1 files changed, 93 insertions, 0 deletions
diff --git a/test/psych/test_data.rb b/test/psych/test_data.rb
new file mode 100644
index 0000000000..5e340c580a
--- /dev/null
+++ b/test/psych/test_data.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+require_relative 'helper'
+
+class PsychDataWithIvar < Data.define(:foo)
+  attr_reader :bar
+  def initialize(**)
+    @bar = 'hello'
+    super
+  end
+end unless RUBY_VERSION < "3.2"
+
+module Psych
+  class TestData < TestCase
+    class SelfReferentialData < Data.define(:foo)
+      attr_accessor :ref
+      def initialize(foo:)
+        @ref = self
+        super
+      end
+    end unless RUBY_VERSION < "3.2"
+
+    def setup
+      omit "Data requires ruby >= 3.2" if RUBY_VERSION < "3.2"
+    end
+
+    # TODO: move to another test?
+    def test_dump_data
+      assert_equal <<~eoyml, Psych.dump(PsychDataWithIvar["bar"])
+        --- !ruby/data-with-ivars:PsychDataWithIvar
+        members:
+          foo: bar
+        ivars:
+          "@bar": hello
+      eoyml
+    end
+
+    def test_self_referential_data
+      circular = SelfReferentialData.new("foo")
+
+      loaded = Psych.unsafe_load(Psych.dump(circular))
+      assert_instance_of(SelfReferentialData, loaded.ref)
+
+      assert_equal(circular, loaded)
+      assert_same(loaded, loaded.ref)
+    end
+
+    def test_roundtrip
+      thing = PsychDataWithIvar.new("bar")
+      data = Psych.unsafe_load(Psych.dump(thing))
+
+      assert_equal "hello", data.bar
+      assert_equal "bar",   data.foo
+    end
+
+    def test_load
+      obj = Psych.unsafe_load(<<~eoyml)
+        --- !ruby/data-with-ivars:PsychDataWithIvar
+        members:
+          foo: bar
+        ivars:
+          "@bar": hello
+      eoyml
+
+      assert_equal "hello", obj.bar
+      assert_equal "bar",   obj.foo
+    end
+
+    def test_members_must_be_identical
+      TestData.const_set :D, Data.define(:a, :b)
+      d = Psych.dump(TestData::D.new(1, 2))
+
+      # more members
+      TestData.send :remove_const, :D
+      TestData.const_set :D, Data.define(:a, :b, :c)
+      e = assert_raise(ArgumentError) { Psych.unsafe_load d }
+      assert_equal 'missing keyword: :c', e.message
+
+      # less members
+      TestData.send :remove_const, :D
+      TestData.const_set :D, Data.define(:a)
+      e = assert_raise(ArgumentError) { Psych.unsafe_load d }
+      assert_equal 'unknown keyword: :b', e.message
+
+      # completely different members
+      TestData.send :remove_const, :D
+      TestData.const_set :D, Data.define(:a, :c)
+      e = assert_raise(ArgumentError) { Psych.unsafe_load d }
+      assert_include e.message, 'keyword:'
+    ensure
+      TestData.send :remove_const, :D
+    end
+  end
+end