Add Class#descendants

Doesn't include receiver or singleton classes.

Implements [Feature #14394]

Co-authored-by: fatkodima <fatkodima123@gmail.com>
Co-authored-by: Benoit Daloze <eregontp@gmail.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/test/ruby/test_class.rb b/test/ruby/test_class.rb
index 368c046261..96bca08601 100644
--- a/test/ruby/test_class.rb
+++ b/test/ruby/test_class.rb
@@ -737,4 +737,22 @@ class TestClass < Test::Unit::TestCase
     c = Class.new.freeze
     assert_same(c, Module.new.const_set(:Foo, c))
   end
+
+  def test_descendants
+    c = Class.new
+    sc = Class.new(c)
+    ssc = Class.new(sc)
+    [c, sc, ssc].each do |k|
+      k.include Module.new
+      k.new.define_singleton_method(:force_singleton_class){}
+    end
+    assert_equal([sc, ssc], c.descendants)
+    assert_equal([ssc], sc.descendants)
+    assert_equal([], ssc.descendants)
+
+    object_descendants = Object.descendants
+    assert_include(object_descendants, c)
+    assert_include(object_descendants, sc)
+    assert_include(object_descendants, ssc)
+  end
 end