StubFactory

A blunt StubFactory that helps to test tightly coupled code, but handle with care: This is not a best practice. If you find yourself relying on this a lot, you might have to rethink your design.

Installation

Add this line to your application's Gemfile:

gem 'blunt_stub_factory', require: 'stub_factory'

And then execute:

$ bundle

Or install it yourself as:

$ gem install blunt_stub_factory

Usage

require 'stub_factory'
# beware: StubFactory resides in the stub_factory file, not as it's gemname would indicate (the name stub_factory was already taken...)

Class A
  attr_reader :test, :test2

  def initialize
    @test  = "a value"
    @test2 = "another value"
  end

  def a_method
    "original return"
  end
end

StubFactory provides a method to bypass the constructor of an object and set it's instance variables by force.

a = A.new_stub(vars: { test: "overwritten" })
b = A.new

a.test 
# => "overwritten"
b.test 
# => "original value"

Default as well as custom templates to overwrite variables can be defined - StubFactory automatically looks for such statements in your spec/factories folder. Only files named template_***.rb are loaded.

StubFactory.define_template(:a) do
  { test2 = "template value" }
end

StubFactory.define_template(:other) do
  { test2 = "custom value" }
end

# a new stub tries to look up a template by his class name by default
a = A.new_stub
a.test2
# => "template value"

# default template overwritten with custom template
b = A.new_stub(template: :custom)
b.test2
# => "custom value"

# if template is passed with a value of nil, no template will be used
c = A.new_stub(template: nil)
c.test2
# => "another value"

Method return values can be stubbed.

a = A.new_stub(methods: { a_method: "overwritten method" }
b = A.new

a.a_method
# => "overwritten method"
b.a_method
# => "original return"

For ease of use, helper methods can be defined when they are included in your RSpec configuarion. Place define_helper statements in your spec/support/helpers folder. Only files named stub_***.rb are loaded.

RSpec.configure do |config|
  config.include StubFactory::Helpers
end

StubFactory.define_helper(:a, :A) do
  { vars: { test: 1 }, methods: { a_method: 2 } }
end
# creates a method stub_a, which translates to A.new_stub(vars: { test: 1 }, methods: { a_method: 2 })

# given a defined template, the helper will automatically refer to it
StubFactory.define_template(:foo) do
  { test: 1 }
end

StubFactory.define_helper(:foo, :A) do
  { vars: { test2: 2 } }
end

a = stub_foo
a.class
# => A
a.test
# => 1
a.test2
# => 2

# all default values can be overwritten
a = stub_foo(vars: { test2: "bypassed" })
a.test2
# => "bypassed"

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request