[Bug #20325] `Enumerator.product.size` is 0 if any size is 0

1 files changed, 8 insertions, 9 deletions

diff --git a/test/ruby/test_enumerator.rb b/test/ruby/test_enumerator.rb
index 825c191d87..7599d43463 100644
--- a/test/ruby/test_enumerator.rb
+++ b/test/ruby/test_enumerator.rb
@@ -953,11 +953,7 @@ class TestEnumerator < Test::Unit::TestCase
     assert_equal(true, e.is_lambda)
   end
 
-  def test_product
-    ##
-    ## Enumerator::Product
-    ##
-
+  def test_product_new
     # 0-dimensional
     e = Enumerator::Product.new
     assert_instance_of(Enumerator::Product, e)
@@ -994,15 +990,16 @@ class TestEnumerator < Test::Unit::TestCase
     e.each { |x,| heads << x }
     assert_equal [1, 1, 2, 2, 3, 3], heads
 
+    # Any enumerable is 0 size
+    assert_equal(0, Enumerator::Product.new([], 1..).size)
+
     # Reject keyword arguments
     assert_raise(ArgumentError) {
       Enumerator::Product.new(1..3, foo: 1, bar: 2)
     }
+  end
 
-    ##
-    ## Enumerator.product
-    ##
-
+  def test_s_product
     # without a block
     e = Enumerator.product(1..3, %w[a b])
     assert_instance_of(Enumerator::Product, e)
@@ -1029,6 +1026,8 @@ class TestEnumerator < Test::Unit::TestCase
     assert_equal(nil, e.size)
     assert_equal [[1, "a"], [1, "b"], [2, "a"], [2, "b"]], e.take(4)
 
+    assert_equal(0, Enumerator.product([], 1..).size)
+
     # Reject keyword arguments
     assert_raise(ArgumentError) {
       Enumerator.product(1..3, foo: 1, bar: 2)