Fix #228: make sure the lxml treewalker works with trees from lxml (#256)

r=nobody!

Author: gsnedders

html5lib/tests/test_treewalkers.py

@@ -2,6 +2,11 @@
 
 import pytest
 
+try:
+    import lxml.etree
+except ImportError:
+    pass
+
 from .support import treeTypes
 
 from html5lib import html5parser, treewalkers
@@ -93,3 +98,19 @@ def test_treewalker_six_mix():
     for tree in sorted(treeTypes.items()):
         for intext, attrs, expected in sm_tests:
             yield runTreewalkerEditTest, intext, expected, attrs, tree
+
+
+@pytest.mark.skipif(treeTypes["lxml"] is None, reason="lxml not importable")
+def test_lxml_xml():
+    expected = [
+        {'data': {}, 'name': 'div', 'namespace': None, 'type': 'StartTag'},
+        {'data': {}, 'name': 'div', 'namespace': None, 'type': 'StartTag'},
+        {'name': 'div', 'namespace': None, 'type': 'EndTag'},
+        {'name': 'div', 'namespace': None, 'type': 'EndTag'}
+    ]
+
+    lxmltree = lxml.etree.fromstring('<div><div></div></div>')
+    walker = treewalkers.getTreeWalker('lxml')
+    output = Lint(walker(lxmltree))
+
+    assert list(output) == expected

html5lib/treewalkers/lxmletree.py

@@ -22,13 +22,20 @@ class Root(object):
     def __init__(self, et):
         self.elementtree = et
         self.children = []
-        if et.docinfo.internalDTD:
-            self.children.append(Doctype(self,
-                                         ensure_str(et.docinfo.root_name),
-                                         ensure_str(et.docinfo.public_id),
-                                         ensure_str(et.docinfo.system_url)))
-        root = et.getroot()
-        node = root
+
+        try:
+            if et.docinfo.internalDTD:
+                self.children.append(Doctype(self,
+                                             ensure_str(et.docinfo.root_name),
+                                             ensure_str(et.docinfo.public_id),
+                                             ensure_str(et.docinfo.system_url)))
+        except AttributeError:
+            pass
+
+        try:
+            node = et.getroot()
+        except AttributeError:
+            node = et
 
         while node.getprevious() is not None:
             node = node.getprevious()
@@ -118,12 +125,12 @@ def __len__(self):
 class TreeWalker(_base.NonRecursiveTreeWalker):
     def __init__(self, tree):
         # pylint:disable=redefined-variable-type
-        if hasattr(tree, "getroot"):
-            self.fragmentChildren = set()
-            tree = Root(tree)
-        elif isinstance(tree, list):
+        if isinstance(tree, list):
             self.fragmentChildren = set(tree)
             tree = FragmentRoot(tree)
+        else:
+            self.fragmentChildren = set()
+            tree = Root(tree)
         _base.NonRecursiveTreeWalker.__init__(self, tree)
         self.filter = ihatexml.InfosetFilter()