module RSpec::Core::MemoizedHelpers

Private Class Methods

get_constant_or_yield(example_group, name) { || ... } click to toggle source

@api private

Gets the named constant or yields. On 1.8, const_defined? / const_get do not take into account the inheritance hierarchy.

# File lib/rspec/core/memoized_helpers.rb, line 475
def self.get_constant_or_yield(example_group, name)
  if example_group.const_defined?(name)
    example_group.const_get(name)
  else
    yield
  end
end
included(mod) click to toggle source
# File lib/rspec/core/memoized_helpers.rb, line 141
def self.included(mod)
  mod.extend(ClassMethods)

  # This logic defines an implicit subject
  mod.subject do
    described = described_class || self.class.description
    Class === described ? described.new : described
  end
end
module_for(example_group) click to toggle source

@api private

Gets the LetDefinitions module. The module is mixed into the example group and is used to hold all let definitions. This is done so that the block passed to `let` can be forwarded directly on to `define_method`, so that all method constructs (including `super` and `return`) can be used in a `let` block.

The memoization is provided by a method definition on the example group that supers to the LetDefinitions definition in order to get the value to memoize.

# File lib/rspec/core/memoized_helpers.rb, line 450
def self.module_for(example_group)
  get_constant_or_yield(example_group, :LetDefinitions) do
    mod = Module.new do
      include Module.new {
        public_class_method :define_method
        example_group.const_set(:NamedSubjectPreventSuper, self)
      }

      # Expose `define_method` as a public method, so we can
      # easily use it below.
      public_class_method :define_method
    end

    example_group.__send__(:include, mod)
    example_group.const_set(:LetDefinitions, mod)
    mod
  end
end

Public Instance Methods

should(matcher=nil, message=nil) click to toggle source

When `should` is called with no explicit receiver, the call is delegated to the object returned by `subject`. Combined with an implicit subject this supports very concise expressions.

@example

describe Person do
  it { should be_eligible_to_vote }
end

@see subject

# File lib/rspec/core/memoized_helpers.rb, line 56
def should(matcher=nil, message=nil)
  RSpec::Expectations::PositiveExpectationHandler.handle_matcher(subject, matcher, message)
end
should_not(matcher=nil, message=nil) click to toggle source

Just like `should`, `should_not` delegates to the subject (implicit or explicit) of the example group.

@example

describe Person do
  it { should_not be_eligible_to_vote }
end

@see subject

# File lib/rspec/core/memoized_helpers.rb, line 70
def should_not(matcher=nil, message=nil)
  RSpec::Expectations::NegativeExpectationHandler.handle_matcher(subject, matcher, message)
end
subject() click to toggle source

@note `subject` was contributed by Joe Ferris to support the one-liner

syntax embraced by shoulda matchers:

    describe Widget do
      it { should validate_presence_of(:name) }
    end

While the examples below demonstrate how to use `subject`
explicitly in examples, we recommend that you define a method with
an intention revealing name instead.

@example

# explicit declaration of subject
describe Person do
  subject { Person.new(:birthdate => 19.years.ago) }
  it "should be eligible to vote" do
    subject.should be_eligible_to_vote
    # ^ ^ explicit reference to subject not recommended
  end
end

# implicit subject => { Person.new }
describe Person do
  it "should be eligible to vote" do
    subject.should be_eligible_to_vote
    # ^ ^ explicit reference to subject not recommended
  end
end

# one-liner syntax - should is invoked on subject
describe Person do
  it { should be_eligible_to_vote }
end

@see should

# File lib/rspec/core/memoized_helpers.rb, line 40
def subject
  raise NotImplementedError, 'This definition is here for documentation purposes only'
    ' - it is overriden anyway below when this module gets included.'
end

Private Instance Methods

__memoized() click to toggle source

@private

# File lib/rspec/core/memoized_helpers.rb, line 77
def __memoized
  @__memoized ||= {}
end