Writing scenarios with Gherkin syntax
CucumberStudio enables you to create executable specifications written in a language called Gherkin.
Gherkin is a plain-text language with a little extra structure. Gherkin is designed to be easy to learn by non-programmers, yet structured enough to allow concise description of examples to illustrate business rules in most real-world domains.
Here is a sample Gherkin document:
Scenario: Account has sufficient funds
Given the account balance is $100
And the card is valid
And the machine contains enough money
When the Account Holder requests $20
Then the ATM should dispense $20
And the account balance should be $80
And the card should be returned
The main keywords in Gherkin are:
- Feature
- Scenario
- Given, When, Then, And, But (Steps)
- Background
- Scenario outline
- Examples
Step 1: Activate the BDD mode
In your project settings panel, activate the BDD mode.
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This will enable you to write scenarios using the Gherkin syntax. The step editor in the scenario page will create only action words (reusable steps) and interpret the Gherkin keywords.
Step 2: Create a feature
Your features are managed with folders to better organize your project.
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A feature has a description that provides the context. It is usually written this way:
I want [feature]
So that [benefit]
A feature contains one or many scenarios that describe its behaviors.
Step 3: Write a scenario with the Given/When/Then syntax
By getting the business users, the analysts, the testers and the developers to adopt this vocabulary of “given/when/then”, lots of ambiguities fall away and conversations become more efficient.
Let’s write our first step: given the account balance is “$100”
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CucumberStudio interprets and highlights the keyword Given. It will also consider $100 as a parameter because of the double quotes “my parameter value“. This way you’ll be able to reuse the same step in the future with a different value.
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And after a couple of seconds we get the following scenario.
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| Note: | The step editor comes along with a powerful suggestion capability that enables you to reuse existing steps and design scenarios with a consistent business terminology. It’s also possible to use free text parameters in steps. |
Step 4: add examples and use scenario outline
Cloning scenarios to use different values can quickly become tedious and repetitive. Scenario outlines allow you to more concisely express these examples through the use of parameters and datatable. Using our previous scenario we can create 3 examples.
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When you create a new step, you can directly use the column name between “…” to use it as a parameter:
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After the step validation, you can notice that the character = is automatically set before the column name. This indicates that the word after the = character is a variable that will be replaced by the matching datatable column value.
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You can also write an expression as a parameter value. This expression can use the datatable column names. For example, here, the parameter value is the addition of the value of the column x and the column y:
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After clicking on View tests, you get a preview of your generated tests:
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Now that we have the scenarios completed. Let’s execute them.