Gherkin

Gherkin is the language that Cucumber understands.
It is a Business Readable, Domain Specific Language
that lets you describe software’s behaviour without detailing how that behaviour is implemented.
Gherkin serves two purposes – documentation and automated tests.
-And a third bonus feature – when it yells in red don’t be offended – it’s talking to you, telling you what code you should write.

Gherkin’s grammar is defined in the Treetop grammar that is part of the Cucumber codebase.
The grammar exists in different flavours for several Spoken languages,
so that your team can use the Given-When-Then keywords (plus a few more) in your own language.

Syntax Notes

The following notes are an unofficial (and possibly inaccurate) summary of Gherkin syntax. YMMV…

General

Comment Lines

Comment lines are allowed anywhere in the file.
They begin with zero or more spaces, followed by a sharp sign (#).

Headings and Verbs

Each non-comment line in Gherkin begins with a “heading” (eg, Feature:)
or an “action” (eg, Given).
The following text is either unparsed or parsed by regular expressions in a “steps” file.
The heading/action is separated from the following text by one or more spaces,
which are not passsed to the regular expressions.

Gherkin provides parsers for dozens of languages, including (at this writing)
Arabic, Chinese (Simplified), Danish, Dutch, English, Estonian, French, German, Italian, Japanese,
Korean, Lithuanian, LOLCAT, Malay, Norwegian, Polish, Portuguese,
Romanian (with and without diacritical marks), Russian,
Spanish, Swedish, Texan, and Welsh.
This note lists only the English reserved words;
for corresponding words in other languages, see …/lib/cucumber/languages.yml.

  and:               And
  but:               But
  examples:          Examples
  feature:           Feature
  given:             Given
  given_scenario:    GivenScenario
  more_examples:     More Examples
  scenario:          Scenario
  scenario_outline:  Scenario Outline
  then:              Then
  when:              When