1gofuzz
2======
3
4gofuzz is a library for populating go objects with random values.
5
6[](https://godoc.org/github.com/google/gofuzz)
7[](https://travis-ci.org/google/gofuzz)
8
9This is useful for testing:
10
11* Do your project's objects really serialize/unserialize correctly in all cases?
12* Is there an incorrectly formatted object that will cause your project to panic?
13
14Import with ```import "github.com/google/gofuzz"```
15
16You can use it on single variables:
17```go
18f := fuzz.New()
19var myInt int
20f.Fuzz(&myInt) // myInt gets a random value.
21```
22
23You can use it on maps:
24```go
25f := fuzz.New().NilChance(0).NumElements(1, 1)
26var myMap map[ComplexKeyType]string
27f.Fuzz(&myMap) // myMap will have exactly one element.
28```
29
30Customize the chance of getting a nil pointer:
31```go
32f := fuzz.New().NilChance(.5)
33var fancyStruct struct {
34 A, B, C, D *string
35}
36f.Fuzz(&fancyStruct) // About half the pointers should be set.
37```
38
39You can even customize the randomization completely if needed:
40```go
41type MyEnum string
42const (
43 A MyEnum = "A"
44 B MyEnum = "B"
45)
46type MyInfo struct {
47 Type MyEnum
48 AInfo *string
49 BInfo *string
50}
51
52f := fuzz.New().NilChance(0).Funcs(
53 func(e *MyInfo, c fuzz.Continue) {
54 switch c.Intn(2) {
55 case 0:
56 e.Type = A
57 c.Fuzz(&e.AInfo)
58 case 1:
59 e.Type = B
60 c.Fuzz(&e.BInfo)
61 }
62 },
63)
64
65var myObject MyInfo
66f.Fuzz(&myObject) // Type will correspond to whether A or B info is set.
67```
68
69See more examples in ```example_test.go```.
70
71You can use this library for easier [go-fuzz](https://github.com/dvyukov/go-fuzz)ing.
72go-fuzz provides the user a byte-slice, which should be converted to different inputs
73for the tested function. This library can help convert the byte slice. Consider for
74example a fuzz test for a the function `mypackage.MyFunc` that takes an int arguments:
75```go
76// +build gofuzz
77package mypackage
78
79import fuzz "github.com/google/gofuzz"
80
81func Fuzz(data []byte) int {
82 var i int
83 fuzz.NewFromGoFuzz(data).Fuzz(&i)
84 MyFunc(i)
85 return 0
86}
87```
88
89Happy testing!
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