module RSpec::Core::MemoizedHelpers
Private Class Methods
@api private
# File lib/rspec/core/memoized_helpers.rb, line 478 def self.define_helpers_on(example_group) example_group.send(:include, module_for(example_group)) end
@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 488 def self.get_constant_or_yield(example_group, name) if example_group.const_defined?(name) example_group.const_get(name) else yield end end
# File lib/rspec/core/memoized_helpers.rb, line 153 def self.included(mod) mod.extend(ClassMethods) end
@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 464 def self.module_for(example_group) get_constant_or_yield(example_group, :LetDefinitions) do mod = Module.new do include Module.new { example_group.const_set(:NamedSubjectPreventSuper, self) } end example_group.const_set(:LetDefinitions, mod) mod end end
Public Instance Methods
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 67 def should(matcher=nil, message=nil) RSpec::Expectations::PositiveExpectationHandler.handle_matcher(subject, matcher, message) end
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 81 def should_not(matcher=nil, message=nil) RSpec::Expectations::NegativeExpectationHandler.handle_matcher(subject, matcher, message) end
@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
@note Because `subject` is designed to create state that is reset between
each example, and `before(:all)` is designed to setup state that is shared across _all_ examples in an example group, `subject` is _not_ intended to be used in a `before(:all)` hook. RSpec 2.13.1 prints a warning when you reference a `subject` from `before(:all)` and we plan to have it raise an error in RSpec 3.
@see should
# File lib/rspec/core/memoized_helpers.rb, line 47 def subject __memoized.fetch(:subject) do __memoized[:subject] = begin described = described_class || self.class.description Class === described ? described.new : described end end end
Private Instance Methods
@private
# File lib/rspec/core/memoized_helpers.rb, line 88 def __memoized @__memoized ||= {} end