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require 'abstract_unit'
require 'active_support/core_ext/array'
require 'active_support/core_ext/enumerable'
Payment = Struct.new(:price)
class SummablePayment < Payment
def +(p) self.class.new(price + p.price) end
end
class EnumerableTests < ActiveSupport::TestCase
class GenericEnumerable
include Enumerable
def initialize(values = [1, 2, 3])
@values = values
end
def each
@values.each{|v| yield v}
end
end
def test_sums
enum = GenericEnumerable.new([5, 15, 10])
assert_equal 30, enum.sum
assert_equal 60, enum.sum { |i| i * 2}
enum = GenericEnumerable.new(%w(a b c))
assert_equal 'abc', enum.sum
assert_equal 'aabbcc', enum.sum { |i| i * 2 }
payments = GenericEnumerable.new([ Payment.new(5), Payment.new(15), Payment.new(10) ])
assert_equal 30, payments.sum(&:price)
assert_equal 60, payments.sum { |p| p.price * 2 }
payments = GenericEnumerable.new([ SummablePayment.new(5), SummablePayment.new(15) ])
assert_equal SummablePayment.new(20), payments.sum
assert_equal SummablePayment.new(20), payments.sum { |p| p }
end
def test_nil_sums
expected_raise = TypeError
assert_raise(expected_raise) { GenericEnumerable.new([5, 15, nil]).sum }
payments = GenericEnumerable.new([ Payment.new(5), Payment.new(15), Payment.new(10), Payment.new(nil) ])
assert_raise(expected_raise) { payments.sum(&:price) }
assert_equal 60, payments.sum { |p| p.price.to_i * 2 }
end
def test_empty_sums
assert_equal 0, GenericEnumerable.new([]).sum
assert_equal 0, GenericEnumerable.new([]).sum { |i| i + 10 }
assert_equal Payment.new(0), GenericEnumerable.new([]).sum(Payment.new(0))
end
def test_range_sums
assert_equal 20, (1..4).sum { |i| i * 2 }
assert_equal 10, (1..4).sum
assert_equal 10, (1..4.5).sum
assert_equal 6, (1...4).sum
assert_equal 'abc', ('a'..'c').sum
assert_equal 50_000_005_000_000, (0..10_000_000).sum
assert_equal 0, (10..0).sum
assert_equal 5, (10..0).sum(5)
assert_equal 10, (10..10).sum
assert_equal 42, (10...10).sum(42)
end
def test_index_by
payments = GenericEnumerable.new([ Payment.new(5), Payment.new(15), Payment.new(10) ])
assert_equal({ 5 => Payment.new(5), 15 => Payment.new(15), 10 => Payment.new(10) },
payments.index_by { |p| p.price })
assert_equal Enumerator, payments.index_by.class
if Enumerator.method_defined? :size
assert_equal nil, payments.index_by.size
assert_equal 42, (1..42).index_by.size
end
assert_equal({ 5 => Payment.new(5), 15 => Payment.new(15), 10 => Payment.new(10) },
payments.index_by.each { |p| p.price })
end
def test_many
assert_equal false, GenericEnumerable.new([] ).many?
assert_equal false, GenericEnumerable.new([ 1 ] ).many?
assert_equal true, GenericEnumerable.new([ 1, 2 ] ).many?
assert_equal false, GenericEnumerable.new([] ).many? {|x| x > 1 }
assert_equal false, GenericEnumerable.new([ 2 ] ).many? {|x| x > 1 }
assert_equal false, GenericEnumerable.new([ 1, 2 ] ).many? {|x| x > 1 }
assert_equal true, GenericEnumerable.new([ 1, 2, 2 ]).many? {|x| x > 1 }
end
def test_many_iterates_only_on_what_is_needed
infinity = 1.0/0.0
very_long_enum = 0..infinity
assert_equal true, very_long_enum.many?
assert_equal true, very_long_enum.many?{|x| x > 100}
end
def test_exclude?
assert_equal true, GenericEnumerable.new([ 1 ]).exclude?(2)
assert_equal false, GenericEnumerable.new([ 1 ]).exclude?(1)
end
end
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