README.md
1# Deep Variable Equality for Humans
2
3[](https://goreportcard.com/report/github.com/go-test/deep) [](https://travis-ci.org/go-test/deep) [](https://coveralls.io/github/go-test/deep?branch=master) [](https://godoc.org/github.com/go-test/deep)
4
5This package provides a single function: `deep.Equal`. It's like [reflect.DeepEqual](http://golang.org/pkg/reflect/#DeepEqual) but much friendlier to humans (or any sentient being) for two reason:
6
7* `deep.Equal` returns a list of differences
8* `deep.Equal` does not compare unexported fields (by default)
9
10`reflect.DeepEqual` is good (like all things Golang!), but it's a game of [Hunt the Wumpus](https://en.wikipedia.org/wiki/Hunt_the_Wumpus). For large maps, slices, and structs, finding the difference is difficult.
11
12`deep.Equal` doesn't play games with you, it lists the differences:
13
14```go
15package main_test
16
17import (
18 "testing"
19 "github.com/go-test/deep"
20)
21
22type T struct {
23 Name string
24 Numbers []float64
25}
26
27func TestDeepEqual(t *testing.T) {
28 // Can you spot the difference?
29 t1 := T{
30 Name: "Isabella",
31 Numbers: []float64{1.13459, 2.29343, 3.010100010},
32 }
33 t2 := T{
34 Name: "Isabella",
35 Numbers: []float64{1.13459, 2.29843, 3.010100010},
36 }
37
38 if diff := deep.Equal(t1, t2); diff != nil {
39 t.Error(diff)
40 }
41}
42```
43
44
45```
46$ go test
47--- FAIL: TestDeepEqual (0.00s)
48 main_test.go:25: [Numbers.slice[1]: 2.29343 != 2.29843]
49```
50
51The difference is in `Numbers.slice[1]`: the two values aren't equal using Go `==`.
52
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