/
be_within.rb
46 lines (38 loc) · 1.09 KB
/
be_within.rb
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module RSpec
module Matchers
module BuiltIn
class BeWithin
def initialize(delta)
@delta = delta
end
def matches?(actual)
@actual = actual
raise needs_expected unless defined? @expected
raise needs_subtractable unless @actual.respond_to? :-
(@actual - @expected).abs <= @delta
end
alias == matches?
def of(expected)
@expected = expected
self
end
def failure_message_for_should
"expected #{@actual} to #{description}"
end
def failure_message_for_should_not
"expected #{@actual} not to #{description}"
end
def description
"be within #{@delta} of #{@expected}"
end
private
def needs_subtractable
ArgumentError.new "The actual value (#{@actual.inspect}) must respond to `-`"
end
def needs_expected
ArgumentError.new "You must set an expected value using #of: be_within(#{@delta}).of(expected_value)"
end
end
end
end
end