In the world of automation testing, generating realistic-looking test data is a preferred approach to using static fixtures.

FakerMaker is a Ruby gem that allows you to do just that; using factories to create the test data you need. It can be used with Faker to dynamically generate test data.

Initialisation

We can use Faker and FakerMaker to create a factory for an API request body like this:

require 'faker'
require 'faker_maker'

FakerMaker.factory :example_request, naming: :json do
  name { Faker::Name.name }
  building_number { Faker::Address.building_number }
  street_name { Faker::Address.street_name }
  city { Faker::Address.city }
  country { Faker::Address.country }
end

Which can be called to create a request body like this:

body = FM[:example_request].build.as_json
=> {"name"=>"The Hon. Earleen Wunsch",
    "buildingNumber"=>"148",
    "streetName"=>"Mueller Lodge",
    "city"=>"Port Darin",
    "country"=>"Canada"}

Often when testing we need to use specific values in the test data, however.

An example: we need to send a API request with “city” set to “London” and “country” set to “United Kingdom”.

Inefficient overwriting

This can be done in 4 steps by:

  1. Initialising a template request:

    body = FM[:example_request].build.as_json
=> {"name"=>"Eleni Daniel",
    "buildingNumber"=>"50962",
    "streetName"=>"Jacqulyn Lights",
    "city"=>"New Rubin",
    "country"=>"Isle of Man"}

  2. Overwriting the value of “city” in the request:

    body["city"] = "London"

  3. Overwriting the value of “country” in the request:

    body["country"] = "United Kingom"

  4. Sending a request containing the overwritten body:

    body
=> {"name"=>"Eleni Daniel",
  "buildingNumber"=>"50962",
  "streetName"=>"Jacqulyn Lights",
  "city"=>"London",
  "country"=>"United Kingdom"}

Though this works, it can be considered “more expensive” than needed, as today I learned from a colleague a simple trick to do this more efficiently in just 2 steps…

Efficient initialising

  1. Initialising the request with the values we need for the relevant parameter:

    body =
  FM[:example_request].build(city: "London", country: "United Kingdom").as_json

  2. Sending a request containing the efficiently initialised body:

    body
=> {"name"=>"Msgr. Ernesto Reynolds",
"buildingNumber"=>"942",
"streetName"=>"Goyette Passage",
"city"=>"London",
"country"=>"United Kingdom"}

Job done. Initialising our test data was done more efficiently in a single line of code.

In the context of large automation test packs dealing with complex data, this simple trick can be particularly beneficial to improving efficiency.