Gherkin is a Business Readable language that Cucumber understands and describes the application flow. In cucumber each line should start with a Gherkin keyword. Gherkin provides the following keywords:

Feature

Scenario

Scenario Outline

Examples

Background

Given

When

Then

And

Feature: Each feature file should start with "Feature" keyword. This keyword basically defines the business logic that we are testing. Let suppose we have to test the login feature then there will be one feature file for the login functionality and this feature file may contain different scenarios in which we will test the login functionality for valid user, login functionality for invalid user and so on.

Scenario: Scenario basically defines a business rule. As per the above defined feature, there will be different scenarios like Validate login error messages, validate login functionality for valid user, validate login functionality for invalid user, etc..

Scenario Outline: We use Scenario Outline in place of Scenario when there is need to parameterize the testcase or any complex business logic. Suppose we have to test the login functionality for 3 users then there we have to write 3 different scenarios and 3 different step definitions too.

Feature: Verify the Signin Functionality

 Scenario: Signin for User1

    Given I am at Home Page

    And I clicked on SignIn link

    And I enter “User1” as username

    And I enter “User1” as password

    And I clicked on SignIn button

    Then I should see the Activities page

 Scenario: Signin for User2

    Given I am at Home Page

    And I clicked on SignIn link

    And I enter “User2” as username

    And I enter “User2” as password

    And I clicked on SignIn button

    Then I should see the Activities page

 Scenario: Signin for User3

    Given I am at Home Page

    And I clicked on SignIn link

    And I enter “User3” as username

    And I enter “User3” as password

    And I clicked on SignIn button

    Then I should see the Activities page

Since the business logic is same and only the username and password is changing, so we will use Scenario Outline instead of Scenario and pass the value in the Examples section.

 Scenario Outline: Signin for Users

    Given I am at Home Page

    And I clicked on SignIn link

    And I enter <Username> as username

    And I enter <Password> as password

    And I clicked on SignIn button

    Then I should see the Activities page

    Examples:

     | Username | Password |

     | User1        | User1       |

     | User2        | User2       |

     | User3        | User3       |

Examples: Examples is basically a section that contains the data table. The first row in the table must contain a header corresponding to the variables used in the Scenario Outline steps. Examples section is a mandatory part for Scenario Outline ie whenever we are using Scenario Outline in our feature file then we have to use Examples section in the last. Refer the above example.

Background: In the Scenario Outline example we have seen that we have given the pre-condition(given after ‘Given’ keyword) three times. Since this step is repeated in every scenario, so we can use Background keyword and put the “Given” keyword step inside Background. Now, we do not have give the pre-condition step with each scenario. Step mentioned in the Background section gets executed before every scenario.

Background:

    Given I am at Home Page

Given: This keyword is used to define the pre-condition of any scenario. When cucumber executes the Given logic then it is basically creating a platform for the next step to execute.

When: When steps are used to describe an action that user will perform. We should use only single When step for each scenario.

Then: Then steps are used for the assertion purpose. In When steps we have triggered an action, so some output or result is displayed. Now we verify that result in Then step.

And: And steps are basically used to concatenate Given, When, Then steps.