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-rw-r--r--src/testing/quick/quick.go385
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diff --git a/src/testing/quick/quick.go b/src/testing/quick/quick.go
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+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package quick implements utility functions to help with black box testing.
+//
+// The testing/quick package is frozen and is not accepting new features.
+package quick
+
+import (
+ "flag"
+ "fmt"
+ "math"
+ "math/rand"
+ "reflect"
+ "strings"
+ "time"
+)
+
+var defaultMaxCount *int = flag.Int("quickchecks", 100, "The default number of iterations for each check")
+
+// A Generator can generate random values of its own type.
+type Generator interface {
+ // Generate returns a random instance of the type on which it is a
+ // method using the size as a size hint.
+ Generate(rand *rand.Rand, size int) reflect.Value
+}
+
+// randFloat32 generates a random float taking the full range of a float32.
+func randFloat32(rand *rand.Rand) float32 {
+ f := rand.Float64() * math.MaxFloat32
+ if rand.Int()&1 == 1 {
+ f = -f
+ }
+ return float32(f)
+}
+
+// randFloat64 generates a random float taking the full range of a float64.
+func randFloat64(rand *rand.Rand) float64 {
+ f := rand.Float64() * math.MaxFloat64
+ if rand.Int()&1 == 1 {
+ f = -f
+ }
+ return f
+}
+
+// randInt64 returns a random int64.
+func randInt64(rand *rand.Rand) int64 {
+ return int64(rand.Uint64())
+}
+
+// complexSize is the maximum length of arbitrary values that contain other
+// values.
+const complexSize = 50
+
+// Value returns an arbitrary value of the given type.
+// If the type implements the Generator interface, that will be used.
+// Note: To create arbitrary values for structs, all the fields must be exported.
+func Value(t reflect.Type, rand *rand.Rand) (value reflect.Value, ok bool) {
+ return sizedValue(t, rand, complexSize)
+}
+
+// sizedValue returns an arbitrary value of the given type. The size
+// hint is used for shrinking as a function of indirection level so
+// that recursive data structures will terminate.
+func sizedValue(t reflect.Type, rand *rand.Rand, size int) (value reflect.Value, ok bool) {
+ if m, ok := reflect.Zero(t).Interface().(Generator); ok {
+ return m.Generate(rand, size), true
+ }
+
+ v := reflect.New(t).Elem()
+ switch concrete := t; concrete.Kind() {
+ case reflect.Bool:
+ v.SetBool(rand.Int()&1 == 0)
+ case reflect.Float32:
+ v.SetFloat(float64(randFloat32(rand)))
+ case reflect.Float64:
+ v.SetFloat(randFloat64(rand))
+ case reflect.Complex64:
+ v.SetComplex(complex(float64(randFloat32(rand)), float64(randFloat32(rand))))
+ case reflect.Complex128:
+ v.SetComplex(complex(randFloat64(rand), randFloat64(rand)))
+ case reflect.Int16:
+ v.SetInt(randInt64(rand))
+ case reflect.Int32:
+ v.SetInt(randInt64(rand))
+ case reflect.Int64:
+ v.SetInt(randInt64(rand))
+ case reflect.Int8:
+ v.SetInt(randInt64(rand))
+ case reflect.Int:
+ v.SetInt(randInt64(rand))
+ case reflect.Uint16:
+ v.SetUint(uint64(randInt64(rand)))
+ case reflect.Uint32:
+ v.SetUint(uint64(randInt64(rand)))
+ case reflect.Uint64:
+ v.SetUint(uint64(randInt64(rand)))
+ case reflect.Uint8:
+ v.SetUint(uint64(randInt64(rand)))
+ case reflect.Uint:
+ v.SetUint(uint64(randInt64(rand)))
+ case reflect.Uintptr:
+ v.SetUint(uint64(randInt64(rand)))
+ case reflect.Map:
+ numElems := rand.Intn(size)
+ v.Set(reflect.MakeMap(concrete))
+ for i := 0; i < numElems; i++ {
+ key, ok1 := sizedValue(concrete.Key(), rand, size)
+ value, ok2 := sizedValue(concrete.Elem(), rand, size)
+ if !ok1 || !ok2 {
+ return reflect.Value{}, false
+ }
+ v.SetMapIndex(key, value)
+ }
+ case reflect.Pointer:
+ if rand.Intn(size) == 0 {
+ v.Set(reflect.Zero(concrete)) // Generate nil pointer.
+ } else {
+ elem, ok := sizedValue(concrete.Elem(), rand, size)
+ if !ok {
+ return reflect.Value{}, false
+ }
+ v.Set(reflect.New(concrete.Elem()))
+ v.Elem().Set(elem)
+ }
+ case reflect.Slice:
+ numElems := rand.Intn(size)
+ sizeLeft := size - numElems
+ v.Set(reflect.MakeSlice(concrete, numElems, numElems))
+ for i := 0; i < numElems; i++ {
+ elem, ok := sizedValue(concrete.Elem(), rand, sizeLeft)
+ if !ok {
+ return reflect.Value{}, false
+ }
+ v.Index(i).Set(elem)
+ }
+ case reflect.Array:
+ for i := 0; i < v.Len(); i++ {
+ elem, ok := sizedValue(concrete.Elem(), rand, size)
+ if !ok {
+ return reflect.Value{}, false
+ }
+ v.Index(i).Set(elem)
+ }
+ case reflect.String:
+ numChars := rand.Intn(complexSize)
+ codePoints := make([]rune, numChars)
+ for i := 0; i < numChars; i++ {
+ codePoints[i] = rune(rand.Intn(0x10ffff))
+ }
+ v.SetString(string(codePoints))
+ case reflect.Struct:
+ n := v.NumField()
+ // Divide sizeLeft evenly among the struct fields.
+ sizeLeft := size
+ if n > sizeLeft {
+ sizeLeft = 1
+ } else if n > 0 {
+ sizeLeft /= n
+ }
+ for i := 0; i < n; i++ {
+ elem, ok := sizedValue(concrete.Field(i).Type, rand, sizeLeft)
+ if !ok {
+ return reflect.Value{}, false
+ }
+ v.Field(i).Set(elem)
+ }
+ default:
+ return reflect.Value{}, false
+ }
+
+ return v, true
+}
+
+// A Config structure contains options for running a test.
+type Config struct {
+ // MaxCount sets the maximum number of iterations.
+ // If zero, MaxCountScale is used.
+ MaxCount int
+ // MaxCountScale is a non-negative scale factor applied to the
+ // default maximum.
+ // A count of zero implies the default, which is usually 100
+ // but can be set by the -quickchecks flag.
+ MaxCountScale float64
+ // Rand specifies a source of random numbers.
+ // If nil, a default pseudo-random source will be used.
+ Rand *rand.Rand
+ // Values specifies a function to generate a slice of
+ // arbitrary reflect.Values that are congruent with the
+ // arguments to the function being tested.
+ // If nil, the top-level Value function is used to generate them.
+ Values func([]reflect.Value, *rand.Rand)
+}
+
+var defaultConfig Config
+
+// getRand returns the *rand.Rand to use for a given Config.
+func (c *Config) getRand() *rand.Rand {
+ if c.Rand == nil {
+ return rand.New(rand.NewSource(time.Now().UnixNano()))
+ }
+ return c.Rand
+}
+
+// getMaxCount returns the maximum number of iterations to run for a given
+// Config.
+func (c *Config) getMaxCount() (maxCount int) {
+ maxCount = c.MaxCount
+ if maxCount == 0 {
+ if c.MaxCountScale != 0 {
+ maxCount = int(c.MaxCountScale * float64(*defaultMaxCount))
+ } else {
+ maxCount = *defaultMaxCount
+ }
+ }
+
+ return
+}
+
+// A SetupError is the result of an error in the way that check is being
+// used, independent of the functions being tested.
+type SetupError string
+
+func (s SetupError) Error() string { return string(s) }
+
+// A CheckError is the result of Check finding an error.
+type CheckError struct {
+ Count int
+ In []any
+}
+
+func (s *CheckError) Error() string {
+ return fmt.Sprintf("#%d: failed on input %s", s.Count, toString(s.In))
+}
+
+// A CheckEqualError is the result CheckEqual finding an error.
+type CheckEqualError struct {
+ CheckError
+ Out1 []any
+ Out2 []any
+}
+
+func (s *CheckEqualError) Error() string {
+ return fmt.Sprintf("#%d: failed on input %s. Output 1: %s. Output 2: %s", s.Count, toString(s.In), toString(s.Out1), toString(s.Out2))
+}
+
+// Check looks for an input to f, any function that returns bool,
+// such that f returns false. It calls f repeatedly, with arbitrary
+// values for each argument. If f returns false on a given input,
+// Check returns that input as a *CheckError.
+// For example:
+//
+// func TestOddMultipleOfThree(t *testing.T) {
+// f := func(x int) bool {
+// y := OddMultipleOfThree(x)
+// return y%2 == 1 && y%3 == 0
+// }
+// if err := quick.Check(f, nil); err != nil {
+// t.Error(err)
+// }
+// }
+func Check(f any, config *Config) error {
+ if config == nil {
+ config = &defaultConfig
+ }
+
+ fVal, fType, ok := functionAndType(f)
+ if !ok {
+ return SetupError("argument is not a function")
+ }
+
+ if fType.NumOut() != 1 {
+ return SetupError("function does not return one value")
+ }
+ if fType.Out(0).Kind() != reflect.Bool {
+ return SetupError("function does not return a bool")
+ }
+
+ arguments := make([]reflect.Value, fType.NumIn())
+ rand := config.getRand()
+ maxCount := config.getMaxCount()
+
+ for i := 0; i < maxCount; i++ {
+ err := arbitraryValues(arguments, fType, config, rand)
+ if err != nil {
+ return err
+ }
+
+ if !fVal.Call(arguments)[0].Bool() {
+ return &CheckError{i + 1, toInterfaces(arguments)}
+ }
+ }
+
+ return nil
+}
+
+// CheckEqual looks for an input on which f and g return different results.
+// It calls f and g repeatedly with arbitrary values for each argument.
+// If f and g return different answers, CheckEqual returns a *CheckEqualError
+// describing the input and the outputs.
+func CheckEqual(f, g any, config *Config) error {
+ if config == nil {
+ config = &defaultConfig
+ }
+
+ x, xType, ok := functionAndType(f)
+ if !ok {
+ return SetupError("f is not a function")
+ }
+ y, yType, ok := functionAndType(g)
+ if !ok {
+ return SetupError("g is not a function")
+ }
+
+ if xType != yType {
+ return SetupError("functions have different types")
+ }
+
+ arguments := make([]reflect.Value, xType.NumIn())
+ rand := config.getRand()
+ maxCount := config.getMaxCount()
+
+ for i := 0; i < maxCount; i++ {
+ err := arbitraryValues(arguments, xType, config, rand)
+ if err != nil {
+ return err
+ }
+
+ xOut := toInterfaces(x.Call(arguments))
+ yOut := toInterfaces(y.Call(arguments))
+
+ if !reflect.DeepEqual(xOut, yOut) {
+ return &CheckEqualError{CheckError{i + 1, toInterfaces(arguments)}, xOut, yOut}
+ }
+ }
+
+ return nil
+}
+
+// arbitraryValues writes Values to args such that args contains Values
+// suitable for calling f.
+func arbitraryValues(args []reflect.Value, f reflect.Type, config *Config, rand *rand.Rand) (err error) {
+ if config.Values != nil {
+ config.Values(args, rand)
+ return
+ }
+
+ for j := 0; j < len(args); j++ {
+ var ok bool
+ args[j], ok = Value(f.In(j), rand)
+ if !ok {
+ err = SetupError(fmt.Sprintf("cannot create arbitrary value of type %s for argument %d", f.In(j), j))
+ return
+ }
+ }
+
+ return
+}
+
+func functionAndType(f any) (v reflect.Value, t reflect.Type, ok bool) {
+ v = reflect.ValueOf(f)
+ ok = v.Kind() == reflect.Func
+ if !ok {
+ return
+ }
+ t = v.Type()
+ return
+}
+
+func toInterfaces(values []reflect.Value) []any {
+ ret := make([]any, len(values))
+ for i, v := range values {
+ ret[i] = v.Interface()
+ }
+ return ret
+}
+
+func toString(interfaces []any) string {
+ s := make([]string, len(interfaces))
+ for i, v := range interfaces {
+ s[i] = fmt.Sprintf("%#v", v)
+ }
+ return strings.Join(s, ", ")
+}