem{false}, vm.estack.Pop().value)
}

func TestNumEqual(t *testing.T) {
	prog := makeProgram(NUMEQUAL)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, false, vm.estack.Pop().Bool())
}

func TestNumNotEqual(t *testing.T) {
	prog := makeProgram(NUMNOTEQUAL)
	vm := load(prog)
	vm.estack.PushVal(2)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, false, vm.estack.Pop().Bool())
}

func TestINC(t *testing.T) {
	prog := makeProgram(INC)
	vm := load(prog)
	vm.estack.PushVal(1)
	runVM(t, vm)
	assert.Equal(t, big.NewInt(2), vm.estack.Pop().BigInt())
}

func TestINCBigResult(t *testing.T) {
	prog := makeProgram(INC, INC)
	vm := load(prog)
	x := getBigInt(MaxBigIntegerSizeBits, -2)
	vm.estack.PushVal(x)

	require.NoError(t, vm.Step())
	require.False(t, vm.HasFailed())
	require.Equal(t, 1, vm.estack.Len())
	require.Equal(t, new(big.Int).Add(x, big.NewInt(1)), vm.estack.Top().BigInt())

	checkVMFailed(t, vm)
}

func TestDECBigResult(t *testing.T) {
	prog := makeProgram(DEC, DEC)
	vm := load(prog)
	x := getBigInt(MaxBigIntegerSizeBits, -2)
	x.Neg(x)
	vm.estack.PushVal(x)

	require.NoError(t, vm.Step())
	require.False(t, vm.HasFailed())
	require.Equal(t, 1, vm.estack.Len())
	require.Equal(t, new(big.Int).Sub(x, big.NewInt(1)), vm.estack.Top().BigInt())

	checkVMFailed(t, vm)
}

func TestNEWARRAYInteger(t *testing.T) {
	prog := makeProgram(NEWARRAY)
	vm := load(prog)
	vm.estack.PushVal(1)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &ArrayItem{[]StackItem{makeStackItem(false)}}, vm.estack.Pop().value)
}

func TestNEWARRAYStruct(t *testing.T) {
	prog := makeProgram(NEWARRAY)
	vm := load(prog)
	arr := []StackItem{makeStackItem(42)}
	vm.estack.Push(&Element{value: &StructItem{arr}})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &ArrayItem{arr}, vm.estack.Pop().value)
}

func testNEWARRAYIssue437(t *testing.T, i1, i2 Instruction, appended bool) {
	prog := makeProgram(
		PUSH2, i1,
		DUP, PUSH3, APPEND,
		TOALTSTACK, DUPFROMALTSTACK, i2,
		DUP, PUSH4, APPEND,
		FROMALTSTACK, PUSH5, APPEND)
	vm := load(prog)
	vm.Run()

	arr := makeArrayOfFalses(4)
	arr[2] = makeStackItem(3)
	arr[3] = makeStackItem(4)
	if appended {
		arr = append(arr, makeStackItem(5))
	}

	assert.Equal(t, false, vm.HasFailed())
	assert.Equal(t, 1, vm.estack.Len())
	if i2 == NEWARRAY {
		assert.Equal(t, &ArrayItem{arr}, vm.estack.Pop().value)
	} else {
		assert.Equal(t, &StructItem{arr}, vm.estack.Pop().value)
	}
}

func TestNEWARRAYIssue437(t *testing.T) {
	t.Run("Array+Array", func(t *testing.T) { testNEWARRAYIssue437(t, NEWARRAY, NEWARRAY, true) })
	t.Run("Struct+Struct", func(t *testing.T) { testNEWARRAYIssue437(t, NEWSTRUCT, NEWSTRUCT, true) })
	t.Run("Array+Struct", func(t *testing.T) { testNEWARRAYIssue437(t, NEWARRAY, NEWSTRUCT, false) })
	t.Run("Struct+Array", func(t *testing.T) { testNEWARRAYIssue437(t, NEWSTRUCT, NEWARRAY, false) })
}

func TestNEWARRAYArray(t *testing.T) {
	prog := makeProgram(NEWARRAY)
	vm := load(prog)
	arr := []StackItem{makeStackItem(42)}
	vm.estack.Push(&Element{value: &ArrayItem{arr}})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &ArrayItem{arr}, vm.estack.Pop().value)
}

func TestNEWARRAYByteArray(t *testing.T) {
	prog := makeProgram(NEWARRAY)
	vm := load(prog)
	vm.estack.PushVal([]byte{})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &ArrayItem{[]StackItem{}}, vm.estack.Pop().value)
}

func TestNEWARRAYBadSize(t *testing.T) {
	prog := makeProgram(NEWARRAY)
	vm := load(prog)
	vm.estack.PushVal(MaxArraySize + 1)
	checkVMFailed(t, vm)
}

func TestNEWSTRUCTInteger(t *testing.T) {
	prog := makeProgram(NEWSTRUCT)
	vm := load(prog)
	vm.estack.PushVal(1)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &StructItem{[]StackItem{makeStackItem(false)}}, vm.estack.Pop().value)
}

func TestNEWSTRUCTArray(t *testing.T) {
	prog := makeProgram(NEWSTRUCT)
	vm := load(prog)
	arr := []StackItem{makeStackItem(42)}
	vm.estack.Push(&Element{value: &ArrayItem{arr}})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &StructItem{arr}, vm.estack.Pop().value)
}

func TestNEWSTRUCTStruct(t *testing.T) {
	prog := makeProgram(NEWSTRUCT)
	vm := load(prog)
	arr := []StackItem{makeStackItem(42)}
	vm.estack.Push(&Element{value: &StructItem{arr}})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &StructItem{arr}, vm.estack.Pop().value)
}

func TestNEWSTRUCTByteArray(t *testing.T) {
	prog := makeProgram(NEWSTRUCT)
	vm := load(prog)
	vm.estack.PushVal([]byte{})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &StructItem{[]StackItem{}}, vm.estack.Pop().value)
}

func TestNEWSTRUCTBadSize(t *testing.T) {
	prog := makeProgram(NEWSTRUCT)
	vm := load(prog)
	vm.estack.PushVal(MaxArraySize + 1)
	checkVMFailed(t, vm)
}

func TestAPPENDArray(t *testing.T) {
	prog := makeProgram(DUP, PUSH5, APPEND)
	vm := load(prog)
	vm.estack.Push(&Element{value: &ArrayItem{}})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &ArrayItem{[]StackItem{makeStackItem(5)}}, vm.estack.Pop().value)
}

func TestAPPENDStruct(t *testing.T) {
	prog := makeProgram(DUP, PUSH5, APPEND)
	vm := load(prog)
	vm.estack.Push(&Element{value: &StructItem{}})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &StructItem{[]StackItem{makeStackItem(5)}}, vm.estack.Pop().value)
}

func TestAPPENDCloneStruct(t *testing.T) {
	prog := makeProgram(DUP, PUSH0, NEWSTRUCT, TOALTSTACK, DUPFROMALTSTACK, APPEND, FROMALTSTACK, PUSH1, APPEND)
	vm := load(prog)
	vm.estack.Push(&Element{value: &ArrayItem{}})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &ArrayItem{[]StackItem{
		&StructItem{[]StackItem{}},
	}}, vm.estack.Pop().value)
}

func TestAPPENDBadNoArguments(t *testing.T) {
	prog := makeProgram(APPEND)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestAPPENDBad1Argument(t *testing.T) {
	prog := makeProgram(APPEND)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestAPPENDWrongType(t *testing.T) {
	prog := makeProgram(APPEND)
	vm := load(prog)
	vm.estack.PushVal([]byte{})
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestAPPENDGoodSizeLimit(t *testing.T) {
	prog := makeProgram(NEWARRAY, DUP, PUSH0, APPEND)
	vm := load(prog)
	vm.estack.PushVal(MaxArraySize - 1)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, MaxArraySize, len(vm.estack.Pop().Array()))
}

func TestAPPENDBadSizeLimit(t *testing.T) {
	prog := makeProgram(NEWARRAY, DUP, PUSH0, APPEND)
	vm := load(prog)
	vm.estack.PushVal(MaxArraySize)
	checkVMFailed(t, vm)
}

func TestPICKITEMBadIndex(t *testing.T) {
	prog := makeProgram(PICKITEM)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{})
	vm.estack.PushVal(0)
	checkVMFailed(t, vm)
}

func TestPICKITEMArray(t *testing.T) {
	prog := makeProgram(PICKITEM)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{makeStackItem(1), makeStackItem(2)})
	vm.estack.PushVal(1)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(2), vm.estack.Pop().value)
}

func TestPICKITEMByteArray(t *testing.T) {
	prog := makeProgram(PICKITEM)
	vm := load(prog)
	vm.estack.PushVal([]byte{1, 2})
	vm.estack.PushVal(1)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(2), vm.estack.Pop().value)
}

func TestPICKITEMMap(t *testing.T) {
	prog := makeProgram(PICKITEM)
	vm := load(prog)

	m := NewMapItem()
	m.Add(makeStackItem(5), makeStackItem(3))
	vm.estack.Push(&Element{value: m})
	vm.estack.PushVal(makeStackItem(5))

	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(3), vm.estack.Pop().value)
}

func TestSETITEMMap(t *testing.T) {
	prog := makeProgram(SETITEM, PICKITEM)
	vm := load(prog)

	m := NewMapItem()
	m.Add(makeStackItem(5), makeStackItem(3))
	vm.estack.Push(&Element{value: m})
	vm.estack.PushVal(5)
	vm.estack.Push(&Element{value: m})
	vm.estack.PushVal(5)
	vm.estack.PushVal([]byte{0, 1})

	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem([]byte{0, 1}), vm.estack.Pop().value)
}

func TestSETITEMBigMapBad(t *testing.T) {
	prog := makeProgram(SETITEM)
	vm := load(prog)

	m := NewMapItem()
	for i := 0; i < MaxArraySize; i++ {
		m.Add(makeStackItem(i), makeStackItem(i))
	}
	vm.estack.Push(&Element{value: m})
	vm.estack.PushVal(MaxArraySize)
	vm.estack.PushVal(0)

	checkVMFailed(t, vm)
}

func TestSETITEMBigMapGood(t *testing.T) {
	prog := makeProgram(SETITEM)
	vm := load(prog)

	m := NewMapItem()
	for i := 0; i < MaxArraySize; i++ {
		m.Add(makeStackItem(i), makeStackItem(i))
	}
	vm.estack.Push(&Element{value: m})
	vm.estack.PushVal(0)
	vm.estack.PushVal(0)

	runVM(t, vm)
}

func TestSIZENoArgument(t *testing.T) {
	prog := makeProgram(SIZE)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestSIZEByteArray(t *testing.T) {
	prog := makeProgram(SIZE)
	vm := load(prog)
	vm.estack.PushVal([]byte{0, 1})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(2), vm.estack.Pop().value)
}

func TestSIZEBool(t *testing.T) {
	prog := makeProgram(SIZE)
	vm := load(prog)
	vm.estack.PushVal(false)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	// assert.Equal(t, makeStackItem(1), vm.estack.Pop().value)
	// FIXME revert when NEO 3.0 https://github.com/nspcc-dev/neo-go/issues/477
	assert.Equal(t, makeStackItem(0), vm.estack.Pop().value)
}

func TestARRAYSIZEArray(t *testing.T) {
	prog := makeProgram(ARRAYSIZE)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{
		makeStackItem(1),
		makeStackItem([]byte{}),
	})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(2), vm.estack.Pop().value)
}

func TestARRAYSIZEMap(t *testing.T) {
	prog := makeProgram(ARRAYSIZE)
	vm := load(prog)

	m := NewMapItem()
	m.Add(makeStackItem(5), makeStackItem(6))
	m.Add(makeStackItem([]byte{0, 1}), makeStackItem(6))
	vm.estack.Push(&Element{value: m})

	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(2), vm.estack.Pop().value)
}

func TestKEYSMap(t *testing.T) {
	prog := makeProgram(KEYS)
	vm := load(prog)

	m := NewMapItem()
	m.Add(makeStackItem(5), makeStackItem(6))
	m.Add(makeStackItem([]byte{0, 1}), makeStackItem(6))
	vm.estack.Push(&Element{value: m})

	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())

	top := vm.estack.Pop().value.(*ArrayItem)
	assert.Equal(t, 2, len(top.value))
	assert.Contains(t, top.value, makeStackItem(5))
	assert.Contains(t, top.value, makeStackItem([]byte{0, 1}))
}

func TestKEYSNoArgument(t *testing.T) {
	prog := makeProgram(KEYS)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestKEYSWrongType(t *testing.T) {
	prog := makeProgram(KEYS)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{})
	checkVMFailed(t, vm)
}

func TestVALUESMap(t *testing.T) {
	prog := makeProgram(VALUES)
	vm := load(prog)

	m := NewMapItem()
	m.Add(makeStackItem(5), makeStackItem([]byte{2, 3}))
	m.Add(makeStackItem([]byte{0, 1}), makeStackItem([]StackItem{}))
	vm.estack.Push(&Element{value: m})

	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())

	top := vm.estack.Pop().value.(*ArrayItem)
	assert.Equal(t, 2, len(top.value))
	assert.Contains(t, top.value, makeStackItem([]byte{2, 3}))
	assert.Contains(t, top.value, makeStackItem([]StackItem{}))
}

func TestVALUESArray(t *testing.T) {
	prog := makeProgram(VALUES)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{makeStackItem(4)})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &ArrayItem{[]StackItem{makeStackItem(4)}}, vm.estack.Pop().value)
}

func TestVALUESNoArgument(t *testing.T) {
	prog := makeProgram(VALUES)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestVALUESWrongType(t *testing.T) {
	prog := makeProgram(VALUES)
	vm := load(prog)
	vm.estack.PushVal(5)
	checkVMFailed(t, vm)
}

func TestHASKEYArrayTrue(t *testing.T) {
	prog := makeProgram(PUSH5, NEWARRAY, PUSH4, HASKEY)
	vm := load(prog)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(true), vm.estack.Pop().value)
}

func TestHASKEYArrayFalse(t *testing.T) {
	prog := makeProgram(PUSH5, NEWARRAY, PUSH5, HASKEY)
	vm := load(prog)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(false), vm.estack.Pop().value)
}

func TestHASKEYStructTrue(t *testing.T) {
	prog := makeProgram(PUSH5, NEWSTRUCT, PUSH4, HASKEY)
	vm := load(prog)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(true), vm.estack.Pop().value)
}

func TestHASKEYStructFalse(t *testing.T) {
	prog := makeProgram(PUSH5, NEWSTRUCT, PUSH5, HASKEY)
	vm := load(prog)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(false), vm.estack.Pop().value)
}

func TestHASKEYMapTrue(t *testing.T) {
	prog := makeProgram(HASKEY)
	vm := load(prog)
	m := NewMapItem()
	m.Add(makeStackItem(5), makeStackItem(6))
	vm.estack.Push(&Element{value: m})
	vm.estack.PushVal(5)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(true), vm.estack.Pop().value)
}

func TestHASKEYMapFalse(t *testing.T) {
	prog := makeProgram(HASKEY)
	vm := load(prog)
	m := NewMapItem()
	m.Add(makeStackItem(5), makeStackItem(6))
	vm.estack.Push(&Element{value: m})
	vm.estack.PushVal(6)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(false), vm.estack.Pop().value)
}

func TestHASKEYNoArguments(t *testing.T) {
	prog := makeProgram(HASKEY)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestHASKEY1Argument(t *testing.T) {
	prog := makeProgram(HASKEY)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestHASKEYWrongKeyType(t *testing.T) {
	prog := makeProgram(HASKEY)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{})
	vm.estack.PushVal([]StackItem{})
	checkVMFailed(t, vm)
}

func TestHASKEYWrongCollectionType(t *testing.T) {
	prog := makeProgram(HASKEY)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	checkVMFailed(t, vm)
}

func TestSIGNNoArgument(t *testing.T) {
	prog := makeProgram(SIGN)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestSIGNWrongType(t *testing.T) {
	prog := makeProgram(SIGN)
	vm := load(prog)
	vm.estack.PushVal([]StackItem{})
	checkVMFailed(t, vm)
}

func TestSIGNBool(t *testing.T) {
	prog := makeProgram(SIGN)
	vm := load(prog)
	vm.estack.PushVal(false)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BigIntegerItem{big.NewInt(0)}, vm.estack.Pop().value)
}

func TestSIGNPositiveInt(t *testing.T) {
	prog := makeProgram(SIGN)
	vm := load(prog)
	vm.estack.PushVal(1)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BigIntegerItem{big.NewInt(1)}, vm.estack.Pop().value)
}

func TestSIGNNegativeInt(t *testing.T) {
	prog := makeProgram(SIGN)
	vm := load(prog)
	vm.estack.PushVal(-1)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BigIntegerItem{big.NewInt(-1)}, vm.estack.Pop().value)
}

func TestSIGNZero(t *testing.T) {
	prog := makeProgram(SIGN)
	vm := load(prog)
	vm.estack.PushVal(0)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BigIntegerItem{big.NewInt(0)}, vm.estack.Pop().value)
}

func TestSIGNByteArray(t *testing.T) {
	prog := makeProgram(SIGN)
	vm := load(prog)
	vm.estack.PushVal([]byte{0, 1})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &BigIntegerItem{big.NewInt(1)}, vm.estack.Pop().value)
}

func TestAppCall(t *testing.T) {
	prog := []byte{byte(APPCALL)}
	hash := util.Uint160{}
	prog = append(prog, hash.Bytes()...)
	prog = append(prog, byte(RET))

	vm := load(prog)
	vm.SetScriptGetter(func(in util.Uint160) []byte {
		if in.Equals(hash) {
			return makeProgram(DEPTH)
		}
		return nil
	})
	vm.estack.PushVal(2)

	runVM(t, vm)
	elem := vm.estack.Pop() // depth should be 1
	assert.Equal(t, int64(1), elem.BigInt().Int64())
}

func TestSimpleCall(t *testing.T) {
	progStr := "52c56b525a7c616516006c766b00527ac46203006c766b00c3616c756653c56b6c766b00527ac46c766b51527ac46203006c766b00c36c766b51c393616c7566"
	result := 12

	prog, err := hex.DecodeString(progStr)
	if err != nil {
		t.Fatal(err)
	}
	vm := load(prog)
	runVM(t, vm)
	assert.Equal(t, result, int(vm.estack.Pop().BigInt().Int64()))
}

func TestNZtrue(t *testing.T) {
	prog := makeProgram(NZ)
	vm := load(prog)
	vm.estack.PushVal(1)
	runVM(t, vm)
	assert.Equal(t, true, vm.estack.Pop().Bool())
}

func TestNZfalse(t *testing.T) {
	prog := makeProgram(NZ)
	vm := load(prog)
	vm.estack.PushVal(0)
	runVM(t, vm)
	assert.Equal(t, false, vm.estack.Pop().Bool())
}

func TestPICKbadNoitem(t *testing.T) {
	prog := makeProgram(PICK)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestPICKbadNegative(t *testing.T) {
	prog := makeProgram(PICK)
	vm := load(prog)
	vm.estack.PushVal(-1)
	checkVMFailed(t, vm)
}

func TestPICKgood(t *testing.T) {
	prog := makeProgram(PICK)
	result := 2
	vm := load(prog)
	vm.estack.PushVal(0)
	vm.estack.PushVal(1)
	vm.estack.PushVal(result)
	vm.estack.PushVal(3)
	vm.estack.PushVal(4)
	vm.estack.PushVal(5)
	vm.estack.PushVal(3)
	runVM(t, vm)
	assert.Equal(t, int64(result), vm.estack.Pop().BigInt().Int64())
}

func TestROTBad(t *testing.T) {
	prog := makeProgram(ROT)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	checkVMFailed(t, vm)
}

func TestROTGood(t *testing.T) {
	prog := makeProgram(ROT)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	vm.estack.PushVal(3)
	runVM(t, vm)
	assert.Equal(t, 3, vm.estack.Len())
	assert.Equal(t, makeStackItem(1), vm.estack.Pop().value)
	assert.Equal(t, makeStackItem(3), vm.estack.Pop().value)
	assert.Equal(t, makeStackItem(2), vm.estack.Pop().value)
}

func TestXTUCKbadNoitem(t *testing.T) {
	prog := makeProgram(XTUCK)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestXTUCKbadNoN(t *testing.T) {
	prog := makeProgram(XTUCK)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	checkVMFailed(t, vm)
}

func TestXTUCKbadNegative(t *testing.T) {
	prog := makeProgram(XTUCK)
	vm := load(prog)
	vm.estack.PushVal(-1)
	checkVMFailed(t, vm)
}

func TestXTUCKbadZero(t *testing.T) {
	prog := makeProgram(XTUCK)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(0)
	checkVMFailed(t, vm)
}

func TestXTUCKgood(t *testing.T) {
	prog := makeProgram(XTUCK)
	topelement := 5
	xtuckdepth := 3
	vm := load(prog)
	vm.estack.PushVal(0)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	vm.estack.PushVal(3)
	vm.estack.PushVal(4)
	vm.estack.PushVal(topelement)
	vm.estack.PushVal(xtuckdepth)
	runVM(t, vm)
	assert.Equal(t, int64(topelement), vm.estack.Peek(0).BigInt().Int64())
	assert.Equal(t, int64(topelement), vm.estack.Peek(xtuckdepth).BigInt().Int64())
}

func TestTUCKbadNoitems(t *testing.T) {
	prog := makeProgram(TUCK)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestTUCKbadNoitem(t *testing.T) {
	prog := makeProgram(TUCK)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestTUCKgood(t *testing.T) {
	prog := makeProgram(TUCK)
	vm := load(prog)
	vm.estack.PushVal(42)
	vm.estack.PushVal(34)
	runVM(t, vm)
	assert.Equal(t, int64(34), vm.estack.Peek(0).BigInt().Int64())
	assert.Equal(t, int64(42), vm.estack.Peek(1).BigInt().Int64())
	assert.Equal(t, int64(34), vm.estack.Peek(2).BigInt().Int64())
}

func TestTUCKgood2(t *testing.T) {
	prog := makeProgram(TUCK)
	vm := load(prog)
	vm.estack.PushVal(11)
	vm.estack.PushVal(42)
	vm.estack.PushVal(34)
	runVM(t, vm)
	assert.Equal(t, int64(34), vm.estack.Peek(0).BigInt().Int64())
	assert.Equal(t, int64(42), vm.estack.Peek(1).BigInt().Int64())
	assert.Equal(t, int64(34), vm.estack.Peek(2).BigInt().Int64())
	assert.Equal(t, int64(11), vm.estack.Peek(3).BigInt().Int64())
}

func TestOVERbadNoitem(t *testing.T) {
	prog := makeProgram(OVER)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(1), vm.estack.Pop().value)
}

func TestOVERbadNoitems(t *testing.T) {
	prog := makeProgram(OVER)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestOVERgood(t *testing.T) {
	prog := makeProgram(OVER)
	vm := load(prog)
	vm.estack.PushVal(42)
	vm.estack.PushVal(34)
	runVM(t, vm)
	assert.Equal(t, int64(42), vm.estack.Peek(0).BigInt().Int64())
	assert.Equal(t, int64(34), vm.estack.Peek(1).BigInt().Int64())
	assert.Equal(t, int64(42), vm.estack.Peek(2).BigInt().Int64())
	assert.Equal(t, 3, vm.estack.Len())
}

func TestNIPBadNoItem(t *testing.T) {
	prog := makeProgram(NIP)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestNIPGood(t *testing.T) {
	prog := makeProgram(NIP)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(2), vm.estack.Pop().value)
}

func TestDROPBadNoItem(t *testing.T) {
	prog := makeProgram(DROP)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestDROPGood(t *testing.T) {
	prog := makeProgram(DROP)
	vm := load(prog)
	vm.estack.PushVal(1)
	runVM(t, vm)
	assert.Equal(t, 0, vm.estack.Len())
}

func TestXDROPbadNoitem(t *testing.T) {
	prog := makeProgram(XDROP)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestXDROPbadNoN(t *testing.T) {
	prog := makeProgram(XDROP)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	checkVMFailed(t, vm)
}

func TestXDROPbadNegative(t *testing.T) {
	prog := makeProgram(XDROP)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(-1)
	checkVMFailed(t, vm)
}

func TestXDROPgood(t *testing.T) {
	prog := makeProgram(XDROP)
	vm := load(prog)
	vm.estack.PushVal(0)
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, 2, vm.estack.Len())
	assert.Equal(t, int64(2), vm.estack.Peek(0).BigInt().Int64())
	assert.Equal(t, int64(1), vm.estack.Peek(1).BigInt().Int64())
}

func TestINVERTbadNoitem(t *testing.T) {
	prog := makeProgram(INVERT)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestINVERTgood1(t *testing.T) {
	prog := makeProgram(INVERT)
	vm := load(prog)
	vm.estack.PushVal(0)
	runVM(t, vm)
	assert.Equal(t, int64(-1), vm.estack.Peek(0).BigInt().Int64())
}

func TestINVERTgood2(t *testing.T) {
	prog := makeProgram(INVERT)
	vm := load(prog)
	vm.estack.PushVal(-1)
	runVM(t, vm)
	assert.Equal(t, int64(0), vm.estack.Peek(0).BigInt().Int64())
}

func TestINVERTgood3(t *testing.T) {
	prog := makeProgram(INVERT)
	vm := load(prog)
	vm.estack.PushVal(0x69)
	runVM(t, vm)
	assert.Equal(t, int64(-0x6A), vm.estack.Peek(0).BigInt().Int64())
}

func TestCATBadNoArgs(t *testing.T) {
	prog := makeProgram(CAT)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestCATBadOneArg(t *testing.T) {
	prog := makeProgram(CAT)
	vm := load(prog)
	vm.estack.PushVal([]byte("abc"))
	checkVMFailed(t, vm)
}

func TestCATBadBigItem(t *testing.T) {
	prog := makeProgram(CAT)
	vm := load(prog)
	vm.estack.PushVal(make([]byte, MaxItemSize/2+1))
	vm.estack.PushVal(make([]byte, MaxItemSize/2+1))
	vm.Run()
	assert.Equal(t, true, vm.HasFailed())
}

func TestCATGood(t *testing.T) {
	prog := makeProgram(CAT)
	vm := load(prog)
	vm.estack.PushVal([]byte("abc"))
	vm.estack.PushVal([]byte("def"))
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte("abcdef"), vm.estack.Peek(0).Bytes())
}

func TestCATInt0ByteArray(t *testing.T) {
	prog := makeProgram(CAT)
	vm := load(prog)
	vm.estack.PushVal(0)
	vm.estack.PushVal([]byte{})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &ByteArrayItem{[]byte{}}, vm.estack.Pop().value)
}

func TestCATByteArrayInt1(t *testing.T) {
	prog := makeProgram(CAT)
	vm := load(prog)
	vm.estack.PushVal([]byte{})
	vm.estack.PushVal(1)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, &ByteArrayItem{[]byte{1}}, vm.estack.Pop().value)
}

func TestSUBSTRBadNoArgs(t *testing.T) {
	prog := makeProgram(SUBSTR)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestSUBSTRBadOneArg(t *testing.T) {
	prog := makeProgram(SUBSTR)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestSUBSTRBadTwoArgs(t *testing.T) {
	prog := makeProgram(SUBSTR)
	vm := load(prog)
	vm.estack.PushVal(0)
	vm.estack.PushVal(2)
	checkVMFailed(t, vm)
}

func TestSUBSTRGood(t *testing.T) {
	prog := makeProgram(SUBSTR)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(1)
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte("bc"), vm.estack.Peek(0).Bytes())
}

func TestSUBSTRBadOffset(t *testing.T) {
	prog := makeProgram(SUBSTR)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(7)
	vm.estack.PushVal(1)

	// checkVMFailed(t, vm)
	// FIXME revert when NEO 3.0 https://github.com/nspcc-dev/neo-go/issues/477
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte{}, vm.estack.Peek(0).Bytes())
}

func TestSUBSTRBigLen(t *testing.T) {
	prog := makeProgram(SUBSTR)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(1)
	vm.estack.PushVal(6)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte("bcdef"), vm.estack.Pop().Bytes())
}

func TestSUBSTRBad387(t *testing.T) {
	prog := makeProgram(SUBSTR)
	vm := load(prog)
	b := make([]byte, 6, 20)
	copy(b, "abcdef")
	vm.estack.PushVal(b)
	vm.estack.PushVal(1)
	vm.estack.PushVal(6)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte("bcdef"), vm.estack.Pop().Bytes())
}

func TestSUBSTRBadNegativeOffset(t *testing.T) {
	prog := makeProgram(SUBSTR)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(-1)
	vm.estack.PushVal(3)
	checkVMFailed(t, vm)
}

func TestSUBSTRBadNegativeLen(t *testing.T) {
	prog := makeProgram(SUBSTR)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(3)
	vm.estack.PushVal(-1)
	checkVMFailed(t, vm)
}

func TestLEFTBadNoArgs(t *testing.T) {
	prog := makeProgram(LEFT)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestLEFTBadNoString(t *testing.T) {
	prog := makeProgram(LEFT)
	vm := load(prog)
	vm.estack.PushVal(2)
	checkVMFailed(t, vm)
}

func TestLEFTBadNegativeLen(t *testing.T) {
	prog := makeProgram(LEFT)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(-1)
	checkVMFailed(t, vm)
}

func TestLEFTGood(t *testing.T) {
	prog := makeProgram(LEFT)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte("ab"), vm.estack.Peek(0).Bytes())
}

func TestLEFTGoodLen(t *testing.T) {
	prog := makeProgram(LEFT)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(8)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte("abcdef"), vm.estack.Peek(0).Bytes())
}

func TestRIGHTBadNoArgs(t *testing.T) {
	prog := makeProgram(RIGHT)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestRIGHTBadNoString(t *testing.T) {
	prog := makeProgram(RIGHT)
	vm := load(prog)
	vm.estack.PushVal(2)
	checkVMFailed(t, vm)
}

func TestRIGHTBadNegativeLen(t *testing.T) {
	prog := makeProgram(RIGHT)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(-1)
	checkVMFailed(t, vm)
}

func TestRIGHTGood(t *testing.T) {
	prog := makeProgram(RIGHT)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(2)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []byte("ef"), vm.estack.Peek(0).Bytes())
}

func TestRIGHTBadLen(t *testing.T) {
	prog := makeProgram(RIGHT)
	vm := load(prog)
	vm.estack.PushVal([]byte("abcdef"))
	vm.estack.PushVal(8)
	checkVMFailed(t, vm)
}

func TestPACKBadLen(t *testing.T) {
	prog := makeProgram(PACK)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestPACKBigLen(t *testing.T) {
	prog := makeProgram(PACK)
	vm := load(prog)
	for i := 0; i <= MaxArraySize; i++ {
		vm.estack.PushVal(0)
	}
	vm.estack.PushVal(MaxArraySize + 1)
	checkVMFailed(t, vm)
}

func TestPACKGoodZeroLen(t *testing.T) {
	prog := makeProgram(PACK)
	vm := load(prog)
	vm.estack.PushVal(0)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, []StackItem{}, vm.estack.Peek(0).Array())
}

func TestPACKGood(t *testing.T) {
	prog := makeProgram(PACK)
	elements := []int{55, 34, 42}
	vm := load(prog)
	// canary
	vm.estack.PushVal(1)
	for i := len(elements) - 1; i >= 0; i-- {
		vm.estack.PushVal(elements[i])
	}
	vm.estack.PushVal(len(elements))
	runVM(t, vm)
	assert.Equal(t, 2, vm.estack.Len())
	a := vm.estack.Peek(0).Array()
	assert.Equal(t, len(elements), len(a))
	for i := 0; i < len(elements); i++ {
		e := a[i].Value().(*big.Int)
		assert.Equal(t, int64(elements[i]), e.Int64())
	}
	assert.Equal(t, int64(1), vm.estack.Peek(1).BigInt().Int64())
}

func TestUNPACKBadNotArray(t *testing.T) {
	prog := makeProgram(UNPACK)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestUNPACKGood(t *testing.T) {
	prog := makeProgram(UNPACK)
	elements := []int{55, 34, 42}
	vm := load(prog)
	// canary
	vm.estack.PushVal(1)
	vm.estack.PushVal(elements)
	runVM(t, vm)
	assert.Equal(t, 5, vm.estack.Len())
	assert.Equal(t, int64(len(elements)), vm.estack.Peek(0).BigInt().Int64())
	for k, v := range elements {
		assert.Equal(t, int64(v), vm.estack.Peek(k+1).BigInt().Int64())
	}
	assert.Equal(t, int64(1), vm.estack.Peek(len(elements)+1).BigInt().Int64())
}

func TestREVERSEBadNotArray(t *testing.T) {
	prog := makeProgram(REVERSE)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func testREVERSEIssue437(t *testing.T, i1, i2 Instruction, reversed bool) {
	prog := makeProgram(
		PUSH0, i1,
		DUP, PUSH1, APPEND,
		DUP, PUSH2, APPEND,
		DUP, i2, REVERSE)
	vm := load(prog)
	vm.Run()

	arr := make([]StackItem, 2)
	if reversed {
		arr[0] = makeStackItem(2)
		arr[1] = makeStackItem(1)
	} else {
		arr[0] = makeStackItem(1)
		arr[1] = makeStackItem(2)
	}
	assert.Equal(t, false, vm.HasFailed())
	assert.Equal(t, 1, vm.estack.Len())
	if i1 == NEWARRAY {
		assert.Equal(t, &ArrayItem{arr}, vm.estack.Pop().value)
	} else {
		assert.Equal(t, &StructItem{arr}, vm.estack.Pop().value)
	}
}

func TestREVERSEIssue437(t *testing.T) {
	t.Run("Array+Array", func(t *testing.T) { testREVERSEIssue437(t, NEWARRAY, NEWARRAY, true) })
	t.Run("Struct+Struct", func(t *testing.T) { testREVERSEIssue437(t, NEWSTRUCT, NEWSTRUCT, true) })
	t.Run("Array+Struct", func(t *testing.T) { testREVERSEIssue437(t, NEWARRAY, NEWSTRUCT, false) })
	t.Run("Struct+Array", func(t *testing.T) { testREVERSEIssue437(t, NEWSTRUCT, NEWARRAY, false) })
}

func TestREVERSEGoodOneElem(t *testing.T) {
	prog := makeProgram(DUP, REVERSE)
	elements := []int{22}
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(elements)
	runVM(t, vm)
	assert.Equal(t, 2, vm.estack.Len())
	a := vm.estack.Peek(0).Array()
	assert.Equal(t, len(elements), len(a))
	e := a[0].Value().(*big.Int)
	assert.Equal(t, int64(elements[0]), e.Int64())
}

func TestREVERSEGoodStruct(t *testing.T) {
	eodd := []int{22, 34, 42, 55, 81}
	even := []int{22, 34, 42, 55, 81, 99}
	eall := [][]int{eodd, even}

	for _, elements := range eall {
		prog := makeProgram(DUP, REVERSE)
		vm := load(prog)
		vm.estack.PushVal(1)

		arr := make([]StackItem, len(elements))
		for i := range elements {
			arr[i] = makeStackItem(elements[i])
		}
		vm.estack.Push(&Element{value: &StructItem{arr}})

		runVM(t, vm)
		assert.Equal(t, 2, vm.estack.Len())
		a := vm.estack.Peek(0).Array()
		assert.Equal(t, len(elements), len(a))
		for k, v := range elements {
			e := a[len(a)-1-k].Value().(*big.Int)
			assert.Equal(t, int64(v), e.Int64())
		}
		assert.Equal(t, int64(1), vm.estack.Peek(1).BigInt().Int64())
	}
}

func TestREVERSEGood(t *testing.T) {
	eodd := []int{22, 34, 42, 55, 81}
	even := []int{22, 34, 42, 55, 81, 99}
	eall := [][]int{eodd, even}

	for _, elements := range eall {
		prog := makeProgram(DUP, REVERSE)
		vm := load(prog)
		vm.estack.PushVal(1)
		vm.estack.PushVal(elements)
		runVM(t, vm)
		assert.Equal(t, 2, vm.estack.Len())
		a := vm.estack.Peek(0).Array()
		assert.Equal(t, len(elements), len(a))
		for k, v := range elements {
			e := a[len(a)-1-k].Value().(*big.Int)
			assert.Equal(t, int64(v), e.Int64())
		}
		assert.Equal(t, int64(1), vm.estack.Peek(1).BigInt().Int64())
	}
}

func TestREMOVEBadNoArgs(t *testing.T) {
	prog := makeProgram(REMOVE)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestREMOVEBadOneArg(t *testing.T) {
	prog := makeProgram(REMOVE)
	vm := load(prog)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestREMOVEBadNotArray(t *testing.T) {
	prog := makeProgram(REMOVE)
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(1)
	checkVMFailed(t, vm)
}

func TestREMOVEBadIndex(t *testing.T) {
	prog := makeProgram(REMOVE)
	elements := []int{22, 34, 42, 55, 81}
	vm := load(prog)
	vm.estack.PushVal(elements)
	vm.estack.PushVal(10)
	checkVMFailed(t, vm)
}

func TestREMOVEGood(t *testing.T) {
	prog := makeProgram(DUP, PUSH2, REMOVE)
	elements := []int{22, 34, 42, 55, 81}
	reselements := []int{22, 34, 55, 81}
	vm := load(prog)
	vm.estack.PushVal(1)
	vm.estack.PushVal(elements)
	runVM(t, vm)
	assert.Equal(t, 2, vm.estack.Len())
	assert.Equal(t, makeStackItem(reselements), vm.estack.Pop().value)
	assert.Equal(t, makeStackItem(1), vm.estack.Pop().value)
}

func TestREMOVEMap(t *testing.T) {
	prog := makeProgram(REMOVE, PUSH5, HASKEY)
	vm := load(prog)

	m := NewMapItem()
	m.Add(makeStackItem(5), makeStackItem(3))
	m.Add(makeStackItem([]byte{0, 1}), makeStackItem([]byte{2, 3}))
	vm.estack.Push(&Element{value: m})
	vm.estack.Push(&Element{value: m})
	vm.estack.PushVal(makeStackItem(5))

	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, makeStackItem(false), vm.estack.Pop().value)
}

func TestCHECKSIGNoArgs(t *testing.T) {
	prog := makeProgram(CHECKSIG)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestCHECKSIGOneArg(t *testing.T) {
	prog := makeProgram(CHECKSIG)
	pk, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	pbytes := pk.PublicKey().Bytes()
	vm := load(prog)
	vm.estack.PushVal(pbytes)
	checkVMFailed(t, vm)
}

func TestCHECKSIGNoSigLoaded(t *testing.T) {
	prog := makeProgram(CHECKSIG)
	pk, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := "NEO - An Open Network For Smart Economy"
	sig, err := pk.Sign([]byte(msg))
	assert.Nil(t, err)
	pbytes := pk.PublicKey().Bytes()
	vm := load(prog)
	vm.estack.PushVal(sig)
	vm.estack.PushVal(pbytes)
	checkVMFailed(t, vm)
}

func TestCHECKSIGBadKey(t *testing.T) {
	prog := makeProgram(CHECKSIG)
	pk, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig, err := pk.Sign(msg)
	assert.Nil(t, err)
	pbytes := pk.PublicKey().Bytes()[:4]
	vm := load(prog)
	vm.SetCheckedHash(hash.Sha256(msg).Bytes())
	vm.estack.PushVal(sig)
	vm.estack.PushVal(pbytes)
	checkVMFailed(t, vm)
}

func TestCHECKSIGWrongSig(t *testing.T) {
	prog := makeProgram(CHECKSIG)
	pk, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig, err := pk.Sign(msg)
	assert.Nil(t, err)
	pbytes := pk.PublicKey().Bytes()
	vm := load(prog)
	vm.SetCheckedHash(hash.Sha256(msg).Bytes())
	vm.estack.PushVal(util.ArrayReverse(sig))
	vm.estack.PushVal(pbytes)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, false, vm.estack.Pop().Bool())
}

func TestCHECKSIGGood(t *testing.T) {
	prog := makeProgram(CHECKSIG)
	pk, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig, err := pk.Sign(msg)
	assert.Nil(t, err)
	pbytes := pk.PublicKey().Bytes()
	vm := load(prog)
	vm.SetCheckedHash(hash.Sha256(msg).Bytes())
	vm.estack.PushVal(sig)
	vm.estack.PushVal(pbytes)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, true, vm.estack.Pop().Bool())
}

func TestVERIFYGood(t *testing.T) {
	prog := makeProgram(VERIFY)
	pk, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig, err := pk.Sign(msg)
	assert.Nil(t, err)
	pbytes := pk.PublicKey().Bytes()
	vm := load(prog)
	vm.estack.PushVal(msg)
	vm.estack.PushVal(sig)
	vm.estack.PushVal(pbytes)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, true, vm.estack.Pop().Bool())
}

func TestVERIFYBad(t *testing.T) {
	prog := makeProgram(VERIFY)
	pk, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig, err := pk.Sign(msg)
	assert.Nil(t, err)
	pbytes := pk.PublicKey().Bytes()
	vm := load(prog)
	vm.estack.PushVal(util.ArrayReverse(msg))
	vm.estack.PushVal(sig)
	vm.estack.PushVal(pbytes)
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, false, vm.estack.Pop().Bool())
}

func TestCHECKMULTISIGNoArgs(t *testing.T) {
	prog := makeProgram(CHECKMULTISIG)
	vm := load(prog)
	checkVMFailed(t, vm)
}

func TestCHECKMULTISIGOneArg(t *testing.T) {
	prog := makeProgram(CHECKMULTISIG)
	pk, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	vm := load(prog)
	pbytes := pk.PublicKey().Bytes()
	vm.estack.PushVal([]StackItem{NewByteArrayItem(pbytes)})
	checkVMFailed(t, vm)
}

func TestCHECKMULTISIGNotEnoughKeys(t *testing.T) {
	prog := makeProgram(CHECKMULTISIG)
	pk1, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	pk2, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig1, err := pk1.Sign(msg)
	assert.Nil(t, err)
	sig2, err := pk2.Sign(msg)
	assert.Nil(t, err)
	pbytes1 := pk1.PublicKey().Bytes()
	vm := load(prog)
	vm.SetCheckedHash(hash.Sha256(msg).Bytes())
	vm.estack.PushVal([]StackItem{NewByteArrayItem(sig1), NewByteArrayItem(sig2)})
	vm.estack.PushVal([]StackItem{NewByteArrayItem(pbytes1)})
	checkVMFailed(t, vm)
}

func TestCHECKMULTISIGNoHash(t *testing.T) {
	prog := makeProgram(CHECKMULTISIG)
	pk1, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	pk2, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig1, err := pk1.Sign(msg)
	assert.Nil(t, err)
	sig2, err := pk2.Sign(msg)
	assert.Nil(t, err)
	pbytes1 := pk1.PublicKey().Bytes()
	pbytes2 := pk2.PublicKey().Bytes()
	vm := load(prog)
	vm.estack.PushVal([]StackItem{NewByteArrayItem(sig1), NewByteArrayItem(sig2)})
	vm.estack.PushVal([]StackItem{NewByteArrayItem(pbytes1), NewByteArrayItem(pbytes2)})
	checkVMFailed(t, vm)
}

func TestCHECKMULTISIGBadKey(t *testing.T) {
	prog := makeProgram(CHECKMULTISIG)
	pk1, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	pk2, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig1, err := pk1.Sign(msg)
	assert.Nil(t, err)
	sig2, err := pk2.Sign(msg)
	assert.Nil(t, err)
	pbytes1 := pk1.PublicKey().Bytes()
	pbytes2 := pk2.PublicKey().Bytes()[:4]
	vm := load(prog)
	vm.SetCheckedHash(hash.Sha256(msg).Bytes())
	vm.estack.PushVal([]StackItem{NewByteArrayItem(sig1), NewByteArrayItem(sig2)})
	vm.estack.PushVal([]StackItem{NewByteArrayItem(pbytes1), NewByteArrayItem(pbytes2)})
	checkVMFailed(t, vm)
}

func TestCHECKMULTISIGBadSig(t *testing.T) {
	prog := makeProgram(CHECKMULTISIG)
	pk1, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	pk2, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig1, err := pk1.Sign(msg)
	assert.Nil(t, err)
	sig2, err := pk2.Sign(msg)
	assert.Nil(t, err)
	pbytes1 := pk1.PublicKey().Bytes()
	pbytes2 := pk2.PublicKey().Bytes()
	vm := load(prog)
	vm.SetCheckedHash(hash.Sha256(msg).Bytes())
	vm.estack.PushVal([]StackItem{NewByteArrayItem(util.ArrayReverse(sig1)), NewByteArrayItem(sig2)})
	vm.estack.PushVal([]StackItem{NewByteArrayItem(pbytes1), NewByteArrayItem(pbytes2)})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, false, vm.estack.Pop().Bool())
}

func TestCHECKMULTISIGGood(t *testing.T) {
	prog := makeProgram(CHECKMULTISIG)
	pk1, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	pk2, err := keys.NewPrivateKey()
	assert.Nil(t, err)
	msg := []byte("NEO - An Open Network For Smart Economy")
	sig1, err := pk1.Sign(msg)
	assert.Nil(t, err)
	sig2, err := pk2.Sign(msg)
	assert.Nil(t, err)
	pbytes1 := pk1.PublicKey().Bytes()
	pbytes2 := pk2.PublicKey().Bytes()
	vm := load(prog)
	vm.SetCheckedHash(hash.Sha256(msg).Bytes())
	vm.estack.PushVal([]StackItem{NewByteArrayItem(sig1), NewByteArrayItem(sig2)})
	vm.estack.PushVal([]StackItem{NewByteArrayItem(pbytes1), NewByteArrayItem(pbytes2)})
	runVM(t, vm)
	assert.Equal(t, 1, vm.estack.Len())
	assert.Equal(t, true, vm.estack.Pop().Bool())
}

func makeProgram(opcodes ...Instruction) []byte {
	prog := make([]byte, len(opcodes)+1) // RET
	for i := 0; i < len(opcodes); i++ {
		prog[i] = byte(opcodes[i])
	}
	prog[len(prog)-1] = byte(RET)
	return prog
}

func load(prog []byte) *VM {
	vm := New()
	vm.LoadScript(prog)
	return vm
}

func randomBytes(n int) []byte {
	const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
	b := make([]byte, n)
	for i := range b {
		b[i] = charset[rand.Intn(len(charset))]
	}
	return b
}