mspec/lib/mspec/matchers/be_nil.rb
class BeNilMatcher
def matches?(actual)
@actual = actual
@actual.nil?
end
def failure_message
["Expected #{@actual.inspect}", "to be nil"]
end
def negative_failure_message
["Expected #{@actual.inspect}", "not to be nil"]
end
end
class Object
def be_nil
BeNilMatcher.new
end
end