Backport minidom attribute tests from default (73c76466cf44).

Some minidom code changed between 3.2 and 3.3, so to be sure to avoid
differenced in behavior I’m backporting these tests added by MvL.

Lib/test/test_minidom.py

@@ -350,13 +350,31 @@ class MinidomTest(unittest.TestCase):
     def testGetAttrList(self):
         pass
 
-    def testGetAttrValues(self): pass
+    def testGetAttrValues(self):
+        pass
 
-    def testGetAttrLength(self): pass
+    def testGetAttrLength(self):
+        pass
 
-    def testGetAttribute(self): pass
+    def testGetAttribute(self):
+        dom = Document()
+        child = dom.appendChild(
+            dom.createElementNS("http://www.python.org", "python:abc"))
+        self.assertEqual(child.getAttribute('missing'), '')
 
-    def testGetAttributeNS(self): pass
+    def testGetAttributeNS(self):
+        dom = Document()
+        child = dom.appendChild(
+                dom.createElementNS("http://www.python.org", "python:abc"))
+        child.setAttributeNS("http://www.w3.org", "xmlns:python",
+                                                "http://www.python.org")
+        self.assertEqual(child.getAttributeNS("http://www.w3.org", "python"),
+            'http://www.python.org')
+        self.assertEqual(child.getAttributeNS("http://www.w3.org", "other"),
+            '')
+        child2 = child.appendChild(dom.createElement('abc'))
+        self.assertEqual(child2.getAttributeNS("http://www.python.org", "missing"),
+                         '')
 
     def testGetAttributeNode(self): pass