Test that recursive refs dump as aliases

3 files changed, 37 insertions, 0 deletions

diff --git a/test/psych/test_array.rb b/test/psych/test_array.rb
index 28b76da..a6be0ba 100644
--- a/test/psych/test_array.rb
+++ b/test/psych/test_array.rb
@@ -57,6 +57,19 @@ module Psych
       assert_cycle(@list)
     end
 
+    def test_recursive_array_uses_alias
+      @list << @list
+
+      expected = <<~eoyaml
+        --- &1
+        - :a: b
+        - foo
+        - *1
+      eoyaml
+
+      assert_equal expected, Psych.dump(@list)
+    end
+
     def test_cycle
       assert_cycle(@list)
     end
diff --git a/test/psych/test_hash.rb b/test/psych/test_hash.rb
index 5374781..43e4b8b 100644
--- a/test/psych/test_hash.rb
+++ b/test/psych/test_hash.rb
@@ -112,6 +112,18 @@ eoyml
       assert_equal({"foo"=>{"hello"=>"world"}, "bar"=>{"hello"=>"world"}}, hash)
     end
 
+    def test_recursive_hash_uses_alias
+      h = { }
+      h["recursive_reference"] = h
+
+      expected = <<~eoyaml
+        --- &1
+        recursive_reference: *1
+      eoyaml
+
+      assert_equal(expected, Psych.dump(h))
+    end
+
     def test_key_deduplication
       unless String.method_defined?(:-@) && (-("a" * 20)).equal?((-("a" * 20)))
         pend "This Ruby implementation doesn't support string deduplication"
diff --git a/test/psych/test_object.rb b/test/psych/test_object.rb
index 0faf6b2..648a3ca 100644
--- a/test/psych/test_object.rb
+++ b/test/psych/test_object.rb
@@ -41,5 +41,17 @@ module Psych
       assert_instance_of(Foo, loaded)
       assert_equal loaded, loaded.parent
     end
+
+    def test_cyclic_reference_uses_alias
+      foo = Foo.new(nil)
+      foo.parent = foo
+
+      expected = <<~eoyaml
+        --- &1 !ruby/object:Psych::Foo
+        parent: *1
+      eoyaml
+
+      assert_equal expected, Psych.dump(foo)
+    end
   end
 end