btcd/txscript/stack_test.go
Dave Collins fdc2bc867b
txscript: Significantly improve errors.
This converts the majority of script errors from generic errors created
via errors.New and fmt.Errorf to use a concrete type that implements the
error interface with an error code and description.

This allows callers to programmatically detect the type of error via
type assertions and an error code while still allowing the errors to
provide more context.

For example, instead of just having an error the reads "disabled opcode"
as would happen prior to these changes when a disabled opcode is
encountered, the error will now read "attempt to execute disabled opcode
OP_FOO".

While it was previously possible to programmatically detect many errors
due to them being exported, they provided no additional context and
there were also various instances that were just returning errors
created on the spot which callers could not reliably detect without
resorting to looking at the actual error message, which is nearly always
bad practice.

Also, while here, export the MaxStackSize and MaxScriptSize constants
since they can be useful for consumers of the package and perform some
minor cleanup of some of the tests.
2017-01-12 13:12:39 -06:00

951 lines
16 KiB
Go

// Copyright (c) 2013-2017 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package txscript
import (
"bytes"
"errors"
"fmt"
"reflect"
"testing"
)
// tstCheckScriptError ensures the type of the two passed errors are of the
// same type (either both nil or both of type Error) and their error codes
// match when not nil.
func tstCheckScriptError(gotErr, wantErr error) error {
// Ensure the error code is of the expected type and the error
// code matches the value specified in the test instance.
if reflect.TypeOf(gotErr) != reflect.TypeOf(wantErr) {
return fmt.Errorf("wrong error - got %T (%[1]v), want %T",
gotErr, wantErr)
}
if gotErr == nil {
return nil
}
// Ensure the want error type is a script error.
werr, ok := wantErr.(Error)
if !ok {
return fmt.Errorf("unexpected test error type %T", wantErr)
}
// Ensure the error codes match. It's safe to use a raw type assert
// here since the code above already proved they are the same type and
// the want error is a script error.
gotErrorCode := gotErr.(Error).ErrorCode
if gotErrorCode != werr.ErrorCode {
return fmt.Errorf("mismatched error code - got %v (%v), want %v",
gotErrorCode, gotErr, werr.ErrorCode)
}
return nil
}
// TestStack tests that all of the stack operations work as expected.
func TestStack(t *testing.T) {
t.Parallel()
tests := []struct {
name string
before [][]byte
operation func(*stack) error
err error
after [][]byte
}{
{
"noop",
[][]byte{{1}, {2}, {3}, {4}, {5}},
func(s *stack) error {
return nil
},
nil,
[][]byte{{1}, {2}, {3}, {4}, {5}},
},
{
"peek underflow (byte)",
[][]byte{{1}, {2}, {3}, {4}, {5}},
func(s *stack) error {
_, err := s.PeekByteArray(5)
return err
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"peek underflow (int)",
[][]byte{{1}, {2}, {3}, {4}, {5}},
func(s *stack) error {
_, err := s.PeekInt(5)
return err
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"peek underflow (bool)",
[][]byte{{1}, {2}, {3}, {4}, {5}},
func(s *stack) error {
_, err := s.PeekBool(5)
return err
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"pop",
[][]byte{{1}, {2}, {3}, {4}, {5}},
func(s *stack) error {
val, err := s.PopByteArray()
if err != nil {
return err
}
if !bytes.Equal(val, []byte{5}) {
return errors.New("not equal")
}
return err
},
nil,
[][]byte{{1}, {2}, {3}, {4}},
},
{
"pop everything",
[][]byte{{1}, {2}, {3}, {4}, {5}},
func(s *stack) error {
for i := 0; i < 5; i++ {
_, err := s.PopByteArray()
if err != nil {
return err
}
}
return nil
},
nil,
nil,
},
{
"pop underflow",
[][]byte{{1}, {2}, {3}, {4}, {5}},
func(s *stack) error {
for i := 0; i < 6; i++ {
_, err := s.PopByteArray()
if err != nil {
return err
}
}
return nil
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"pop bool",
[][]byte{nil},
func(s *stack) error {
val, err := s.PopBool()
if err != nil {
return err
}
if val {
return errors.New("unexpected value")
}
return nil
},
nil,
nil,
},
{
"pop bool",
[][]byte{{1}},
func(s *stack) error {
val, err := s.PopBool()
if err != nil {
return err
}
if !val {
return errors.New("unexpected value")
}
return nil
},
nil,
nil,
},
{
"pop bool",
nil,
func(s *stack) error {
_, err := s.PopBool()
return err
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"popInt 0",
[][]byte{{0x0}},
func(s *stack) error {
v, err := s.PopInt()
if err != nil {
return err
}
if v != 0 {
return errors.New("0 != 0 on popInt")
}
return nil
},
nil,
nil,
},
{
"popInt -0",
[][]byte{{0x80}},
func(s *stack) error {
v, err := s.PopInt()
if err != nil {
return err
}
if v != 0 {
return errors.New("-0 != 0 on popInt")
}
return nil
},
nil,
nil,
},
{
"popInt 1",
[][]byte{{0x01}},
func(s *stack) error {
v, err := s.PopInt()
if err != nil {
return err
}
if v != 1 {
return errors.New("1 != 1 on popInt")
}
return nil
},
nil,
nil,
},
{
"popInt 1 leading 0",
[][]byte{{0x01, 0x00, 0x00, 0x00}},
func(s *stack) error {
v, err := s.PopInt()
if err != nil {
return err
}
if v != 1 {
fmt.Printf("%v != %v\n", v, 1)
return errors.New("1 != 1 on popInt")
}
return nil
},
nil,
nil,
},
{
"popInt -1",
[][]byte{{0x81}},
func(s *stack) error {
v, err := s.PopInt()
if err != nil {
return err
}
if v != -1 {
return errors.New("-1 != -1 on popInt")
}
return nil
},
nil,
nil,
},
{
"popInt -1 leading 0",
[][]byte{{0x01, 0x00, 0x00, 0x80}},
func(s *stack) error {
v, err := s.PopInt()
if err != nil {
return err
}
if v != -1 {
fmt.Printf("%v != %v\n", v, -1)
return errors.New("-1 != -1 on popInt")
}
return nil
},
nil,
nil,
},
// Triggers the multibyte case in asInt
{
"popInt -513",
[][]byte{{0x1, 0x82}},
func(s *stack) error {
v, err := s.PopInt()
if err != nil {
return err
}
if v != -513 {
fmt.Printf("%v != %v\n", v, -513)
return errors.New("1 != 1 on popInt")
}
return nil
},
nil,
nil,
},
// Confirm that the asInt code doesn't modify the base data.
{
"peekint nomodify -1",
[][]byte{{0x01, 0x00, 0x00, 0x80}},
func(s *stack) error {
v, err := s.PeekInt(0)
if err != nil {
return err
}
if v != -1 {
fmt.Printf("%v != %v\n", v, -1)
return errors.New("-1 != -1 on popInt")
}
return nil
},
nil,
[][]byte{{0x01, 0x00, 0x00, 0x80}},
},
{
"PushInt 0",
nil,
func(s *stack) error {
s.PushInt(scriptNum(0))
return nil
},
nil,
[][]byte{{}},
},
{
"PushInt 1",
nil,
func(s *stack) error {
s.PushInt(scriptNum(1))
return nil
},
nil,
[][]byte{{0x1}},
},
{
"PushInt -1",
nil,
func(s *stack) error {
s.PushInt(scriptNum(-1))
return nil
},
nil,
[][]byte{{0x81}},
},
{
"PushInt two bytes",
nil,
func(s *stack) error {
s.PushInt(scriptNum(256))
return nil
},
nil,
// little endian.. *sigh*
[][]byte{{0x00, 0x01}},
},
{
"PushInt leading zeros",
nil,
func(s *stack) error {
// this will have the highbit set
s.PushInt(scriptNum(128))
return nil
},
nil,
[][]byte{{0x80, 0x00}},
},
{
"dup",
[][]byte{{1}},
func(s *stack) error {
return s.DupN(1)
},
nil,
[][]byte{{1}, {1}},
},
{
"dup2",
[][]byte{{1}, {2}},
func(s *stack) error {
return s.DupN(2)
},
nil,
[][]byte{{1}, {2}, {1}, {2}},
},
{
"dup3",
[][]byte{{1}, {2}, {3}},
func(s *stack) error {
return s.DupN(3)
},
nil,
[][]byte{{1}, {2}, {3}, {1}, {2}, {3}},
},
{
"dup0",
[][]byte{{1}},
func(s *stack) error {
return s.DupN(0)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"dup-1",
[][]byte{{1}},
func(s *stack) error {
return s.DupN(-1)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"dup too much",
[][]byte{{1}},
func(s *stack) error {
return s.DupN(2)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"PushBool true",
nil,
func(s *stack) error {
s.PushBool(true)
return nil
},
nil,
[][]byte{{1}},
},
{
"PushBool false",
nil,
func(s *stack) error {
s.PushBool(false)
return nil
},
nil,
[][]byte{nil},
},
{
"PushBool PopBool",
nil,
func(s *stack) error {
s.PushBool(true)
val, err := s.PopBool()
if err != nil {
return err
}
if !val {
return errors.New("unexpected value")
}
return nil
},
nil,
nil,
},
{
"PushBool PopBool 2",
nil,
func(s *stack) error {
s.PushBool(false)
val, err := s.PopBool()
if err != nil {
return err
}
if val {
return errors.New("unexpected value")
}
return nil
},
nil,
nil,
},
{
"PushInt PopBool",
nil,
func(s *stack) error {
s.PushInt(scriptNum(1))
val, err := s.PopBool()
if err != nil {
return err
}
if !val {
return errors.New("unexpected value")
}
return nil
},
nil,
nil,
},
{
"PushInt PopBool 2",
nil,
func(s *stack) error {
s.PushInt(scriptNum(0))
val, err := s.PopBool()
if err != nil {
return err
}
if val {
return errors.New("unexpected value")
}
return nil
},
nil,
nil,
},
{
"Nip top",
[][]byte{{1}, {2}, {3}},
func(s *stack) error {
return s.NipN(0)
},
nil,
[][]byte{{1}, {2}},
},
{
"Nip middle",
[][]byte{{1}, {2}, {3}},
func(s *stack) error {
return s.NipN(1)
},
nil,
[][]byte{{1}, {3}},
},
{
"Nip low",
[][]byte{{1}, {2}, {3}},
func(s *stack) error {
return s.NipN(2)
},
nil,
[][]byte{{2}, {3}},
},
{
"Nip too much",
[][]byte{{1}, {2}, {3}},
func(s *stack) error {
// bite off more than we can chew
return s.NipN(3)
},
scriptError(ErrInvalidStackOperation, ""),
[][]byte{{2}, {3}},
},
{
"keep on tucking",
[][]byte{{1}, {2}, {3}},
func(s *stack) error {
return s.Tuck()
},
nil,
[][]byte{{1}, {3}, {2}, {3}},
},
{
"a little tucked up",
[][]byte{{1}}, // too few arguments for tuck
func(s *stack) error {
return s.Tuck()
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"all tucked up",
nil, // too few arguments for tuck
func(s *stack) error {
return s.Tuck()
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"drop 1",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.DropN(1)
},
nil,
[][]byte{{1}, {2}, {3}},
},
{
"drop 2",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.DropN(2)
},
nil,
[][]byte{{1}, {2}},
},
{
"drop 3",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.DropN(3)
},
nil,
[][]byte{{1}},
},
{
"drop 4",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.DropN(4)
},
nil,
nil,
},
{
"drop 4/5",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.DropN(5)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"drop invalid",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.DropN(0)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"Rot1",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.RotN(1)
},
nil,
[][]byte{{1}, {3}, {4}, {2}},
},
{
"Rot2",
[][]byte{{1}, {2}, {3}, {4}, {5}, {6}},
func(s *stack) error {
return s.RotN(2)
},
nil,
[][]byte{{3}, {4}, {5}, {6}, {1}, {2}},
},
{
"Rot too little",
[][]byte{{1}, {2}},
func(s *stack) error {
return s.RotN(1)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"Rot0",
[][]byte{{1}, {2}, {3}},
func(s *stack) error {
return s.RotN(0)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"Swap1",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.SwapN(1)
},
nil,
[][]byte{{1}, {2}, {4}, {3}},
},
{
"Swap2",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.SwapN(2)
},
nil,
[][]byte{{3}, {4}, {1}, {2}},
},
{
"Swap too little",
[][]byte{{1}},
func(s *stack) error {
return s.SwapN(1)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"Swap0",
[][]byte{{1}, {2}, {3}},
func(s *stack) error {
return s.SwapN(0)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"Over1",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.OverN(1)
},
nil,
[][]byte{{1}, {2}, {3}, {4}, {3}},
},
{
"Over2",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.OverN(2)
},
nil,
[][]byte{{1}, {2}, {3}, {4}, {1}, {2}},
},
{
"Over too little",
[][]byte{{1}},
func(s *stack) error {
return s.OverN(1)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"Over0",
[][]byte{{1}, {2}, {3}},
func(s *stack) error {
return s.OverN(0)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"Pick1",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.PickN(1)
},
nil,
[][]byte{{1}, {2}, {3}, {4}, {3}},
},
{
"Pick2",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.PickN(2)
},
nil,
[][]byte{{1}, {2}, {3}, {4}, {2}},
},
{
"Pick too little",
[][]byte{{1}},
func(s *stack) error {
return s.PickN(1)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"Roll1",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.RollN(1)
},
nil,
[][]byte{{1}, {2}, {4}, {3}},
},
{
"Roll2",
[][]byte{{1}, {2}, {3}, {4}},
func(s *stack) error {
return s.RollN(2)
},
nil,
[][]byte{{1}, {3}, {4}, {2}},
},
{
"Roll too little",
[][]byte{{1}},
func(s *stack) error {
return s.RollN(1)
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
{
"Peek bool",
[][]byte{{1}},
func(s *stack) error {
// Peek bool is otherwise pretty well tested,
// just check it works.
val, err := s.PeekBool(0)
if err != nil {
return err
}
if !val {
return errors.New("invalid result")
}
return nil
},
nil,
[][]byte{{1}},
},
{
"Peek bool 2",
[][]byte{nil},
func(s *stack) error {
// Peek bool is otherwise pretty well tested,
// just check it works.
val, err := s.PeekBool(0)
if err != nil {
return err
}
if val {
return errors.New("invalid result")
}
return nil
},
nil,
[][]byte{nil},
},
{
"Peek int",
[][]byte{{1}},
func(s *stack) error {
// Peek int is otherwise pretty well tested,
// just check it works.
val, err := s.PeekInt(0)
if err != nil {
return err
}
if val != 1 {
return errors.New("invalid result")
}
return nil
},
nil,
[][]byte{{1}},
},
{
"Peek int 2",
[][]byte{{0}},
func(s *stack) error {
// Peek int is otherwise pretty well tested,
// just check it works.
val, err := s.PeekInt(0)
if err != nil {
return err
}
if val != 0 {
return errors.New("invalid result")
}
return nil
},
nil,
[][]byte{{0}},
},
{
"pop int",
nil,
func(s *stack) error {
s.PushInt(scriptNum(1))
// Peek int is otherwise pretty well tested,
// just check it works.
val, err := s.PopInt()
if err != nil {
return err
}
if val != 1 {
return errors.New("invalid result")
}
return nil
},
nil,
nil,
},
{
"pop empty",
nil,
func(s *stack) error {
// Peek int is otherwise pretty well tested,
// just check it works.
_, err := s.PopInt()
return err
},
scriptError(ErrInvalidStackOperation, ""),
nil,
},
}
for _, test := range tests {
// Setup the initial stack state and perform the test operation.
s := stack{}
for i := range test.before {
s.PushByteArray(test.before[i])
}
err := test.operation(&s)
// Ensure the error code is of the expected type and the error
// code matches the value specified in the test instance.
if e := tstCheckScriptError(err, test.err); e != nil {
t.Errorf("%s: %v", test.name, e)
continue
}
if err != nil {
continue
}
// Ensure the resulting stack is the expected length.
if int32(len(test.after)) != s.Depth() {
t.Errorf("%s: stack depth doesn't match expected: %v "+
"vs %v", test.name, len(test.after),
s.Depth())
continue
}
// Ensure all items of the resulting stack are the expected
// values.
for i := range test.after {
val, err := s.PeekByteArray(s.Depth() - int32(i) - 1)
if err != nil {
t.Errorf("%s: can't peek %dth stack entry: %v",
test.name, i, err)
break
}
if !bytes.Equal(val, test.after[i]) {
t.Errorf("%s: %dth stack entry doesn't match "+
"expected: %v vs %v", test.name, i, val,
test.after[i])
break
}
}
}
}