What are snippets and how to they work

Snippets help reduce duplicate Steps within Features

What are Snippets

Snippets contain Gherkin steps that can be included within any feature with in the project.

Our original Gherkin Features are written with the file pattern <Feature>.hbs.feature and are contained in the "features/gherkin" directory.

The hbs identifies the file as a Handlebars template. When we run one of the composer commands having to do w/ Behat, we run this command composer behat-prep which actually then runs vendor/bin/preprocessGherkin.

What does preprocessGherkin with Snippets?

preprocessGherkin reads all the files in the features/gherkin directory looking for files w/ the pattern *.snippet.feature. It also reads all the *.hbs.feature files.

It then uses a PHP tool called LightnCandy. You can see it here: https://github.com/zordius/lightncandy. This project is a PHP implementation of Handlebars.

We treat our <Feature>.hbs.feature as our template, our handlebars template. The template is compiled and then our data is provided to the processed template.

Our <Feature>.hbs.feature might include a line like this,

{{{spinner}}}

As the example from our starter shows in inclusion of the {{{spinner}}}

Feature: Login to page 
  A login attempt with valid credentials
  Should be accepted
  A login attempt with bad credentials
  Should be rejected
    
  @javascript @snapshot
  Scenario: Login with bad credentials
{{>loginForm name="badusername@crossbrowsertesting.com" password="badpassword"}}
{{{spinner}}}
    Then the "Username or password is incorrect" element exists
    And I take a snapshot called 'failed_login'

and our spinner.snippet.feature look like this:

    And I wait for the "Verifying credentials" spinner

Notice how the gherkin uses the spinner name and the snippet.feature is named the same, namely spinner.

Now, within any Gherkin hbs template, we can use the spinner snippet.

Note that a snippet can be any length necessary.

Once the preprocessGherkin finishes, we should see our fully realized Gherkin in the features/temp directory. Continuing w/ our example, this would be our features/temp/*.feature:

Feature: Login to page 
  A login attempt with valid credentials
  Should be accepted
  A login attempt with bad credentials
  Should be rejected
    
  @javascript @snapshot
  Scenario: Login with bad credentials

    Given I go to the "Login form" page
    And I fill the "username" with "badusername@crossbrowsertesting.com"
    And I fill the "password" with "badpassword"
    And I click the "submit" button
    And I wait for the "Verifying credentials" spinner