BDD with Cucumber in IntelliJ

Setup Cucumber for BDD in IntelliJ.

Testing Life Cycle

As seen in this LinkedIn Learning course about Cucumber here

Define acceptance tests
Define features - cover as many scenarios (write BDD tests)
Write TDD unit tests

3 key components of Cucumber

Feature files

Feature, Scenario, Given/When/Then, in business domain language (using Gherkin).

Given a pre-condition
When an action is done
Then it produces a result

Example:

Feature: Reading an ebook
  Scenario: View Index Section
	Given: I am on any page of my ebook
	When: I access "Index" section
	Then: I should be navigated to the Index section

Step definition files.

In code, write Given/When/Then annotations with methods

Test runner

It glues feature with step definition files using JUnit.

Setup Cucumber in IntelliJ

As seen in the Jetbrains doc here

In IntelliJ Ultimate the plugins are enabled by default.

Settings/Plugins
Scroll down to see Gherkin, then Cucumber for Java

In IntelliJ Community, go to Settings/Preferences/Plugins/Marketplace, and search/install the following plugins in order:

Gherkin
Cucumber for Java

Setup JUnit in IntelliJ

Use Maven
Go to pom.xml, type Alt+Insert to add a dependency.
Add org.junit.jupiter:junit-jupiter.
Then reload the maven icon.

It should look like this, depending on the version:

<dependency>
	<groupId>org.junit.jupiter</groupId>
	<artifactId>junit-jupiter</artifactId>
	<version>5.9.0</version>
	<scope>test</scope>
</dependency>

Add the Cucumber library to Maven

Open pom.xml
Do Alt+Insert
Select Add Dependency
Search for Cucumber
Look for Cucumber-JVM: Java io.cucumber:cucumber-java
Click Add
Look for Cucumber-JVM: JUnit io.cucumber:cucumber-junit
Click Add

It should look like this, depending on the version:

<dependency>
	<groupId>io.cucumber</groupId>
	<artifactId>cucumber-java</artifactId>
	<version>7.10.1</version>
	<scope>test</scope>
</dependency>
<dependency>
	<groupId>io.cucumber</groupId>
	<artifactId>cucumber-junit</artifactId>
	<version>7.10.1</version>
	<scope>test</scope>
</dependency>

Reload Maven

Open the Maven tab (on the right). Click on the reload icon (first icon, hovering says Reload all Maven projects)

Prepare folder structure in `test` directory

In the test directory, there should be a green java directory, marked as Test Sources Root. If it’s not green then:

Right-click the test directory.
Select Mark Directory As
Then Test Sources Root

In the test directory, create the directory resources:

Right-click the test directory.
A popup shows the option to add a resources subdirectory already marked as Test Resources Root.
The icon is a directory with a small red/green diamond and a database-looking symbol.
If no popup is shown, then:
- After right-click test/
- Create a directory called resources
- Right-click this new directory
- Select Mark Directory As
- Then select Test Resources Root

Example Mapping

Clarify/Confirm the acceptance criteria using example mapping. As seen in the Cucumber blog here and this other website.

For example, a program that creates a list of numbers based on a filter criteria such as odd, even, or prime numbers.

Story: Create a list of odd numbers
- Rule: A list of positive integers should keep only odd numbers
	- Example: Input [0, 1, 2, 3, 4, 5] Output [1, 3, 5]
	- Example: Input [5, 5, 2, 0, 3, 1] Output [5, 5, 3, 1]

Story: Create a list of even numbers
- Rule: A list of positive integers should keep only even numbers
	- Example: Input [0, 1, 2, 3, 4, 5] Output [0, 2, 4]
	- Example: Input [5, 5, 2, 0, 3, 1] Output [2, 0]

Story: Create a list of prime numbers
- Rule: A list of positive integers should keep only prime numbers
	- Example: Input [0, 1, 2, 3, 4, 5] Output [2, 3, 5]
	- Example: Input [5, 5, 2, 0, 3, 1] Output [5, 5, 2, 3]

Create feature files

As seen in the Cucumber blog here. Don’t create a feature file for each user story. Instead, create feature files by functional areas, following a documentation hierarchy structure. For example:

features/
	customers/
		registration.feature
		login.feature
	payment/
		pay_on_delivery.feature
		pay_on_collection.feature
	api/
		customer_api.feature
		payment_api.feature

Inside the resources directory:

Create a directory features
Inside features create directories for functional areas.
Inside the functional area, create the FeatureName.feature files.
The .feature file has the cucumber icon.
Right-click/Run the .feature file to see Test Results

Example of a feature file

In the corresponding features package in the test/resources/ directory
Create a features file CreateNumbersList.feature
After adding the content, right-click this file to see the Test Results
It should produce an output recommending to add Given/When/Then methods