bats-snapshot

bats-snapshot is a helper library providing snapshot assertions for Bats. This package is based on bats-assert

Dependencies:

• [bats-support][bats-support] (formerly bats-core) - output formatting
• [bats-assert][bats-assert] (formerly bats-core) - assertions

Install

In bats test

load '../node_modules/bats-support/load'
load '../node_modules/bats-assert/load'
load '../node_modules/bats-snapshot/load'

Usage

assert_snapshot

Fail if the output is not the same as snapshot

In first time calling, it will save the status and output into ./__snapshot__. In the second time, it will load the snapshot and try to match the current status and output

@test 'assert()' {
  run echo 'foo'
  assert_snapshot
}

On failure, the failed expression is displayed.

   -- output differs --
   expected : foo
   actual   : bar
   --

Partial matching

Partial matching can be enabled with the --partial option (-p for short). When used, the assertion fails if the expected substring is not found in $output.

@test 'assert_snapshot() partial matching' {
  run echo 'SUCCESS'
  assert_snapshot
  run echo 'ERROR: no such file or directory'
  assert_snapshot --partial
}

On failure, the substring and the output are displayed.

-- output does not contain substring --
substring : SUCCESS
output    : ERROR: no such file or directory
--

This option and regular expression matching (--regexp or -e) are mutually exclusive. An error is displayed when used simultaneously.

Regular expression matching

Regular expression matching can be enabled with the --regexp option (-e for short). When used, the assertion fails if the extended regular expression does not match $output.

Note: The anchors ^ and $ bind to the beginning and the end of the entire output (not individual lines), respectively.

@test 'assert_snapshot() regular expression matching' {
  run echo '^Foobar v[0-9]+\.[0-9]+\.[0-9]$'
  assert_snapshot
  run echo 'Foobar 0.1.0'
  assert_snapshot --regexp 
}

On failure, the regular expression and the output are displayed.

-- regular expression does not match output --
regexp : ^Foobar v[0-9]+\.[0-9]+\.[0-9]$
output : Foobar 0.1.0
--

An error is displayed if the specified extended regular expression is invalid.

This option and partial matching (--partial or -p) are mutually exclusive. An error is displayed when used simultaneously.