Step Definitions - Cucumber Documentation (2024)

A Step Definition is a methodfunctionblockfunctionfunction with an expression that links it to one or more Gherkin steps.When Cucumber executes a Gherkin step in a scenario, it will look for a matching step definition to execute.

To illustrate how this works, look at the following Gherkin Scenario:

Scenario: Some cukes Given I have 48 cukes in my belly

The I have 48 cukes in my belly part of the step (the text following the Given keyword) will match the following step definition:

package com.example;import io.cucumber.java.en.Given;public class StepDefinitions { @Given("I have {int} cukes in my belly") public void i_have_n_cukes_in_my_belly(int cukes) { System.out.format("Cukes: %n\n", cukes); }}

package com.example;import io.cucumber.java8.En;public class StepDefinitions implements En { public StepDefinitions() { Given("I have {int} cukes in my belly", (Integer cukes) -> { System.out.format("Cukes: %n\n", cukes); }); }}

package com.exampleimport io.cucumber.java8.Enclass StepDefinitions : En { init { Given("I have {int} cukes in my belly") { cukes: Int -> println("Cukes: $cukes") } }}

package com.exampleimport io.cucumber.java8.Enclass StepDefinitions : En { init { Given("I have {int} cukes in my belly") { cukes: Int -> println("Cukes: $cukes") } }}

package com.exampleimport io.cucumber.scala.{ScalaDsl, EN}class StepDefinitions extends ScalaDsl with EN { Given("I have {int} cukes in my belly") { cukes: Int => println(s"Cukes: $cukes") }}

Given('I have {int} cukes in my belly') do |cukes| puts "Cukes: #{cukes}"end

const { Given } = require('cucumber')Given('I have {int} cukes in my belly', function (cukes) { console.log(`Cukes: ${cukes}`)});

A step definition’s expression can either be a Regular Expressionor a Cucumber Expression. The examples in this section use Cucumber Expressions.If you prefer to use Regular Expressions, each capture groupcapture groupcapture groupoutput parameteroutput parameter from the match will be passed as arguments to the stepdefinition’s methodfunctionblockfunctionfunction.

@Given("I have {int} cukes in my belly")public void i_have_n_cukes_in_my_belly(int cukes) {}

Given("I have {int} cukes in my belly") { cukes: Int -> println("Cukes: $cukes")}

Given("I have {int} cukes in my belly") { cukes: Int => println(s"Cukes: $cukes")}

Given(/I have {int} cukes in my belly/) do |cukes|end

Given(/I have {int} cukes in my belly/, function (cukes) {});

If the capture groupcapture groupcapture groupoutput parameteroutput parameter expression is identical to one of the registeredparameter types’s regexp,the captured string will be transformed before it is passed to thestep definition’s methodfunctionblockfunctionfunction. In the example above, the cukesargument will be an integer, because the built-in int parameter type’sregexp is \d+ .

A step definition can transfer state to a subsequent step definition by storingstate in instance variables.

let cukesState;Given('I have {int} cukes in my belly', cukes => { cukesState = cukes})

Step definitions aren’t linked to a particular feature file or scenario.The file, class or package name of a step definition does not affect what Gherkinsteps it will match. The only thing that matters is the step definition’sexpression.

When Cucumber encounters a Gherkin step without amatching step definition, it will print astep definition snippet with a matching Cucumber Expression.You can use this as a starting point for new step definitions.

Consider this Gherkin step:

Given I have 3 red balls

If you don’t have a matching step definition, Cucumber will suggest the followingsnippet:

@Given("I have {int} red balls")public void i_have_red_balls(int int1) {}

@Given("I have {int} red balls") { balls: Int ->}

Given("I have {int} red balls") { balls: Int =>}

Given('I have {int} red balls') do |int1|end

Given("I have {int} red balls", function (int1) {});

Suggested snippets will use your own parameter typesif they match parts of your undefined step. If a colorparameter type exists, Cucumber would use that in the suggested expression:

@Given("I have {int} {color} balls")public void i_have_color_balls(int int1, Color color) {}

@Given("I have {int} {color} balls") { balls: Int, color: Color ->}

}

Given("I have {int} {color} balls") { (balls: Int, color: Color) =>}

Given('I have {int} {color} balls') do |int1, color|end

Given("I have {int} {color} balls", function (int1, color) {});

Make sure you use the summary plugin when running Cucumber in orderto have the snippets printed.