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Peter Sergeant

NAME

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

VERSION

version 0.26

INTRODUCTION

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.

STARTING OFF

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

 #!perl

 use strict;
 use warnings;

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

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.

STEP DEFINITIONS

 Given qr/I have (\d+)/, sub {
    S->{'count'} += $1;
 }

 When "The count is an integer", sub {
    S->{'count'} =
        int( S->{'count'} );
 }

 Then qr/The count should be (\d+)/, sub {
    is( S->{'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. Before the subref is executed, localized definitions of S and C are set, such that the lines below are equivalent:

  # Access the first match
  sub { my $context = shift; print $context->matches->[0] }
  sub { C->matches->[0] }

  # Set a value in the scenario-level stash
  sub { my $context = shift; my $stash = $context->stash; $stash->{'count'} = 1 }
  sub { S->{'count'} = 1 }

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.

NEXT STEPS

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...

AUTHOR

Peter Sergeant pete@clueball.com

LICENSE

Copyright 2011-2014, Peter Sergeant; Licensed under the same terms as Perl




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