Unless you are used to Cucumber nomenclature, you may be wondering about the terms that surround Lettuce concepts.
If this is your case, this introduction will guide you through the very basic keywords that concept Lettuce.
Since Lettuce is based on the behaviour of the project that is being designed, you will think on features.
After enumerating features, you will create scenarios to describe its feature. Thus, scenarios are components of a feature.
Let’s learn by example, supposing we want to create a system to manage a contact book.
OK, one of the very basic feature of a contact book is adding names and phones of a person.
See how this feature could be described with Lettuce above:
Feature: Add people to contact book
In order to organize phones of friends
As a wise person
I want to add a people to my contact book
Scenario: Add a person with name and phone
Given I fill the field "name" with "John"
And fill the field "phone" with "2233-4455"
When I save the data
Then I see that my contact book has the persons:
| name | phone |
| John | 2233-4455 |
Scenario: Avoiding a invalid phone number
Given I fill the field "name" with "John"
And fill the field "phone" with "000"
When I save the data
Then I get the error: "000 is a invalid phone number"
In the feature above we can notice a few elements, for instance:
- The feature name:
Feature: Add people to contact book
- Feature headline:
In order to organize phones of friends As a wise person I want to add a people to my contact book
- Scenarios:
Scenario: Add a person with name and phone Given I fill the field "name" with "John" And fill the field "phone" with "2233-4455" When I save the data Then I see that my contact book has the persons: | name | phone | | John | 2233-4455 | Scenario: Avoiding a invalid phone number Given I fill the field "name" with "John" And fill the field "phone" with "000" When I save the data Then I get the error: "000 is a invalid phone number"
One or more scenarios compose a feature. And there are two kinds of scenarios:
The simple scenarios are composed by steps, no matter if they are simple or tabulated steps.
The feature above is composed by two simple scenarios.
Outlined scenarios are very handy and avoid repetition.
Supposing that we need fill the same formulary many times, each time with a different data set.
Let’s see how it could be done with scenario outlines:
Feature: Apply all my friends to attend a conference
In order to apply all my friends to the next PyCon_
As a lazy person
I want to fill the same form many times
Scenario Outline: Apply my friends
Go to the conference website
Access the link "I will attend"
Fill the field "name" with "<friend_name>"
Fill the field "email" with "<friend_email>"
Fill the field "birthday" with "<friend_birthdate>"
Click on "confirm attendance" button
Examples:
| friend_name | friend_email | friend_birthdate |
| Mary | mary@domain.com | 1988/02/10 |
| Lincoln | lincoln@provider.net | 1987/09/10 |
| Marcus | marcus@other.org | 1990/10/05 |
In a nutshell, the scenario above is equivalent to write this amount of text:
Feature: Apply all my friends to attend a conference
In order to apply all my friends to the next PyCon_
As a lazy person
I want to fill the same form many times
Scenario: Apply Mary
Go to the conference website
Access the link "I will attend"
Fill the field "name" with "Mary"
Fill the field "email" with "mary@domain.com"
Fill the field "birthday" with "1988/02/10"
Click on "confirm attendance" button
Scenario: Apply Lincoln
Go to the conference website
Access the link "I will attend"
Fill the field "name" with "Lincoln"
Fill the field "email" with "lincoln@provider.net"
Fill the field "birthday" with "1987/09/10"
Click on "confirm attendance" button
Scenario: Apply Marcus
Go to the conference website
Access the link "I will attend"
Fill the field "name" with "Marcus"
Fill the field "email" with "marcus@other.org"
Fill the field "birthday" with "1990/10/05"
Click on "confirm attendance" button
As you can notice, scenario outlines are really useful and help you to avoid repetition of text and code.
Comparable with Scenarios, Steps comes in two kinds:
Simple steps are actually simple, they are matched with step definitions.
Lettuce considers each line of a scenario as a simple step, the only exception is if the first non-blank character of the line is a pipe |, in this case Lettuce will consider the step as a tabular step.
In a nutshell, a simple step may look like this:
Given I go to the conference website
Analog to Outlined Scenarios, the tabular steps are very useful, and avoid repetition of text.
Tabular steps are specially useful to set up some data set in aa scenario, or compare a set of data to results at the end of the scenario.
But nothing avoid you to use at your will.
Example:
Given I have the following contacts in my database
| name | phone |
| John | 2233-4455 |
| Smith | 9988-7766 |
May 25, 2010