Wenbing Li

It's all about the fundamentals.

Cucumber Best Practices

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cucumber is a BDD(Behaviour driver development) framework. Basically test cases are written in plain text which is called Gherkin language, just in Given-When-Then steps. After that, developer will write implementation for those steps.

It’s good to bridge the communication between business requirement and implementation. The ideal work flow would be business analysis or QA write features and developer implements them. However, in a real world, developer write both of them. Cucumber is different programming model than what we normmaly use like Java, ruby, etc. It is not mature enough like OO which has tons of patterns and best practices to apply.

Below are some best practices when I use cucumber for one project.

Write declarative features

Scenarios should be written like a user would describe them.

Beware of scenarios that only describe clicking links and filling in form fields, or of steps that contain code or CSS selectors. This is just another variant of programming, but certainly not a feature description.

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Scenario: Adding a todo item
    Given I have a todo list named "Mondays list"
    When I go to the home page
    And I fill in "username" with "dave"
    And I fill in "password" with "secret"
    And I press "Log In"
    And I go to the todo page
    And I click on link "Mondays list"
    And I fill in "todo" with "Grab some milk"
    And I press "Add todo"
    Then I should see "Todo item added successfully"

Good

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Scenario: Adding a todo item
    Given I have a todo list
    And I am logged in as a normal user
    When I add a todo item
    Then It should be added to the todo list

Use As a <role>, I want <goal/desire> So that <benefit> format for feature description

Describe feature in user story style. Starts the feature and gives it a title, then follow with user story format.

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Feature: Create an account

  Scenario: ...

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Feature: Create an account
  As a user
  I want to create an account for me
  So that I can re-login to the same account

  Scenario: ...

Use should in each Then and following And steps

The purpose of Then steps is to observe outcomes and verify result. Using should word as a convention makes it easy to understand, and make sure do verification in implementation step.

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Then My job is displayed in the table

*Good

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Then My job should be displayed in the table

Capitalize first letter of every step

Each step is independant, capitalize first letter makes a nice format.

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Then my job should be displayed in the table

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Then My job should be displayed in the table

Use page object model

Don’t write implementation in step definition, use page object model.

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When(/^I search for my job$/) do
  visit path_to('manage jobs')
  find('a', :text => 'Filter Jobs').click
  fill_in('users-id-search', :with=>"")
  page.find('#users-id-search').native.send_keys(:backspace)
  fill_in('requisition.title', :with => @job.title)
  click_button('Search')
end

Good

job_steps.rb

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When(/^I search for my job$/) do
  @app.manage_job_page.load
  @app.manage_job_page.search @job.title
end

manage_job_page.rb

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def search(job_title)
  find('a', :text => 'Filter Jobs').click
  fill_in('users-id-search', :with=>"")
  page.find('#users-id-search').native.send_keys(:backspace)
  fill_in('requisition.title', :with => @job.title)
  click_button('Search')
end

Use background

If all the scenario in one feature file have the same steps, put them in the background.

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Scenario: Foo
  Given I am logged in as an admin
  And ....

Scenario: Bar
  Given I am logged in as an admin
  And ....

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Background:
  Given I am logged in as an admin

Scenario: Foo
  Given ....

Scenario: Bar
  Given ....

Use Tags

Tags are a great way to organise your features and scenarios.

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@job @smoke
Feature: Job management

Avoid to use step params

Step params is a smell which the feature is not declarative.

The parameter in feature should not be used as implementation parameter.

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Given I complete registration from using email "test@example.com"

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Given I complete registration form using a valid email

Avoid to use scenario outlines

A Scenario Outline provides a parametrized scenario script. However, it easily become an anti-pattern if you use it too many.

Each scenario with example actually means a different scenario. It’s better to use scenario with a meaningful name instead of using scenario example.

Scenario outlines uses step params, which should avoid to use.

Beware of feature that only has one scenario but have a long list of examples. It could be a smell that too many different scenario are put together.

Avoid to use data tables

Data tables provides data for implementation. It is against the rule of feature should be declarative and business focus.

Feature should not provide any detail implementation or data for testing.

Use Capybara find whenever possible

find will wait for a set amount of time and continuously retry finding the element until either the element is found or the time expires.

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first(".active").click

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find(".active", match: :first).click

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