Jest-like snapshot testing in Golang

To install go-snaps, use go get:

go get github.com/gkampitakis/go-snaps

Import the go-snaps/snaps package into your code:

package example

import (
  "testing"

	"github.com/gkampitakis/go_snaps/snaps"
)

func TestExample(t *testing.T) {

  snaps.MatchSnapshot(t ,"Hello World")

}

You can pass multiple parameters to MatchSnapshot or call MatchSnapshot multiple times inside the same test. The difference is in the latter, it will create multiple entries in the snapshot file.

func TestSimple(t *testing.T) {

  t.Run("should make multiple entries in snapshot", func(t *testing.T) {
  
    snaps.MatchSnapshot(t, 5, 10, 20, 25)
    snaps.MatchSnapshot(t, "some value")
  
  })

}

By default go-snaps save the snapshots in __snapshots__ directory and the file name is the test file name with extension .snap.

So for example if your test is called add_test.go when you run your tests at the same directory a new folder will be created ./__snapshots__/add_test.snaps. You can change the extension or the directory name if you wish.

The example below will create a snapshot at ./mySnaps/<file-name>.txt.

func TestSimpleConfig(t *testing.T) {
	s := snaps.New(snaps.SnapsDirectory("mySnaps"), snaps.SnapsExtension("txt"))

	s.MatchSnapshot(t, 10)
}

Finally you can update your failing snapshots by setting UPDATE_SNAPS env variable to true.

UPDATE_SNAPS=true go test ....

You can also see some example usages in ./examples in this project.

Snapshots have the form

[ TestID ]
data
---

TestID is the test name plus an increasing number ( allowing to do multiple calls of MatchSnapshot inside a test ).

[TestSimple/should_make_a_map_snapshot - 1]
map[string]interface {}{
    "mock-0": "value",
    "mock-1": int(2),
    "mock-2": func() {...},
    "mock-3": float32(10.399999618530273),
}
---

Keep in mind the order in which tests are written might not be the same order that snapshots are saved in the file.

This library used Jest Snapshoting and Cupaloy as inspiration.

• Jest is a full-fledged Javascript testing framework and has robust snapshoting features.
• Cupaloy is a great and simple Golang snapshoting solution.

go test ./examples/... -v -count=1

MIT