rspec-inline-snapshot

Inline snapshot matchers for RSpec. Inspired by Jest, rspec-snapshot, and others!

Open-sourced in 2022 by Hummingbird RegTech, Inc.

Add this line to your application's Gemfile:

gem 'rspec-inline-snapshot'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install rspec-inline-snapshot

The gem provides the match_inline_snapshot RSpec matcher. This matcher will self-modify the spec file with the expected value.

If the matcher is not provided with an argument, the code will update the snapshot by editing the spec file on first run. This can also be a useful workflow for updating a single snapshot... simply remove the argument and re-run the test.

expect(what_the_cat_said).to match_inline_snapshot

# ... will result in the code self-modifying ... and the test passes

expect(what_the_cat_said).to match_inline_snapshot('meow')

If an expected value is passed to the matcher, the behavior depends on whether the UPDATE_SNAPSHOTS environment variable is set. If it is set, the snapshot is updated (surprise!). If it is not, the test will fail.

# ... without UPDATE_SNAPSHOTS=true set ... 
expect(what_the_cat_said).to match_inline_snapshot('woof') # boom!

# ... with UPDATE_SNAPSHOTS=true set ...
expect(what_the_cat_said).to match_inline_snapshot('woof')
# ... will result in the code self-modifying ... and the test passes
expect(what_the_cat_said).to match_inline_snapshot('meow')

The snapshotting works with many kinds of objects. In the event of a multi-line string, it will generate a heredoc to enhance readability.

expect(JSON.pretty_generate(some_hash)).to match_inline_snapshot(<<~SNAP.chomp)
  {
    "a": 1,
    "b": 2,
    "c": {
      "d": 3,
      "e": 4
    }
  }
SNAP

expect(number_of_cats).to match_inline_snapshot(123)

expect(what_the_cat_said).to match_inline_snapshot('meow')

For legacy reasons, the UPDATE_MATCH_SNAPSHOT and UPDATE_SNAPSHOTS environment variables are equivalent and can be used interchangeably.

Most CI providers set the CI environment variable. rspec-inline-snapshot will detect this and "do the right thing" in this situation... it will refuse to update snapshots.

Just send a bug report or pull request on Github!

Our lawyers would like you to know that if you do send a pull request, you are agreeing to license your code under the same license as the rest of the repo, the Apache 2.0 license.