Merge branch 'vm' into dauTT/vm-bitwise-opcodes-191

pkg/vm/csharp-interop-test/push/pushbytes1.json

@@ -0,0 +1,81 @@
+{
+    "category": "Push",
+    "name": "PUSHBYTES1",
+    "tests":
+    [
+        {
+            "name": "Good definition",
+            "script": "0x0100",
+            "steps":
+            [
+                {
+                    "actions":
+                    [
+                        "StepInto"
+                    ],
+                    "result":
+                    {
+                        "state": "Break",
+                        "invocationStack":
+                        [
+                            {
+                                "scriptHash": "0xFBC22D517F38E7612798ECE8E5957CF6C41D8CAF",
+                                "instructionPointer": 2,
+                                "nextInstruction": "RET",
+                                "evaluationStack":
+                                [
+                                    {
+                                        "type": "ByteArray",
+                                        "value": "0x00"
+                                    }
+                                ]
+                            }
+                        ]
+                    }
+                },
+                {
+                    "actions":
+                    [
+                        "StepInto"
+                    ],
+                    "result":
+                    {
+                        "state": "Halt",
+                        "resultStack":
+                        [
+                            {
+                                "type": "ByteArray",
+                                "value": "0x00"
+                            }
+                        ]
+                    }
+                }
+            ]
+        },
+        {
+            "name": "Wrong definition (without enough length)",
+            "script": "0x01",
+            "steps":
+            [
+                {
+                    "actions":
+                    [
+                        "StepInto"
+                    ],
+                    "result":
+                    {
+                        "state": "Fault",
+                        "invocationStack":
+                        [
+                            {
+                                "scriptHash": "0xC51B66BCED5E4491001BD702669770DCCF440982",
+                                "instructionPointer": 1,
+                                "nextInstruction": "RET"
+                            }
+                        ]
+                    }
+                }
+            ]
+        }
+    ]
+}

pkg/vm/csharp-interop-test/readme.md

@@ -0,0 +1,6 @@
+## Package VM Interop
+
+
+This package will use the tests in the neo-vm repo to test interopabilty
+
+

pkg/vm/csharp-interop-test/testStruct.go

@@ -0,0 +1,26 @@
+package csharpinterop
+
+// VMUnitTest is a struct for capturing the fields in the json files
+type VMUnitTest struct {
+	Category string `json:"category"`
+	Name     string `json:"name"`
+	Tests    []struct {
+		Name   string `json:"name"`
+		Script string `json:"script"`
+		Steps  []struct {
+			Actions []string `json:"actions"`
+			Result  struct {
+				State           string `json:"state"`
+				InvocationStack []struct {
+					ScriptHash         string `json:"scriptHash"`
+					InstructionPointer int    `json:"instructionPointer"`
+					NextInstruction    string `json:"nextInstruction"`
+					EvaluationStack    []struct {
+						Type  string `json:"type"`
+						Value string `json:"value"`
+					} `json:"evaluationStack"`
+				} `json:"invocationStack"`
+			} `json:"result"`
+		} `json:"steps"`
+	} `json:"tests"`
+}

pkg/vm/stack/Int.go

@@ -1,6 +1,9 @@
 package stack
 
-import "math/big"
+import (
+	"fmt"
+	"math/big"
+)
 
 // Int represents an integer on the stack
 type Int struct {
@@ -100,6 +103,18 @@ func (i *Int) Value() *big.Int {
 	return i.val
 }
 
+// Abs returns a stack integer whose underlying value is
+// the absolute value of the original stack integer.
+func (i *Int) Abs() (*Int, error) {
+	a := big.NewInt(0).Abs(i.Value())
+	b, err := NewInt(a)
+	if err != nil {
+		return nil, err
+	}
+
+	return b, nil
+}
+
 // Lte returns a bool value from the comparison of two integers, a and b.
 // value is true if a <= b.
 // value is false if a > b.
@@ -114,18 +129,6 @@ func (i *Int) Gte(s *Int) bool {
 	return i.Value().Cmp(s.Value()) != -1
 }
 
-// Abs returns a stack integer whose underlying value is
-// the absolute value of the original stack integer.
-func (i *Int) Abs() (*Int, error) {
-	a := big.NewInt(0).Abs(i.Value())
-	b, err := NewInt(a)
-	if err != nil {
-		return nil, err
-	}
-
-	return b, nil
-}
-
 // Lt returns a bool value from the comparison of two integers, a and b.
 // value is true if a < b.
 // value is false if a >= b.
@@ -170,3 +173,33 @@ func (i *Int) Xor(s *Int) (*Int, error) {
 	res := new(big.Int).Xor(i.Value(), s.Value())
 	return NewInt(res)
 }
+
+// Hash overrides the default abstract hash method.
+func (i *Int) Hash() (string, error) {
+	data := fmt.Sprintf("%T %v", i, i.Value())
+	return KeyGenerator([]byte(data))
+}
+
+// Min returns the mininum between two integers.
+func Min(a *Int, b *Int) *Int {
+	if a.Lte(b) {
+		return a
+	}
+	return b
+}
+
+// Max returns the maximun between two integers.
+func Max(a *Int, b *Int) *Int {
+	if a.Gte(b) {
+		return a
+	}
+	return b
+}
+
+// Within returns a bool whose value is true
+// iff the value of the integer i is within the specified
+// range [a,b) (left-inclusive).
+func (i *Int) Within(a *Int, b *Int) bool {
+	// i >= a && i < b
+	return i.Gte(a) && i.Lt(b)
+}

pkg/vm/stack/array.go

@@ -1,5 +1,9 @@
 package stack
 
+import (
+	"fmt"
+)
+
 // Array represents an Array of stackItems on the stack
 type Array struct {
 	*abstractItem
@@ -11,3 +15,22 @@ type Array struct {
 func (a *Array) Array() (*Array, error) {
 	return a, nil
 }
+
+//Value returns the underlying Array's value
+func (a *Array) Value() []Item {
+	return a.val
+}
+
+// NewArray returns a new Array.
+func NewArray(val []Item) *Array {
+	return &Array{
+		&abstractItem{},
+		val,
+	}
+}
+
+// Hash overrides the default abstract hash method.
+func (a *Array) Hash() (string, error) {
+	data := fmt.Sprintf("%T %v", a, a.Value())
+	return KeyGenerator([]byte(data))
+}

pkg/vm/stack/boolean.go

@@ -1,5 +1,9 @@
 package stack
 
+import (
+	"fmt"
+)
+
 // Boolean represents a boolean value on the stack
 type Boolean struct {
 	*abstractItem
@@ -44,3 +48,9 @@ func (b *Boolean) Or(a *Boolean) *Boolean {
 	c := b.Value() || a.Value()
 	return NewBoolean(c)
 }
+
+// Hash overrides the default abstract hash method.
+func (b *Boolean) Hash() (string, error) {
+	data := fmt.Sprintf("%T %v", b, b.Value())
+	return KeyGenerator([]byte(data))
+}

pkg/vm/stack/bytearray.go

@@ -3,6 +3,7 @@ package stack
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"math/big"
 	"strconv"
 )
@@ -69,3 +70,14 @@ func reverse(b []byte) []byte {
 
 	return dest
 }
+
+//Value returns the underlying ByteArray's value.
+func (ba *ByteArray) Value() []byte {
+	return ba.val
+}
+
+// Hash overrides the default abstract hash method.
+func (ba *ByteArray) Hash() (string, error) {
+	data := fmt.Sprintf("%T %v", ba, ba.Value())
+	return KeyGenerator([]byte(data))
+}

pkg/vm/stack/context.go

@@ -3,6 +3,7 @@ package stack
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 )
 
 // Context represent the current execution context of the VM.
@@ -150,3 +151,9 @@ func (c *Context) readVarBytes() ([]byte, error) {
 	}
 	return c.ReadBytes(int(n))
 }
+
+// Hash overrides the default abstract hash method.
+func (c *Context) Hash() (string, error) {
+	data := c.String() + fmt.Sprintf(" %v-%v-%v-%v-%v", c.ip, c.prog, c.breakPoints, c.Estack, c.Astack)
+	return KeyGenerator([]byte(data))
+}

pkg/vm/stack/map.go

@@ -0,0 +1,166 @@
+package stack
+
+import (
+	"errors"
+	"fmt"
+	"sort"
+
+	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
+)
+
+// Map represents a map of key, value pair on the stack.
+// Both key and value are stack Items.
+type Map struct {
+	*abstractItem
+	val map[Item]Item
+}
+
+// NewMap returns a Map stack Item given
+// a map whose keys and values are stack Items.
+func NewMap(val map[Item]Item) (*Map, error) {
+	return &Map{
+		abstractItem: &abstractItem{},
+		val:          val,
+	}, nil
+}
+
+// Map will overwrite the default implementation
+// to allow go to cast this item as an Map.
+func (m *Map) Map() (*Map, error) {
+	return m, nil
+}
+
+// Boolean overrides the default Boolean method
+// to convert an Map into a Boolean StackItem
+func (m *Map) Boolean() (*Boolean, error) {
+	return NewBoolean(true), nil
+}
+
+// ContainsKey returns a boolean whose value is true
+// iff the underlying map value contains the Item i
+// as a key.
+func (m *Map) ContainsKey(key Item) (*Boolean, error) {
+	for k := range m.Value() {
+		if ok, err := CompareHash(k, key); err != nil {
+			return nil, err
+		} else if ok.Value() == true {
+			return ok, nil
+		}
+
+	}
+	return NewBoolean(false), nil
+}
+
+// Value returns the underlying map's value
+func (m *Map) Value() map[Item]Item {
+	return m.val
+}
+
+// Remove removes the Item i from the
+// underlying map's value.
+func (m *Map) Remove(key Item) error {
+	var d Item
+	for k := range m.Value() {
+		if ok, err := CompareHash(k, key); err != nil {
+			return err
+		} else if ok.Value() == true {
+			d = k
+		}
+
+	}
+	if d != nil {
+		delete(m.Value(), d)
+	}
+	return nil
+}
+
+// Add inserts a new key, value pair of Items into
+// the underlying map's value.
+func (m *Map) Add(key Item, value Item) error {
+	for k := range m.Value() {
+		if ok, err := CompareHash(k, key); err != nil {
+			return err
+		} else if ok.Value() == true {
+			return errors.New("try to insert duplicate key! ")
+		}
+	}
+	m.Value()[key] = value
+	return nil
+}
+
+// ValueOfKey tries to get the value of the key Item
+// from the map's underlying value.
+func (m *Map) ValueOfKey(key Item) (Item, error) {
+	for k, v := range m.Value() {
+		if ok, err := CompareHash(k, key); err != nil {
+			return nil, err
+		} else if ok.Value() == true {
+			return v, nil
+		}
+
+	}
+	return nil, nil
+
+}
+
+// Clear empties the the underlying map's value.
+func (m *Map) Clear() {
+	m.val = map[Item]Item{}
+}
+
+// CompareHash compare the the Hashes of two items.
+// If they are equal it returns a true boolean. Otherwise
+// it returns  false boolean. Item whose hashes are equal are
+// to be considered equal.
+func CompareHash(i1 Item, i2 Item) (*Boolean, error) {
+	hash1, err := i1.Hash()
+	if err != nil {
+		return nil, err
+	}
+	hash2, err := i2.Hash()
+	if err != nil {
+		return nil, err
+	}
+	if hash1 == hash2 {
+		return NewBoolean(true), nil
+	}
+
+	return NewBoolean(false), nil
+}
+
+// Hash overrides the default abstract hash method.
+func (m *Map) Hash() (string, error) {
+	var hashSlice sort.StringSlice = []string{}
+	var data = fmt.Sprintf("%T ", m)
+
+	for k, v := range m.Value() {
+		hk, err := k.Hash()
+		if err != nil {
+			return "", err
+		}
+		hv, err := v.Hash()
+
+		if err != nil {
+			return "", err
+		}
+
+		hashSlice = append(hashSlice, hk)
+		hashSlice = append(hashSlice, hv)
+	}
+	hashSlice.Sort()
+
+	for _, h := range hashSlice {
+		data += h
+	}
+
+	return KeyGenerator([]byte(data))
+}
+
+// KeyGenerator hashes a byte slice to obtain a unique identifier.
+func KeyGenerator(data []byte) (string, error) {
+	h, err := hash.Sha256([]byte(data))
+	if err != nil {
+		return "", err
+	}
+	return h.String(), nil
+}

pkg/vm/stack/map_test.go

@@ -0,0 +1,141 @@
+package stack
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMap(t *testing.T) {
+	// define Map m for testing
+	var a Item = testMakeStackInt(t, 10)
+	var b Item = NewBoolean(true)
+	var c Item = NewByteArray([]byte{1, 2, 34})
+	var d Item = testMakeStackMap(t, map[Item]Item{
+		a: c,
+		b: a,
+	})
+	var e = NewContext([]byte{1, 2, 3, 4})
+	var f = NewArray([]Item{a, b})
+
+	val := map[Item]Item{
+		a: c,
+		b: a,
+		c: b,
+		d: a,
+		e: d,
+		f: e,
+	}
+	m := testMakeStackMap(t, val)
+
+	// test ValueOfKey
+	valueA, _ := m.ValueOfKey(testMakeStackInt(t, 10))
+	assert.Equal(t, c, valueA)
+
+	valueB, _ := m.ValueOfKey(b)
+	assert.Equal(t, a, valueB)
+
+	valueC, _ := m.ValueOfKey(NewByteArray([]byte{1, 2, 34}))
+	assert.Equal(t, b, valueC)
+
+	valueD, _ := m.ValueOfKey(testMakeStackMap(t, map[Item]Item{
+		b: a,
+		a: c,
+	}))
+	assert.Equal(t, a, valueD)
+
+	valueE, _ := m.ValueOfKey(NewContext([]byte{1, 2, 3, 4}))
+	assert.Equal(t, d, valueE)
+
+	valueF, _ := m.ValueOfKey(NewArray([]Item{a, b}))
+	assert.Equal(t, e, valueF)
+
+	valueX, _ := m.ValueOfKey(NewByteArray([]byte{1, 2, 35}))
+	assert.NotEqual(t, b, valueX)
+
+	checkA, err := m.ContainsKey(a)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkA.Value())
+
+	//test ContainsKey
+	checkB, err := m.ContainsKey(b)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkB.Value())
+
+	checkC, err := m.ContainsKey(c)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkC.Value())
+
+	checkD, err := m.ContainsKey(d)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkD.Value())
+
+	checkE, err := m.ContainsKey(e)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkE.Value())
+
+	//test CompareHash
+	val2 := map[Item]Item{
+		f: e,
+		e: d,
+		d: a,
+		c: b,
+		b: a,
+		a: c,
+	}
+	m2 := testMakeStackMap(t, val2)
+	checkMap, err := CompareHash(m, m2)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkMap.Value())
+
+	checkBoolean, err := CompareHash(b, NewBoolean(true))
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkBoolean.Value())
+
+	checkByteArray, err := CompareHash(c, NewByteArray([]byte{1, 2, 34}))
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkByteArray.Value())
+
+	checkContext, err := CompareHash(e, NewContext([]byte{1, 2, 3, 4}))
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkContext.Value())
+
+	checkArray, err := CompareHash(f, NewArray([]Item{a, b}))
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkArray.Value())
+}
+
+func TestMapAdd(t *testing.T) {
+	var a Item = testMakeStackInt(t, 10)
+	var b Item = NewBoolean(true)
+	var m = testMakeStackMap(t, map[Item]Item{})
+
+	err := m.Add(a, a)
+	assert.Nil(t, err)
+	err = m.Add(b, a)
+	assert.Nil(t, err)
+
+	assert.Equal(t, 2, len(m.Value()))
+
+	expected := testMakeStackMap(t, map[Item]Item{b: a, a: a})
+	check, err := CompareHash(m, expected)
+	assert.Nil(t, err)
+	assert.Equal(t, true, check.Value())
+
+}
+
+func TestMapRemove(t *testing.T) {
+	var a Item = testMakeStackInt(t, 10)
+	var b Item = NewBoolean(true)
+	var m = testMakeStackMap(t, map[Item]Item{b: a, a: a})
+
+	err := m.Remove(a)
+	assert.Nil(t, err)
+	assert.Equal(t, 1, len(m.Value()))
+
+	expected := testMakeStackMap(t, map[Item]Item{b: a})
+	check, err := CompareHash(m, expected)
+	assert.Nil(t, err)
+	assert.Equal(t, true, check.Value())
+
+}

pkg/vm/stack/stackitem.go

@@ -11,6 +11,8 @@ type Item interface {
 	ByteArray() (*ByteArray, error)
 	Array() (*Array, error)
 	Context() (*Context, error)
+	Map() (*Map, error)
+	Hash() (string, error)
 }
 
 // Represents an `abstract` stack item
@@ -47,3 +49,13 @@ func (a *abstractItem) Array() (*Array, error) {
 func (a *abstractItem) Context() (*Context, error) {
 	return nil, errors.New("This stack item is not of type context")
 }
+
+// Context is the default implementation for a stackItem
+// Implements Item interface
+func (a *abstractItem) Map() (*Map, error) {
+	return nil, errors.New("This stack item is not a map")
+}
+
+func (a *abstractItem) Hash() (string, error) {
+	return "", errors.New("This stack item need to override the Hash Method")
+}

pkg/vm/stack/test_helper.go

@@ -42,3 +42,15 @@ func testReadInt64(data []byte) int64 {
 	binary.Read(buf, binary.LittleEndian, &ret)
 	return ret
 }
+
+func testMakeStackMap(t *testing.T, m map[Item]Item) *Map {
+	a, err := NewMap(m)
+	assert.Nil(t, err)
+	return a
+}
+
+func testArray(t *testing.T, m map[Item]Item) *Map {
+	a, err := NewMap(m)
+	assert.Nil(t, err)
+	return a
+}

pkg/vm/vm_ops.go

@@ -9,6 +9,9 @@ var opFunc = map[stack.Instruction]stackInfo{
 	stack.OR:          Or,
 	stack.AND:         And,
 	stack.INVERT:      Invert,
+	stack.MIN:         Min,
+	stack.MAX:         Max,
+	stack.WITHIN:      Within,
 	stack.NUMEQUAL:    NumEqual,
 	stack.NUMNOTEQUAL: NumNotEqual,
 	stack.BOOLAND:     BoolAnd,

pkg/vm/vm_ops_maths.go

@@ -205,6 +205,54 @@ func NumNotEqual(op stack.Instruction, ctx *stack.Context, istack *stack.Invocat
 	return NONE, nil
 }
 
+// Min pops two integers, a and b, off of the stack and pushes an integer to the stack
+// whose value is is the minum between a and b's value.
+// Returns an error if either items cannot be casted to an integer
+func Min(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	operandA, operandB, err := popTwoIntegers(ctx)
+	if err != nil {
+		return FAULT, err
+	}
+	res := stack.Min(operandA, operandB)
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// Max pops two integers, a and b, off of the stack and pushes an integer to the stack
+// whose value is is the maximum between a and b's value.
+// Returns an error if either items cannot be casted to an integer
+func Max(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	operandA, operandB, err := popTwoIntegers(ctx)
+	if err != nil {
+		return FAULT, err
+	}
+	res := stack.Max(operandA, operandB)
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// Within pops three integers, a, b, and c off of the stack and pushes a boolean to the stack
+// whose value is true iff c's value is within b's value (include) and a's value.
+// Returns an error if at least one item cannot be casted to an boolean.
+func Within(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	a, b, c, err := popThreeIntegers(ctx)
+	if err != nil {
+		return FAULT, err
+	}
+	res := stack.NewBoolean(c.Within(b, a))
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
 // Abs pops an integer off of the stack and pushes its absolute value onto the stack.
 // Returns an error if the popped value is not an integer or if the absolute value cannot be taken
 func Abs(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
@@ -434,6 +482,23 @@ func popTwoIntegers(ctx *stack.Context) (*stack.Int, *stack.Int, error) {
 	return operandA, operandB, nil
 }
 
+func popThreeIntegers(ctx *stack.Context) (*stack.Int, *stack.Int, *stack.Int, error) {
+	operandA, err := ctx.Estack.PopInt()
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	operandB, err := ctx.Estack.PopInt()
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	operandC, err := ctx.Estack.PopInt()
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	return operandA, operandB, operandC, nil
+}
+
 func popTwoByteArrays(ctx *stack.Context) (*stack.ByteArray, *stack.ByteArray, error) {
 	// Pop first stack item and cast as byte array
 	ba1, err := ctx.Estack.PopByteArray()

pkg/vm/vm_ops_maths_test.go

@@ -13,9 +13,7 @@ func TestIncOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -26,9 +24,7 @@ func TestIncOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(21), item.Value().Int64())
 }
@@ -38,9 +34,7 @@ func TestDecOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -51,9 +45,7 @@ func TestDecOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(19), item.Value().Int64())
 }
@@ -63,13 +55,10 @@ func TestAddOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
+
-	}
 	b, err := stack.NewInt(big.NewInt(23))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -80,9 +69,7 @@ func TestAddOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(43), item.Value().Int64())
 
@@ -93,13 +80,10 @@ func TestSubOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(30))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
+
-	}
 	b, err := stack.NewInt(big.NewInt(40))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -110,9 +94,7 @@ func TestSubOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(-10), item.Value().Int64())
 
@@ -123,13 +105,10 @@ func TestDivOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(10))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
+
-	}
 	b, err := stack.NewInt(big.NewInt(4))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -140,9 +119,7 @@ func TestDivOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(2), item.Value().Int64())
 }
@@ -152,13 +129,10 @@ func TestModOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(15))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
+
-	}
 	b, err := stack.NewInt(big.NewInt(4))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -169,9 +143,7 @@ func TestModOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(3), item.Value().Int64())
 }
@@ -181,9 +153,7 @@ func TestNzOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -194,9 +164,7 @@ func TestNzOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, true, item.Value())
 }
@@ -206,13 +174,10 @@ func TestMulOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
+
-	}
 	b, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -223,9 +188,7 @@ func TestMulOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(400), item.Value().Int64())
 }
@@ -235,9 +198,7 @@ func TestAbsOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(-20))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -248,9 +209,7 @@ func TestAbsOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(20), item.Value().Int64())
 }
@@ -270,9 +229,7 @@ func TestNotOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, true, item.Value())
 }
@@ -282,13 +239,10 @@ func TestNumEqual(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(6))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
+
-	}
 	b, err := stack.NewInt(big.NewInt(6))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -299,9 +253,7 @@ func TestNumEqual(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, true, item.Value())
 }
@@ -311,13 +263,10 @@ func TestNumNotEqual(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(5))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
+
-	}
 	b, err := stack.NewInt(big.NewInt(6))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -328,9 +277,7 @@ func TestNumNotEqual(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, true, item.Value())
 }
@@ -340,9 +287,7 @@ func TestSignOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(-20))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -353,9 +298,7 @@ func TestSignOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(-1), item.Value().Int64())
 }
@@ -365,9 +308,7 @@ func TestNegateOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(-20))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -378,9 +319,7 @@ func TestNegateOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(20), item.Value().Int64())
 }
@@ -448,13 +387,10 @@ func TestShlOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(2))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
+
-	}
 	b, err := stack.NewInt(big.NewInt(3))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -470,9 +406,7 @@ func TestShlOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(16), item.Value().Int64())
 }
@@ -482,13 +416,10 @@ func TestShrOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(10))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
+
-	}
 	b, err := stack.NewInt(big.NewInt(2))
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -504,9 +435,7 @@ func TestShrOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, int64(2), item.Value().Int64())
 }
@@ -527,9 +456,7 @@ func TestBoolAndOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, true, item.Value())
 }
@@ -550,9 +477,7 @@ func TestBoolOrOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Fail()
-	}
 
 	assert.Equal(t, true, item.Value())
 }
@@ -562,10 +487,10 @@ func TestLtOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(10))
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	b, err := stack.NewInt(big.NewInt(2))
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -581,7 +506,7 @@ func TestLtOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	assert.Equal(t, false, item.Value())
 }
@@ -591,10 +516,10 @@ func TestGtOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(10))
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	b, err := stack.NewInt(big.NewInt(2))
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -610,7 +535,89 @@ func TestGtOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	assert.NoError(t, err)
+	assert.Nil(t, err)
+
+	assert.Equal(t, true, item.Value())
+}
+
+func TestMinOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	v.executeOp(stack.MIN, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(2), item.Value().Int64())
+}
+
+func TestMaxOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	v.executeOp(stack.MAX, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(10), item.Value().Int64())
+}
+
+func TestWithinOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(5))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	c, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b).Push(c)
+
+	// c is the first item popped.
+	// b is the second item popped.
+	// a is the third item popped.
+	// if a is within [b, c) we place a boolean,
+	// whose value is true, on top of the evaluation
+	// stack. Otherwise we place a boolean with
+	// false value.
+	v.executeOp(stack.WITHIN, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopBoolean()
+	assert.Nil(t, err)
 
 	assert.Equal(t, true, item.Value())
 }