quick_test.go

// 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 bindata

import (
	"crypto/sha512"
	"hash"
	"math/rand"
	"reflect"
	"testing/quick"
)

const complexSize = 50

// 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().(quick.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.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.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++ {
			if concrete.Field(i).Type.Implements(reflect.TypeOf((*hash.Hash)(nil)).Elem()) {
				if rand.Int()%3 == 0 {
					v.Field(i).Set(reflect.ValueOf(sha512.New()))
				}

				continue
			}
			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
}

// randInt64 returns a random integer taking half the range of an int64.
func randInt64(rand *rand.Rand) int64 { return rand.Int63() - 1<<62 }