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require_relative '../../spec_helper'
describe "Enumerator.product" do
it "returns a Cartesian product of enumerators" do
enum = Enumerator.product(1..2, ["A", "B"])
enum.to_a.should == [[1, "A"], [1, "B"], [2, "A"], [2, "B"]]
end
it "accepts a list of enumerators of any length" do
enum = Enumerator.product(1..2)
enum.to_a.should == [[1], [2]]
enum = Enumerator.product(1..2, ["A"])
enum.to_a.should == [[1, "A"], [2, "A"]]
enum = Enumerator.product(1..2, ["A"], ["B"])
enum.to_a.should == [[1, "A", "B"], [2, "A", "B"]]
enum = Enumerator.product(2..3, ["A"], ["B"], ["C"])
enum.to_a.should == [[2, "A", "B", "C"], [3, "A", "B", "C"]]
end
it "returns an enumerator with an empty array when no arguments passed" do
enum = Enumerator.product
enum.to_a.should == [[]]
end
it "returns an instance of Enumerator::Product" do
enum = Enumerator.product
enum.class.should == Enumerator::Product
end
it "accepts infinite enumerators and returns infinite enumerator" do
enum = Enumerator.product(1.., ["A", "B"])
enum.take(5).should == [[1, "A"], [1, "B"], [2, "A"], [2, "B"], [3, "A"]]
enum.size.should == Float::INFINITY
end
it "accepts a block" do
elems = []
enum = Enumerator.product(1..2, ["X", "Y"]) { elems << _1 }
elems.should == [[1, "X"], [1, "Y"], [2, "X"], [2, "Y"]]
end
it "returns nil when a block passed" do
Enumerator.product(1..2) {}.should == nil
end
# https://bugs.ruby-lang.org/issues/19829
it "reject keyword arguments" do
-> {
Enumerator.product(1..3, foo: 1, bar: 2)
}.should raise_error(ArgumentError, "unknown keywords: :foo, :bar")
end
it "calls only #each_entry method on arguments" do
object = Object.new
def object.each_entry
yield 1
yield 2
end
enum = Enumerator.product(object, ["A", "B"])
enum.to_a.should == [[1, "A"], [1, "B"], [2, "A"], [2, "B"]]
end
it "raises NoMethodError when argument doesn't respond to #each_entry" do
-> {
Enumerator.product(Object.new).to_a
}.should raise_error(NoMethodError, /undefined method [`']each_entry' for/)
end
it "calls #each_entry lazily" do
Enumerator.product(Object.new).should be_kind_of(Enumerator)
end
it "iterates through consuming enumerator elements only once" do
a = [1, 2, 3]
i = 0
enum = Enumerator.new do |y|
while i < a.size
y << a[i]
i += 1
end
end
Enumerator.product(['a', 'b'], enum).to_a.should == [["a", 1], ["a", 2], ["a", 3]]
end
end
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