README
¶
gofuzz
gofuzz is a library for populating go objects with random values.
This is useful for testing:
- Do your project's objects really serialize/unserialize correctly in all cases?
- Is there an incorrectly formatted object that will cause your project to panic?
Import with import "github.com/google/gofuzz"
You can use it on single variables:
f := fuzz.New()
var myInt int
f.Fuzz(&myInt) // myInt gets a random value.
You can use it on maps:
f := fuzz.New().NilChance(0).NumElements(1, 1)
var myMap map[ComplexKeyType]string
f.Fuzz(&myMap) // myMap will have exactly one element.
Customize the chance of getting a nil pointer:
f := fuzz.New().NilChance(.5)
var fancyStruct struct {
A, B, C, D *string
}
f.Fuzz(&fancyStruct) // About half the pointers should be set.
You can even customize the randomization completely if needed:
type MyEnum string
const (
A MyEnum = "A"
B MyEnum = "B"
)
type MyInfo struct {
Type MyEnum
AInfo *string
BInfo *string
}
f := fuzz.New().NilChance(0).Funcs(
func(e *MyInfo, c fuzz.Continue) {
switch c.Intn(2) {
case 0:
e.Type = A
c.Fuzz(&e.AInfo)
case 1:
e.Type = B
c.Fuzz(&e.BInfo)
}
},
)
var myObject MyInfo
f.Fuzz(&myObject) // Type will correspond to whether A or B info is set.
See more examples in example_test.go.
Happy testing!
Documentation
¶
Overview ¶
Package fuzz is a library for populating go objects with random values.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Continue ¶
type Continue struct {
// For convenience, Continue implements rand.Rand via embedding.
// Use this for generating any randomness if you want your fuzzing
// to be repeatable for a given seed.
*rand.Rand
// contains filtered or unexported fields
}
Continue can be passed to custom fuzzing functions to allow them to use the correct source of randomness and to continue fuzzing their members.
func (Continue) Fuzz ¶
func (c Continue) Fuzz(obj interface{})
Fuzz continues fuzzing obj. obj must be a pointer.
func (Continue) RandString ¶
RandString makes a random string up to 20 characters long. The returned string may include a variety of (valid) UTF-8 encodings.
func (Continue) RandUint64 ¶
RandUint64 makes random 64 bit numbers. Weirdly, rand doesn't have a function that gives you 64 random bits.
type Fuzzer ¶
type Fuzzer struct {
// contains filtered or unexported fields
}
Fuzzer knows how to fill any object with random fields.
func New ¶
func New() *Fuzzer
New returns a new Fuzzer. Customize your Fuzzer further by calling Funcs, RandSource, NilChance, or NumElements in any order.
func (*Fuzzer) Funcs ¶
Funcs adds each entry in fuzzFuncs as a custom fuzzing function.
Each entry in fuzzFuncs must be a function taking two parameters. The first parameter must be a pointer or map. It is the variable that function will fill with random data. The second parameter must be a fuzz.Continue, which will provide a source of randomness and a way to automatically continue fuzzing smaller pieces of the first parameter.
These functions are called sensibly, e.g., if you wanted custom string fuzzing, the function `func(s *string, c fuzz.Continue)` would get called and passed the address of strings. Maps and pointers will always be made/new'd for you, ignoring the NilChange option. For slices, it doesn't make much sense to pre-create them--Fuzzer doesn't know how long you want your slice--so take a pointer to a slice, and make it yourself. (If you don't want your map/pointer type pre-made, take a pointer to it, and make it yourself.) See the examples for a range of custom functions.
func (*Fuzzer) Fuzz ¶
func (f *Fuzzer) Fuzz(obj interface{})
Fuzz recursively fills all of obj's fields with something random. Not safe for cyclic or tree-like structs! obj must be a pointer. Only exported (public) fields can be set (thanks, golang :/ ) Intended for tests, so will panic on bad input or unimplemented fields.
func (*Fuzzer) NilChance ¶
NilChance sets the probability of creating a nil pointer, map, or slice to 'p'. 'p' should be between 0 (no nils) and 1 (all nils), inclusive.
func (*Fuzzer) NumElements ¶
NumElements sets the minimum and maximum number of elements that will be added to a non-nil map or slice.
Source Files