mspec/lib/mspec/matchers/be_nan.rb
class BeNaNMatcher
def matches?(actual)
@actual = actual
@actual.kind_of?(Float) && @actual.nan?
end
def failure_message
["Expected #{@actual}", "to be NaN"]
end
def negative_failure_message
["Expected #{@actual}", "not to be NaN"]
end
end
class Object
def be_nan
BeNaNMatcher.new
end
end