BDD - Quick Start Guide

Behavior-driven development (BDD) is a software development methodology in which an application is specified and designed by describing how its behavior should appear to an outside observer. 

Principles of BDD: -

• First define a test set for the unit/module
• Make the test fail
• Then implement the failed unit
• Finally verify that the implementation of the unit makes the tests success

Concepts to Remember: -

• Keywords:
• Feature: List of scenarios.
• Scenario: Business rule through list of steps with arguments.
• Given: Some precondition step
• When: Some key actions
• Then: To observe outcomes or validation
• And, But: To enumerate more Given, When, Then steps. But is mainly used for negative scenarios
• Scenario Outline: List of steps for data-driven as an Examples and <placeholder>
• Examples: Container for s table
• Background: List of steps run before each of the scenarios

• Symbols:
• """ (Doc Strings)
• | (Data Tables)
• @ (Tags/Labels): To group Scenarios 
• <> (placeholder)
• "" (scenario parameter container)
• # (Comments)

• Feature File Definition Template: -

        @tag

          Feature: Title of your feature

                  I want to use this template for my feature file

          @tag1

          Scenario: Title of your scenario

          Given I want to write a step with precondition

             And some other precondition

          When I complete action

             And some other action

             And yet another action

          Then I validate the outcomes

          And check more outcomes

         @tag2

          Scenario Outline: Title of your scenario outline

          Given I want to write a step with <name>

          When I check for the <value> in step

          Then I verify the <status> in step

          Examples:

          | name    |value | status |

          | name1  |  5       | success|

          | name2    7   | Fail   |

• Step Definition: -  When Cucumber executes a Step in a Scenario it will look for a matching Step Definition to execute. A Step Definition is a small piece of code with a pattern attached to it. The pattern is used to link the step definition to all the matching Steps, and the code is what Cucumber will execute when it sees a Gherkin Step.
• Example: - Using Java & Cucumber

• Runner File: - Mainly it's the driver to drive whole test execution.
• Options: -
• -g, --glue PATH -Where glue code (step definitions and hooks) is loaded from.
• -f, --format FORMAT[:PATH_OR_URL]  How to format results. Goes to STDOUT unless PATH_OR_URL is specified. Built-in FORMAT types: junit, html, pretty, progress, json. FORMAT can also be a fully qualified class name.
• -t, --tags TAG_EXPRESSION - Only run scenarios tagged with tags matching TAG_EXPRESSION.
• -n, --name REGEXP - Only run scenarios whose names match REGEXP.
•  -d, --[no-]-dry-run - Skip execution of glue code.
• -m, --[no-]-monochrome - Don't colour terminal output.
• -s, --[no-]-strict - Treat undefined and pending steps as errors.
• --dotcucumber PATH_OR_URL-Where to write out runtime information. PATH_OR_URL can be a file system path or a URL
• -v, --version - Print version.
• -h, --help - You're looking at 
• Example: - Using Java & Cucumber

Market Leading Tools: -

• Cucumber: - https://cucumber.io/
• JBehave: - http://jbehave.org/
• SpecFlow:- http://specflow.org/
• Serenity: - http://www.thucydides.info/#/
• Spinach: - http://www.rubydoc.info/github/codegram/spinach/master