Xpath fixes

src/emeraldtree/ElementPath.py

@@ -106,6 +106,10 @@ def select(context, result):
         if parent_map is None:
             context.parent_map = parent_map = {}
             for p in context.root.iter():
+                try:
+                    iter(p)
+                except TypeError:
+                    continue
                 for e in p:
                     parent_map[e] = p
         for elem in result:
@@ -146,10 +150,21 @@ def select(context, result):
         token = next()
         if token[0] != "]":
             raise SyntaxError("invalid node predicate")
-        def select(context, result):
-            for elem in result:
-                if elem.find(tag) is not None:
-                    yield elem
+        try:
+            index = int(tag)
+        except ValueError:
+            def select(context, result):
+                for elem in result:
+                    if elem.find(tag) is not None:
+                        yield elem
+        else:
+            if index < 1:
+                raise SyntaxError("XPath position >= 1 expected")
+            def select(context, result):
+                for i, elem in enumerate(result):
+                    if i + 1 == index:
+                        yield elem
+                        break
     else:
         raise SyntaxError("invalid predicate")
     return select

src/emeraldtree/tests/test_tree.py

@@ -170,21 +170,25 @@ def test_Element_findall_bracketed_tag():
     assert result[0] is b1 # b1 has 'c' childs
 
 def test_Element_findall_dotdot():
-    pytest.skip('broken')
-    c1 = Element('c')
-    c2 = Element('c')
+    d1 = Element('d')
+    d2 = Element('d')
     text = "text"
-    b1 = Element('b', children=(c1, text, c2))
-    b2 = Element('b')
-    a1 = Element('a', children=(b1, b2, ))
-
+    c1 = Element('c', children=(d1, text, d2))
+    b1 = Element('b')
+    a1 = Element('a', children=(b1, c1, ))
+
+    # this is something we can not support.
+    # we do not have parent pointers and also we only have a context starting from c1 here.
+    # we give an empty result, similar to stdlib elementree, which has the same limitation.
     result = list(c1.findall('../c'))
-    assert len(result) == 2
+    assert len(result) == 0
+
+    # this is something we can support as we start at a higher element.
+    result = list(a1.findall('b/../c'))
+    assert len(result) == 1
     assert result[0] is c1
-    assert result[1] is c2
 
 def test_Element_findall_slashslash():
-    pytest.skip('broken')
     c1 = Element('c')
     c2 = Element('c')
     text = "text"
@@ -199,7 +203,6 @@ def test_Element_findall_slashslash():
     assert result[1] is c2
 
 def test_Element_findall_dotslashslash():
-    pytest.skip('broken')
     c1 = Element('c')
     c2 = Element('c')
     text = "text"
@@ -235,7 +238,6 @@ def test_Element_findall_attribute():
     assert len(result) == 0
 
 def test_Element_findall_position():
-    pytest.skip('not supported')
     c1 = Element('c')
     c2 = Element('c')
     text = "text"
@@ -251,6 +253,13 @@ def test_Element_findall_position():
     assert len(result) == 1
     assert result[0] is c2
 
+def test_Element_findall_position_invalid():
+    b1 = Element('b')
+    with pytest.raises(SyntaxError):
+        list(b1.findall('c[0]'))
+    with pytest.raises(SyntaxError):
+        list(b1.findall('c[-1]'))
+
 def test_Element_findtext_default():
     elem = Element('a')
     default_text = 'defaulttext'

src/emeraldtree/tree.py

@@ -355,7 +355,8 @@ def iter(self, tag=None):
                 for e in e.iter(tag):
                     yield e
             else:
-                yield e
+                if tag is None:
+                    yield e
 
     ##
     # Creates a text iterator.  The iterator loops over this element