Add test for verifying memory management.

Author: cfis

test/test_node.rb

@@ -232,4 +232,20 @@ def test_set_content
     assert_equal("unescaped & string", node.content)
     assert_equal("<test>unescaped &amp; string</test>", node.to_s)
   end
+
+  def test_document_node_marks_document
+    GC.stress = true
+    node = create_document_child
+    assert_equal("child", node.name)
+    refute_nil(node.doc)
+  ensure
+    GC.stress = false
+  end
+
+  private
+
+  def create_document_child
+    doc = LibXML::XML::Document.string("<root><child/></root>")
+    doc.root.children.first
+  end
 end

test/test_node_edit.rb

@@ -155,4 +155,22 @@ def test_set_base
     assert_equal("<test xml:base=\"http://www.rubynet.org/\">\n  <num>one</num>\n  <num>two</num>\n  <num>three</num>\n</test>",
                  @doc.root.to_s)
   end
+
+  def test_detached_subtree_keeps_root_alive
+    GC.stress = true
+    node = create_detached_subtree_leaf
+    assert_equal("leaf", node.name)
+  ensure
+    GC.stress = false
+  end
+
+  private
+
+  def create_detached_subtree_leaf
+    root = LibXML::XML::Node.new("root")
+    mid = LibXML::XML::Node.new("mid")
+    root << mid
+    mid << LibXML::XML::Node.new("leaf")
+    root.children.first.children.first
+  end
 end

test/test_reader.rb

@@ -363,4 +363,21 @@ def test_string_encoding
       assert_equal(LibXML::XML::Encoding::NONE, reader.encoding)
     end
   end
+
+  def test_expand_gc_after_advance
+    GC.stress = true
+    expand_and_advance
+  ensure
+    GC.stress = false
+  end
+
+  private
+
+  def expand_and_advance
+    reader = LibXML::XML::Reader.string("<root><a/><b/></root>")
+    reader.read # root
+    reader.read # a
+    reader.expand
+    reader.next
+  end
 end