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require 'test/unit'
class TestLazyEnumerator < Test::Unit::TestCase
class Step
include Enumerable
attr_reader :current, :args
def initialize(enum)
@enum = enum
@current = nil
@args = nil
end
def each(*args)
@args = args
@enum.each {|i| @current = i; yield i}
end
end
def test_initialize
assert_equal([1, 2, 3], [1, 2, 3].lazy.to_a)
assert_equal([1, 2, 3], Enumerator::Lazy.new([1, 2, 3]).to_a)
end
def test_each_args
a = Step.new(1..3)
assert_equal(1, a.lazy.each(4).first)
assert_equal([4], a.args)
end
def test_each_line
name = lineno = nil
File.open(__FILE__) do |f|
f.each("").map do |paragraph|
paragraph[/\A\s*(.*)/, 1]
end.find do |line|
if name = line[/^class\s+(\S+)/, 1]
lineno = f.lineno
true
end
end
end
assert_equal(self.class.name, name)
assert_operator(lineno, :>, 2)
name = lineno = nil
File.open(__FILE__) do |f|
f.lazy.each("").map do |paragraph|
paragraph[/\A\s*(.*)/, 1]
end.find do |line|
if name = line[/^class\s+(\S+)/, 1]
lineno = f.lineno
true
end
end
end
assert_equal(self.class.name, name)
assert_equal(2, lineno)
end
def test_select
a = Step.new(1..6)
assert_equal(4, a.select {|x| x > 3}.first)
assert_equal(6, a.current)
assert_equal(4, a.lazy.select {|x| x > 3}.first)
assert_equal(4, a.current)
a = Step.new(['word', nil, 1])
assert_raise(TypeError) {a.select {|x| "x"+x}.first}
assert_equal(nil, a.current)
assert_equal("word", a.lazy.select {|x| "x"+x}.first)
assert_equal("word", a.current)
end
def test_select_multiple_values
e = Enumerator.new { |yielder|
for i in 1..5
yielder.yield(i, i.to_s)
end
}
assert_equal([[2, "2"], [4, "4"]],
e.select {|x| x[0] % 2 == 0})
assert_equal([[2, "2"], [4, "4"]],
e.lazy.select {|x| x[0] % 2 == 0}.force)
end
def test_map
a = Step.new(1..3)
assert_equal(2, a.map {|x| x * 2}.first)
assert_equal(3, a.current)
assert_equal(2, a.lazy.map {|x| x * 2}.first)
assert_equal(1, a.current)
end
def test_flat_map
a = Step.new(1..3)
assert_equal(2, a.flat_map {|x| [x * 2]}.first)
assert_equal(3, a.current)
assert_equal(2, a.lazy.flat_map {|x| [x * 2]}.first)
assert_equal(1, a.current)
end
def test_flat_map_nested
a = Step.new(1..3)
assert_equal([1, "a"],
a.flat_map {|x| ("a".."c").map {|y| [x, y]}}.first)
assert_equal(3, a.current)
assert_equal([1, "a"],
a.lazy.flat_map {|x| ("a".."c").lazy.map {|y| [x, y]}}.first)
assert_equal(1, a.current)
end
def test_flat_map_to_ary
to_ary = Class.new {
def initialize(value)
@value = value
end
def to_ary
[:to_ary, @value]
end
}
assert_equal([:to_ary, 1, :to_ary, 2, :to_ary, 3],
[1, 2, 3].flat_map {|x| to_ary.new(x)})
assert_equal([:to_ary, 1, :to_ary, 2, :to_ary, 3],
[1, 2, 3].lazy.flat_map {|x| to_ary.new(x)}.force)
end
def test_flat_map_non_array
assert_equal(["1", "2", "3"], [1, 2, 3].flat_map {|x| x.to_s})
assert_equal(["1", "2", "3"], [1, 2, 3].lazy.flat_map {|x| x.to_s}.force)
end
def test_reject
a = Step.new(1..6)
assert_equal(4, a.reject {|x| x < 4}.first)
assert_equal(6, a.current)
assert_equal(4, a.lazy.reject {|x| x < 4}.first)
assert_equal(4, a.current)
a = Step.new(['word', nil, 1])
assert_equal(nil, a.reject {|x| x}.first)
assert_equal(1, a.current)
assert_equal(nil, a.lazy.reject {|x| x}.first)
assert_equal(nil, a.current)
end
def test_reject_multiple_values
e = Enumerator.new { |yielder|
for i in 1..5
yielder.yield(i, i.to_s)
end
}
assert_equal([[2, "2"], [4, "4"]],
e.reject {|x| x[0] % 2 != 0})
assert_equal([[2, "2"], [4, "4"]],
e.lazy.reject {|x| x[0] % 2 != 0}.force)
end
def test_grep
a = Step.new('a'..'f')
assert_equal('c', a.grep(/c/).first)
assert_equal('f', a.current)
assert_equal('c', a.lazy.grep(/c/).first)
assert_equal('c', a.current)
assert_equal(%w[a e], a.grep(proc {|x| /[aeiou]/ =~ x}))
assert_equal(%w[a e], a.lazy.grep(proc {|x| /[aeiou]/ =~ x}).to_a)
end
def test_grep_with_block
a = Step.new('a'..'f')
assert_equal('C', a.grep(/c/) {|i| i.upcase}.first)
assert_equal('C', a.lazy.grep(/c/) {|i| i.upcase}.first)
end
def test_grep_multiple_values
e = Enumerator.new { |yielder|
3.times { |i|
yielder.yield(i, i.to_s)
}
}
assert_equal([[2, "2"]], e.grep(proc {|x| x == [2, "2"]}))
assert_equal([[2, "2"]], e.lazy.grep(proc {|x| x == [2, "2"]}).force)
assert_equal(["22"],
e.lazy.grep(proc {|x| x == [2, "2"]}, &:join).force)
end
def test_zip
a = Step.new(1..3)
assert_equal([1, "a"], a.zip("a".."c").first)
assert_equal(3, a.current)
assert_equal([1, "a"], a.lazy.zip("a".."c").first)
assert_equal(1, a.current)
end
def test_zip_short_arg
a = Step.new(1..5)
assert_equal([5, nil], a.zip("a".."c").last)
assert_equal([5, nil], a.lazy.zip("a".."c").force.last)
end
def test_zip_without_arg
a = Step.new(1..3)
assert_equal([1], a.zip.first)
assert_equal(3, a.current)
assert_equal([1], a.lazy.zip.first)
assert_equal(1, a.current)
end
def test_zip_with_block
# zip should be eager when a block is given
a = Step.new(1..3)
ary = []
assert_equal(nil, a.lazy.zip("a".."c") {|x, y| ary << [x, y]})
assert_equal(a.zip("a".."c"), ary)
assert_equal(3, a.current)
end
def test_take
a = Step.new(1..10)
assert_equal(1, a.take(5).first)
assert_equal(5, a.current)
assert_equal(1, a.lazy.take(5).first)
assert_equal(1, a.current)
assert_equal((1..5).to_a, a.lazy.take(5).force)
assert_equal(5, a.current)
a = Step.new(1..10)
assert_equal([], a.lazy.take(0).force)
assert_equal(nil, a.current)
end
def test_take_recycle
bug6428 = '[ruby-dev:45634]'
a = Step.new(1..10)
take5 = a.lazy.take(5)
assert_equal((1..5).to_a, take5.force, bug6428)
assert_equal((1..5).to_a, take5.force, bug6428)
end
def test_take_while
a = Step.new(1..10)
assert_equal(1, a.take_while {|i| i < 5}.first)
assert_equal(5, a.current)
assert_equal(1, a.lazy.take_while {|i| i < 5}.first)
assert_equal(1, a.current)
assert_equal((1..4).to_a, a.lazy.take_while {|i| i < 5}.to_a)
end
def test_drop
a = Step.new(1..10)
assert_equal(6, a.drop(5).first)
assert_equal(10, a.current)
assert_equal(6, a.lazy.drop(5).first)
assert_equal(6, a.current)
assert_equal((6..10).to_a, a.lazy.drop(5).to_a)
end
def test_drop_while
a = Step.new(1..10)
assert_equal(5, a.drop_while {|i| i < 5}.first)
assert_equal(10, a.current)
assert_equal(5, a.lazy.drop_while {|i| i < 5}.first)
assert_equal(5, a.current)
assert_equal((5..10).to_a, a.lazy.drop_while {|i| i < 5}.to_a)
end
def test_drop_and_take
assert_equal([4, 5], (1..Float::INFINITY).lazy.drop(3).take(2).to_a)
end
def test_cycle
a = Step.new(1..3)
assert_equal("1", a.cycle(2).map(&:to_s).first)
assert_equal(3, a.current)
assert_equal("1", a.lazy.cycle(2).map(&:to_s).first)
assert_equal(1, a.current)
end
def test_cycle_with_block
# cycle should be eager when a block is given
a = Step.new(1..3)
ary = []
assert_equal(nil, a.lazy.cycle(2) {|i| ary << i})
assert_equal(a.cycle(2).to_a, ary)
assert_equal(3, a.current)
end
def test_cycle_chain
a = 1..3
assert_equal([1,2,3,1,2,3,1,2,3,1], a.lazy.cycle.take(10).force)
assert_equal([2,2,2,2,2,2,2,2,2,2], a.lazy.cycle.select {|x| x == 2}.take(10).force)
assert_equal([2,2,2,2,2,2,2,2,2,2], a.lazy.select {|x| x == 2}.cycle.take(10).force)
end
def test_force
assert_equal([1, 2, 3], (1..Float::INFINITY).lazy.take(3).force)
end
def test_inspect
assert_equal("#<Enumerator::Lazy: 1..10:each>",
Enumerator::Lazy.new(1..10).inspect)
assert_equal("#<Enumerator::Lazy: 1..10:cycle(2)>",
Enumerator::Lazy.new(1..10, :cycle, 2).inspect)
assert_equal("#<Enumerator::Lazy: 1..10>", (1..10).lazy.inspect)
assert_equal('#<Enumerator::Lazy: #<Enumerator: "foo":chars>>',
"foo".chars.lazy.inspect)
assert_equal("#<Enumerator::Lazy: #<Enumerator::Lazy: 1..10>:map>",
(1..10).lazy.map {}.inspect)
assert_equal("#<Enumerator::Lazy: #<Enumerator::Lazy: 1..10>:take(0)>",
(1..10).lazy.take(0).inspect)
assert_equal("#<Enumerator::Lazy: #<Enumerator::Lazy: 1..10>:take(3)>",
(1..10).lazy.take(3).inspect)
assert_equal('#<Enumerator::Lazy: #<Enumerator::Lazy: "a".."c">:grep(/b/)>',
("a".."c").lazy.grep(/b/).inspect)
assert_equal("#<Enumerator::Lazy: #<Enumerator::Lazy: 1..10>:cycle(3)>",
(1..10).lazy.cycle(3).inspect)
assert_equal("#<Enumerator::Lazy: #<Enumerator::Lazy: 1..10>:cycle>",
(1..10).lazy.cycle.inspect)
assert_equal("#<Enumerator::Lazy: #<Enumerator::Lazy: 1..10>:cycle(3)>",
(1..10).lazy.cycle(3).inspect)
l = (1..10).lazy.map {}.collect {}.flat_map {}.collect_concat {}.select {}.find_all {}.reject {}.grep(1).zip(?a..?c).take(10).take_while {}.drop(3).drop_while {}.cycle(3)
assert_equal(<<EOS.chomp, l.inspect)
#<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: #<Enumerator::Lazy: 1..10>:map>:collect>:flat_map>:collect_concat>:select>:find_all>:reject>:grep(1)>:zip("a".."c")>:take(10)>:take_while>:drop(3)>:drop_while>:cycle(3)>
EOS
end
def test_size
lazy = [1, 2, 3].lazy
assert_equal 3, lazy.size
assert_equal 42, Enumerator.new(42){}.lazy.size
end
end
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