1 files changed, 15 insertions, 0 deletions
diff --git a/activesupport/test/core_ext/enumerable_test.rb b/activesupport/test/core_ext/enumerable_test.rb
index 8d71320931..b63464a36a 100644
--- a/activesupport/test/core_ext/enumerable_test.rb
+++ b/activesupport/test/core_ext/enumerable_test.rb
@@ -179,6 +179,21 @@ class EnumerableTests < ActiveSupport::TestCase
                  payments.index_by.each(&:price))
   end
 
+  def test_index_with
+    payments = GenericEnumerable.new([ Payment.new(5), Payment.new(15), Payment.new(10) ])
+
+    assert_equal({ Payment.new(5) => 5, Payment.new(15) => 15, Payment.new(10) => 10 }, payments.index_with(&:price))
+
+    assert_equal({ title: nil, body: nil }, %i( title body ).index_with(nil))
+    assert_equal({ title: [], body: [] }, %i( title body ).index_with([]))
+    assert_equal({ title: {}, body: {} }, %i( title body ).index_with({}))
+
+    assert_equal Enumerator, payments.index_with.class
+    assert_nil payments.index_with.size
+    assert_equal 42, (1..42).index_with.size
+    assert_equal({ Payment.new(5) => 5, Payment.new(15) => 15, Payment.new(10) => 10 }, payments.index_with.each(&:price))
+  end
+
   def test_many
     assert_equal false, GenericEnumerable.new([]).many?
     assert_equal false, GenericEnumerable.new([ 1 ]).many?