Module: RSpec::Rails::Mocks

Defined in:
lib/rspec/rails/mocks.rb

Defined Under Namespace

Modules: ActiveModelInstanceMethods, ActiveModelStubExtensions, ActiveRecordInstanceMethods, ActiveRecordStubExtensions

Instance Method Summary collapse

Instance Method Details

#mock_model(string_or_model_class, stubs = {}) ⇒ Object

Creates a test double representing string_or_model_class with common ActiveModel methods stubbed out. Additional methods may be easily stubbed (via add_stubs) if stubs is passed. This is most useful for impersonating models that don't exist yet.

NOTE that only ActiveModel's methods, plus new_record?, are stubbed out implicitly. new_record? returns the inverse of persisted?, and is present only for compatibility with extension frameworks that have yet to update themselves to the ActiveModel API (which declares persisted?, not new_record?).

string_or_model_class can be any of:

  • A String representing a Class that does not exist
  • A String representing a Class that extends ActiveModel::Naming
  • A Class that extends ActiveModel::Naming


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# File 'lib/rspec/rails/mocks.rb', line 89

def mock_model(string_or_model_class, stubs = {})
  if String === string_or_model_class
    if Object.const_defined?(string_or_model_class)
      model_class = Object.const_get(string_or_model_class)
    else
      model_class = Object.const_set(string_or_model_class, Class.new do
        extend ActiveModel::Naming
        def self.primary_key; :id; end
      end)
    end
  else
    model_class = string_or_model_class
  end

  unless model_class.kind_of? ActiveModel::Naming
    raise ArgumentError.new <<-EOM
The mock_model method can only accept as its first argument:
  * A String representing a Class that does not exist
  * A String representing a Class that extends ActiveModel::Naming
  * A Class that extends ActiveModel::Naming

It received #{model_class.inspect}
EOM
  end

  stubs = stubs.reverse_merge(:id => next_id)
  stubs = stubs.reverse_merge(:persisted? => !!stubs[:id],
                              :destroyed? => false,
                              :marked_for_destruction? => false,
                              :valid? => true,
                              :blank? => false)

  double("#{model_class.name}_#{stubs[:id]}", stubs).tap do |m|
    m.singleton_class.class_eval do
      include ActiveModelInstanceMethods
      include ActiveRecordInstanceMethods if defined?(ActiveRecord)
      include ActiveModel::Conversion
      include ActiveModel::Validations
    end
    if defined?(ActiveRecord)
      [:save, :update_attributes, :update].each do |key|
        if stubs[key] == false
          RSpec::Mocks.allow_message(m.errors, :empty?).and_return(false)
        end
      end
    end
    m.__send__(:__mock_proxy).instance_eval(<<-CODE, __FILE__, __LINE__)
      def @object.is_a?(other)
        #{model_class}.ancestors.include?(other)
      end unless #{stubs.has_key?(:is_a?)}

      def @object.kind_of?(other)
        #{model_class}.ancestors.include?(other)
      end unless #{stubs.has_key?(:kind_of?)}

      def @object.instance_of?(other)
        other == #{model_class}
      end unless #{stubs.has_key?(:instance_of?)}

      def @object.__model_class_has_column?(method_name)
        #{model_class}.respond_to?(:column_names) && #{model_class}.column_names.include?(method_name.to_s)
      end

      def @object.has_attribute?(attr_name)
        __model_class_has_column?(attr_name)
      end unless #{stubs.has_key?(:has_attribute?)}

      def @object.respond_to?(method_name, include_private=false)
        __model_class_has_column?(method_name) ? true : super
      end unless #{stubs.has_key?(:respond_to?)}

      def @object.method_missing(m, *a, &b)
        respond_to?(m) ? null_object? ? self : nil : super
      end

      def @object.class
        #{model_class}
      end unless #{stubs.has_key?(:class)}

      def @object.to_s
        "#{model_class.name}_#{to_param}"
      end unless #{stubs.has_key?(:to_s)}
    CODE
    yield m if block_given?
  end
end

#stub_model(model_class, stubs = {}) ⇒ Object

Creates an instance of Model with to_param stubbed using a generated value that is unique to each object. If Model is an ActiveRecord model, it is prohibited from accessing the database*.

For each key in stubs, if the model has a matching attribute (determined by respond_to?) it is simply assigned the submitted values. If the model does not have a matching attribute, the key/value pair is assigned as a stub return value using RSpec's mocking/stubbing framework.

persisted? is overridden to return the result of !id.nil? This means that by default persisted? will return true. If you want the object to behave as a new record, sending it as_new_record will set the id to nil. You can also explicitly set :id => nil, in which case persisted? will return false, but using as_new_record makes the example a bit more descriptive.

While you can use stub_model in any example (model, view, controller, helper), it is especially useful in view examples, which are inherently more state-based than interaction-based.

Examples:


stub_model(Person)
stub_model(Person).as_new_record
stub_model(Person, :to_param => 37)
stub_model(Person) {|person| person.first_name = "David"}


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# File 'lib/rspec/rails/mocks.rb', line 236

def stub_model(model_class, stubs={})
  model_class.new.tap do |m|
    m.extend ActiveModelStubExtensions
    if defined?(ActiveRecord) && model_class < ActiveRecord::Base
      m.extend ActiveRecordStubExtensions
      primary_key = model_class.primary_key.to_sym
      stubs = stubs.reverse_merge(primary_key => next_id)
      stubs = stubs.reverse_merge(:persisted? => !!stubs[primary_key])
    else
      stubs = stubs.reverse_merge(:id => next_id)
      stubs = stubs.reverse_merge(:persisted? => !!stubs[:id])
    end
    stubs = stubs.reverse_merge(:blank? => false)

    stubs.each do |message, return_value|
      if m.respond_to?("#{message}=")
        m.__send__("#{message}=", return_value)
      else
        RSpec::Mocks.allow_message(m, message).and_return(return_value)
      end
    end

    yield m if block_given?
  end
end