Test::BDD::Cucumber::Manual::Steps - How to write Step Definitions


version 0.12


The 'code' part of a Cucumber test-suite are the Step Definition files which match steps, and execute code based on them. This document aims to give you a quick overview of those.


Most of your step files will want to start something like:


 use strict;
 use warnings;

 use Test::More;
 use Test::BDD::Cucumber::StepFile;
 use Method::Signatures;

The fake shebang line gives some hints to syntax highlighters, and use strict; and use warnings; are hopefully fairly standard at this point.

Most of my Step Definition files make use of Test::More, but you can use any Test::Builder based testing module. Your step will pass its pass or fail status back to its harness via Test::Builder - each step is run as if it were its own tiny test file, with its own localized Test::Builder object.

Test::BDD::Cucumber::StepFile gives us the functions Given(), When(), Then() and Step(). These pass the step definitions to the class loading the step definitions, and specify which Step Verb should be used - Step() matches any.

Method::Signatures allows us to use a small amount of syntactic sugar for the step definitions, and gives us the func() keyword you'll see in a minute.


 Given qr/I have (\d+)/, func ($c) {
    $c->stash->{'scenario'}->{'count'} += $1;

 When "The count is an integer", func ($c) {
    $c->stash->{'scenario'}->{'count'} =
        int( $c->stash->{'scenario'}->{'count'} );

 Then qr/The count should be (\d+)/, func ($c) {
    is( $c->stash->{'scenario'}->{'count'}, $c->matches->[0], "Count matches" );

Each of the exported verb functions accept a regular expression (or a string that's used as one), and a coderef. The coderef is passed a single argument, the Test::BDD::Cucumber::StepContext object. To make this a little prettier, we use Method::Signatures's func() keyword so we're not continually typing: sub { my $c = shift; ... .

We will evaluate the regex immediately before we execute the coderef, so you can use $1, $2, $etc, although these are also available via the StepContext.


How step files are loaded is discussed in Test::BDD::Cucumber::Manual::Architecture, but isn't of much interest. Of far more interest should be seeing what you have available in Test::BDD::Cucumber::StepContext...


Peter Sergeant


Copyright 2011, Peter Sergeant; Licensed under the same terms as Perl