Test automation with Cucumber-JVM

Boston Java Meetup, 13/06/2013
Test Automation
with Cucumber-JVM
Alan Parkinson
@alan_parkinson

Cucumber is a tool that executes plain-text
functional descriptions as automated tests
• Tests written in business-facing text
 Supports over 40 spoken languages
 This test is called Gherkin
• Automation written in target language
 Ruby, Java, Scala, Groovy, etc.. .net, python, PHP

• Program does not do what it is intended
• Fixed in development/QA
• Program does what is intended
• Unstated, misunderstood or tacit
requirements
IMPLEMENTATION DEFECT
REQUIREMENTS DEFECT
Software - What can go wrong?

A woman asks her husband, a
programmer, to go shopping.
She tells him “please, go to the nearby
grocery store to buy some bread. Also, if
they have eggs, buy 6”

50-60%of issues identified by testers can be chalked down as
Requirements Defects
100-200%more expensive to fix than other defects because
the code is already written

How does BDD help?
• All stakeholders involved in the discussion drives out clear and concise
specifications centred around business value.
• Write specifications in natural language so everyone is on the same page
• Turn the specification into acceptance tests that guarantees the software does
as it is intended
• Use those tests as the software evolves to guarantee that it continues to work
as intended.
• Specifications are documentation – each scenario describes how the system is
being used

Cucumber, The Origins
• Cucumber
 Ruby
 Born 2007-2008
• Cuke4Duke
 First seen in 2008
 JRuby
• Cucumber-JVM
 Released April 2012
 Java, Groovy, Clojure, Scala, Ioke, Jython, Rhino (JavaScript) and JRuby

Maven Dependencies
cucumber-
java
cucumber-
junit
cucumber-
picocontainer
cucumber-
guice
cucumber-
spring

Maven Dependencies
<dependency>
<groupId>info.cukes</groupId>
<artifactId>cucumber-picocontainer</artifactId>
<version>${cucumber.version}</version>
</dependency>
<dependency>
<groupId>info.cukes</groupId>
<artifactId>cucumber-junit</artifactId>
<version>${cucumber.version}</version>
</dependency>

Scenarios - Given When Then
Given an owner with a registered pet called “Sly“
When the owner registers a new pet called “Sly“
Then the user should be warned that the pet already
exists

Writing Scenario's in Cucumber
• Scenarios are organized together into features
• Each feature is represented as a plain text file.
• Feature files must have the “.feature” extension
• Each feature can contain many scenarios

JUnit Runner
import org.junit.runner.RunWith;
import cucumber.junit.Cucumber;
@RunWith(Cucumber.class)
public class RunnerIT {
}

JUnit Runner 2
• Body of the class should be empty
 No @Test annotated methods
 No @Before or @After methods
• Arguments can be provided with an additional
annotation

JUnit Runner - Arguments
@RunWith(Cucumber.class)
@Cucumber.Options(
features = "src/test/resources/features“
)
public class RunnerIT {
}

Step Definitions
• A single Method representing a Step from a Feature file
• The Method is annotated with information about the step it
represents
• Cucumber generates “Code Snippet's” for Step Definition it
can’t find

Step Annotations
import cucumber.annotation.en.*;
Each Gherkin step keyword has a Annotation
@When("^we want to stop traffic$")
public void methodName() { … }

Passing and Failing
• Each step has it own result state
 Passed
 Pending
 Skipped
 Failed
• Individual step result state combined determine the
Scenarios success or failure
• Steps can be failed on exceptions or JUnit Assertion failures

Regex Lesson
Cucumber uses Regular Expressions to match steps to
definitions.
@When("^we want to stop traffic$")
^ Matches the starting position
$ Matches the ending position

Capturing Arguments
@Given("^an owner with a pet called "Sly"$")
public void an_owner_with_a_pet_called() {
…
}
@Given("^an owner with a pet called "([^"]*)"$")
public void an_owner_with_a_pet_called(String name) {
…
}

Capturing Arguments 2
• The pair of brackets is a capture group
• Everything captured is passed to method parameter
• Cucumber will automatically convert to the method
parameter type
• Equal number of method parameters and capture groups

Type Conversion
• If the captured string is not in the correct format for type
conversion an error will be thrown
• Use regular expressions to capture the correct format string
for the type
Note: Escape regular expression characters with backslash

Typical Capture Groups
(.+) Good for capturing strings and dates
"([^"]*)" Captures a string within Double quotes
(d) Capture decimal numbers only
(d+.d+) Capture floating point numbers
(true|false) Captures a Boolean value

Date Formats
@Given ("^today is (.+)$")
public void today_is(Date date) {
….
}
Dates are recognized if it’s a format from the DateFormat class

Date Formats
SHORT is completely numeric, such as 12.13.52 or 3:30pm
MEDIUM is longer, such as Jan 12, 1952
LONG is longer, such as January 12, 1952 or 3:30:32pm
FULL is pretty completely specified, such as Tuesday, April 12,
1952 AD or 3:30:42pm PST.

Date Formats
import cucumber.DateFormat;
@Given ("^today is (.+)$")
public void today_is(
@DateFormat ("yyyy-MM-dd") Date date) {
….
}

Tag use cases
• Grouping Scenarios together
 Identify slow running test that shouldn’t be run frequently
 Identify tests that require a particular library or server

Running Scenarios with a Tag
@Cucumber.Options(
tags = {“@WebDriver”}, … )

Running Scenarios without a Tag
Cucumber can exclude Scenarios with a particular tag by
inserting the tilde character before the tag
For the following command will run all Scenarios without the
WebDriver tag
@Cucumber.Options(
tags = {“~@WebDriver”}, … )

Tag expressions – Logical OR
Separate a list of tags by commas for a Logical OR tag
expression
@Cucumber.Options(
tags = {“@WebDriver,@email”}, … )

Tag expressions – Logical AND
Specifying multiple tag arguments creates a logical AND
between each tag expression.
@Cucumber.Options(
tags = {“@WebDriver”, ”@email”}, … )

Tag expressions – AND OR
Run scenarios that are tagged with @WebDriver or @email
but not @slow
@Cucumber.Options(
tags = {“@WebDriver,@email”, “~@slow”}, … )

Further information
Official website: cukes.info
Github: github.com/cucumber/cucumber-jvm
Hindsight Software: hindsighttesting.com

Thank you
Alan Parkinson
CEO and Co-founder, Hindsight Software Ltd
alan.parkinson@hindsightsoftware.co.uk
@alan_parkinson

Test automation with Cucumber-JVM

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