Feature: Strict keywords matching

[vitalets]

The problem
Currently, keywords Given, When, Then are just aliases for the same function. The keyword is not taken into account when searching for step definition by step text. Some users would like to enable strict matching and avoid ambiguity in feature files.

A solution
Provide an option to enable strict keywords matching. When enabled, the following code will throw an error.
Step definition:

Given(“I have {number} dollars”, () => { ... })

Feature:

  Scenario: a scenario
    Given I have 100 dollars
    When I win in a lottery
    Then I have 200 dollars   # <- will throw an error, b/c step is defined with Given

There were several discussions in Cucumber community. In general, many people voted for such option.

• Implement unambiguous keywords cucumber/cucumber-js#2043
• Proposal: Unambiguous Keywords cucumber/common#768
• Keywords : Strict keyword enforcement  cucumber/common#1392

Rules applied in strict mode

1. step text started with Given, When, Then matches only definitions with the corresponding keyword or with universal Step function
2. step text started with And / But looks up the nearest full keyword (Given, When, Then) and then follows the rule 1
   • if the first step starts with And / But, it is treated as Given
3. step text started with * matches definitions with any keyword

Option name

• respectKeywordDefinition: true
• strictKeywords: true
• matchKeywords: true
• keywordsMatch: true