snapshot

README

snapshot

Provides basic methods for snapshot testing, inspired by jest's snapshots

This package doesn't aim to be anything more than a simple utility to be used in conjunction with golang's own testing package, or any other testing framework which is also compatible with go test snapshots are auto-generated and managed by this package:

Getting started

1. Grab the package

go get -u github.com/vancelongwill/snapshot

1. Use it in tests

import (
  "testing"

  "github.com/VanceLongwill/snapshot"
)

type Something struct {
  MoreThings []string
}

func TestSomething(t *testing.T) {
  something := Something{}
  something.MoreThings = []string{"a", "b", "c"}
  label := "should be something"
  err := snapshot.WithLabel(label).Matches(&something)
  // returns an error with a pretty diff if the snapshot doesnt match
  if err != nil {
    // print the label and the diff
    t.Fatalf("Snapshot didn't match.\n - '%s'\n%s",
      label,
      err.Error())
  }
}

1. Update failing snapshots

go test ./... -u

Contributing

Contributions are absolutely welcome!

Steps

• Make sure tests are passing

  make test
  

• Make sure it passes the linter

  make test
  

• Open a pull request

Documentation

Overview

Package snapshot provides basic methods for snapshot testing Snapshot tests may be useful for regression testing or unit testing (with proper review) This package doesn't aim to be anything more than a simple utility to be used in conjunction with golang's own testing package, or any other testing framework which is also compatible with `go test` Snapshots are auto-generated and managed by this package:

Index

• Constants
• type Comparison
  • func WithLabel(label string) Comparison

Constants

const (
	// SnapshotDir is where snapshots are stored
	SnapshotDir string = "__snapshots__"
	// SnapshotExtension is the extension for snapshot files
	SnapshotExtension string = ".snap.xml"
	// Indent - 4 spaces
	Indent string = "    "
)

Types

type Comparison

type Comparison interface {
	// Matches runs a comparison with the saved snapshot
	// overwrites the saved snapshot if CLI flag "-u" is passed to `go test`
	Matches(v interface{}) error
}

Comparison compares snapshots

func WithLabel

func WithLabel(label string) Comparison

WithLabel reads the existing snapshot and allows comparison