facho/facho.py: maneja rutas relativas.

FossilOrigin-Name: cd97ead663dbbc1e2252f83da6e9cf17f9b3ae32e0ff411427ec62ad3658e89d

facho/facho.py

@@ -173,12 +173,17 @@ class FachoXML:
         xpath = self._path_xpath_for(xpath)
         node_paths = xpath.split('/')
         node_paths.pop(0) #remove empty /
+        root_tag = node_paths.pop(0)
 
-        root_node = self.builder.build_from_expression(node_paths[0])
+        root_node = self.builder.build_from_expression(root_tag)
+        if xpath.startswith('.'):
+            # restaurar ya que no es la raiz y asignar actual como raiz
+            node_paths.insert(0, root_tag)
+            root_node = self.root
+            
         if not self.builder.same_tag(root_node.tag, self.root.tag):
+            
             raise ValueError('xpath %s must be absolute to /%s' % (xpath, self.root.tag))
-        else:
-            node_paths.pop(0)
 
         # crea jerarquia segun xpath indicado
         parent = None

tests/test_facho.py

@@ -150,3 +150,23 @@ def test_facho_xml_get_element_text_next_child():
     line = xml.fragment('/Invoice/Line', append=True)
     line.set_element('/Line/Quantity', 6)
     assert line.get_element_text('/Line[2]/Quantity', format_=int) == 6
+
+
+def test_facho_xml_set_element_relative():
+    xml = facho.FachoXML('Invoice')
+    xml.set_element('./ID', 'ABC123')
+
+    assert xml.get_element_text('/Invoice/ID') == 'ABC123'
+
+def test_facho_xml_set_element_relative_with_namespace():
+    xml = facho.FachoXML('{%s}Invoice' % ('http://www.dian.gov.co/contratos/facturaelectronica/v1'),
+                         nsmap={'fe': 'http://www.dian.gov.co/contratos/facturaelectronica/v1'})
+    xml.set_element('./ID', 'ABC123')
+
+    assert xml.get_element_text('/fe:Invoice/ID') == 'ABC123'
+
+def test_facho_xml_fragment_relative():
+    xml = facho.FachoXML('root')
+    invoice = xml.fragment('./Invoice')
+    invoice.set_element('./Id', 1)
+    assert xml.tostring() == '<root><Invoice><Id>1</Id></Invoice></root>'