1 files changed, 65 insertions, 0 deletions
diff --git a/spec/ruby/core/objectspace/_id2ref_spec.rb b/spec/ruby/core/objectspace/_id2ref_spec.rb
new file mode 100644
index 0000000000..a9fd526b7d
--- /dev/null
+++ b/spec/ruby/core/objectspace/_id2ref_spec.rb
@@ -0,0 +1,65 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "4.0" do
+  describe "ObjectSpace._id2ref" do
+    it "is deprecated" do
+      id = nil.object_id
+      -> {
+        ObjectSpace._id2ref(id)
+      }.should complain(/warning: ObjectSpace\._id2ref is deprecated/)
+    end
+  end
+end
+
+ruby_version_is ""..."4.0" do
+  describe "ObjectSpace._id2ref" do
+    it "converts an object id to a reference to the object" do
+      s = "I am a string"
+      r = ObjectSpace._id2ref(s.object_id)
+      r.should == s
+    end
+
+    it "retrieves true by object_id" do
+      ObjectSpace._id2ref(true.object_id).should == true
+    end
+
+    it "retrieves false by object_id" do
+      ObjectSpace._id2ref(false.object_id).should == false
+    end
+
+    it "retrieves nil by object_id" do
+      ObjectSpace._id2ref(nil.object_id).should == nil
+    end
+
+    it "retrieves a small Integer by object_id" do
+      ObjectSpace._id2ref(1.object_id).should == 1
+      ObjectSpace._id2ref((-42).object_id).should == -42
+    end
+
+    it "retrieves a large Integer by object_id" do
+      obj = 1 << 88
+      ObjectSpace._id2ref(obj.object_id).should.equal?(obj)
+    end
+
+    it "retrieves a Symbol by object_id" do
+      ObjectSpace._id2ref(:sym.object_id).should.equal?(:sym)
+    end
+
+    it "retrieves a String by object_id" do
+      obj = "str"
+      ObjectSpace._id2ref(obj.object_id).should.equal?(obj)
+    end
+
+    it "retrieves a frozen literal String by object_id" do
+      ObjectSpace._id2ref("frozen string literal _id2ref".freeze.object_id).should.equal?("frozen string literal _id2ref".freeze)
+    end
+
+    it "retrieves an Encoding by object_id" do
+      ObjectSpace._id2ref(Encoding::UTF_8.object_id).should.equal?(Encoding::UTF_8)
+    end
+
+    it 'raises RangeError when an object could not be found' do
+      proc { ObjectSpace._id2ref(1 << 60) }.should.raise(RangeError)
+    end
+  end
+end