[gxml] Added tests for parent in xDocument

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit d8d44c399f9ef75797ad6c3a70bab3a507f58ba3
Author: Daniel Espinosa <esodan gmail com>
Date:   Thu Feb 18 21:47:31 2016 -0600

    Added tests for parent in xDocument

 gxml/libxml-Node.vala  |    7 ++++++-
 test/AttrTest.vala     |    6 ++++++
 test/DocumentTest.vala |    4 ++++
 test/ElementTest.vala  |    8 ++++++++
 4 files changed, 24 insertions(+), 1 deletions(-)
---
diff --git a/gxml/libxml-Node.vala b/gxml/libxml-Node.vala
index 0c1c471..820c6d0 100644
--- a/gxml/libxml-Node.vala
+++ b/gxml/libxml-Node.vala
@@ -509,6 +509,11 @@ namespace GXml {
                public GXml.NodeType type_node { get { return node_type; } }
                public virtual string to_string () { return stringify (); }
                public GXml.Document document { get { return this.owner_document; } }
-               public virtual GXml.Node parent { owned get { return parent_node.ref () as GXml.Node; } }
+               public virtual GXml.Node parent {
+                       owned get {
+                               if (parent_node == null) return null;
+                               return parent_node.ref () as GXml.Node; 
+                       } 
+               }
        }
 }
diff --git a/test/AttrTest.vala b/test/AttrTest.vala
index 0b4fad3..b02e992 100644
--- a/test/AttrTest.vala
+++ b/test/AttrTest.vala
@@ -170,5 +170,11 @@ class AttrTest : GXmlTest {
                                attr.remove_child (attr.child_nodes.last ());
                                assert (attr.value == "");
                        });
+               Test.add_func ("/gxml/attribute/parent", () => {
+                       var doc = new xDocument.from_string ("<root attr=\"val\"><child/></root>");
+                       assert (doc.root != null);
+                       assert (doc.root.attrs["attr"] != null);
+                       assert (doc.root.attrs["attr"].parent == null);
+               });
        }
 }
diff --git a/test/DocumentTest.vala b/test/DocumentTest.vala
index e113b2d..5a02e0e 100644
--- a/test/DocumentTest.vala
+++ b/test/DocumentTest.vala
@@ -443,6 +443,10 @@ class DocumentTest : GXmlTest {
                                /* more thorough test exists in xElement, since right now
                                   xDocument uses that one */
                        });
+               Test.add_func ("/gxml/document/parent", () => {
+                               var doc = new xDocument ();
+                               assert (doc.parent == null);
+                       });
                Test.add_func ("/gxml/document/to_string", () => {
                                xDocument doc = get_doc ();
                                assert (doc.to_string () == "<?xml version=\"1.0\"?>
diff --git a/test/ElementTest.vala b/test/ElementTest.vala
index e5a9c61..43caed0 100644
--- a/test/ElementTest.vala
+++ b/test/ElementTest.vala
@@ -454,5 +454,13 @@ class ElementTest : GXmlTest  {
                                assert_not_reached ();
                        }
                });
+               Test.add_func ("/gxml/element/parent", () => {
+                       var doc = new xDocument.from_string ("<root><child/></root>");
+                       assert (doc.root != null);
+                       assert (doc.root.children[0] != null);
+                       assert (doc.root.children[0].parent != null);
+                       assert (doc.root.children[0].parent.name == "root");
+                       assert (doc.root.parent == null);
+               });
        }
 }