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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 13:14:23 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 13:14:23 +0000 |
commit | 73df946d56c74384511a194dd01dbe099584fd1a (patch) | |
tree | fd0bcea490dd81327ddfbb31e215439672c9a068 /src/testing/quick/quick.go | |
parent | Initial commit. (diff) | |
download | golang-1.16-upstream.tar.xz golang-1.16-upstream.zip |
Adding upstream version 1.16.10.upstream/1.16.10upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/testing/quick/quick.go')
-rw-r--r-- | src/testing/quick/quick.go | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/src/testing/quick/quick.go b/src/testing/quick/quick.go new file mode 100644 index 0000000..c01647e --- /dev/null +++ b/src/testing/quick/quick.go @@ -0,0 +1,385 @@ +// 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.Ptr: + 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 []interface{} +} + +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 []interface{} + Out2 []interface{} +} + +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 interface{}, 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 interface{}, 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 interface{}) (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) []interface{} { + ret := make([]interface{}, len(values)) + for i, v := range values { + ret[i] = v.Interface() + } + return ret +} + +func toString(interfaces []interface{}) string { + s := make([]string, len(interfaces)) + for i, v := range interfaces { + s[i] = fmt.Sprintf("%#v", v) + } + return strings.Join(s, ", ") +} |