Specifying constants in Cucumber Transforms

Usually a cucumber step definition will have some sort of regular expression capture:

Given(/^I have (\d+) dollars in my account$/) do |amount|
  #step logic
end

As the Given is specified above the amount argument will still be a string. A Transform method can convert that to a number (instead of doing the conversion directly in the step definition itself:

Transform(/^\d+$/) do |number|
  number.to_i
end

Cucumber also supports an even more awesome capability: The ability to name transforms and use them in step captures:

CAPTURE_CASH_AMOUNT = Transform(/^\d+$/) do |digits|
  digits.to_i
end

#And the step definition looks like:
Given(/^I have \$(#{CAPTURE_CASH_AMOUNT}) dollars in my account/) do |amount|
  #step logic
end

This makes the meaning of the capture group very obvious and it also allows for refactoring of the regular expression to be a little simpler since it's done in one place: The transform method. For example if we wanted to include currency symbols:

CAPTURE_CASH_AMOUNT = Transform(/^(\$|€)(\d+)$) do |currency_symbol, digits|
end

Chris

Say thanks

Last edit

2018-01-09

Chris

How does Cucumber find supporting code?

The directories scanned for steps are determined by the feature file(s)/directories passed to the cucumber command. Cucumber will look in the sub-directories of the feature files

features
  billing
    credit_card.feature
  scoring
    multi_...

Cleaning up feature branches in git

After working on a feature in a separate branch, keeping the branch around is unnecessary. To clean up afterwards, run the following:

git push origin --delete <branch_to_delete>
git branch -D <branch_to_delete>

Posted by Chris to Chris's deck (2018-01-09 14:44)

Specifying constants in Cucumber Transforms

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