fix: parse_xml should be in Blocklike

xblock/core.py

@@ -293,6 +293,54 @@ def fields(cls):  # pylint: disable=no-self-argument
 
         return fields
 
+    @classmethod
+    def parse_xml(cls, node, runtime, keys, id_generator):
+        """
+        Use `node` to construct a new block.
+
+        Arguments:
+            node (:class:`~xml.etree.ElementTree.Element`): The xml node to parse into an xblock.
+
+            runtime (:class:`.Runtime`): The runtime to use while parsing.
+
+            keys (:class:`.ScopeIds`): The keys identifying where this block
+                will store its data.
+
+            id_generator (:class:`.IdGenerator`): An object that will allow the
+                runtime to generate correct definition and usage ids for
+                children of this block.
+
+        """
+        block = runtime.construct_xblock_from_class(cls, keys)
+
+        # The base implementation: child nodes become child blocks.
+        # Or fields, if they belong to the right namespace.
+        for child in node:
+            if child.tag is etree.Comment:
+                continue
+            qname = etree.QName(child)
+            tag = qname.localname
+            namespace = qname.namespace
+
+            if namespace == XML_NAMESPACES["option"]:
+                cls._set_field_if_present(block, tag, child.text, child.attrib)
+            else:
+                block.runtime.add_node_as_child(block, child, id_generator)
+
+        # Attributes become fields.
+        for name, value in list(node.items()):  # lxml has no iteritems
+            cls._set_field_if_present(block, name, value, {})
+
+        # Text content becomes "content", if such a field exists.
+        if "content" in block.fields and block.fields["content"].scope == Scope.content:
+            text = node.text
+            if text:
+                text = text.strip()
+                if text:
+                    block.content = text
+
+        return block
+
     @classmethod
     def _set_field_if_present(cls, block, name, value, attrs):
         """

xblock/test/test_core_capabilities.py

@@ -118,7 +118,7 @@ class HasChildren(XBlock):
     class WithoutChildren(XBlock):
         """Toy class for hierarchy testing"""
 
-    class InheritedChildren(XBlock):
+    class InheritedChildren(HasChildren):
         """Toy class for hierarchy testing"""
 
     def test_children_metaclass(self):
@@ -181,7 +181,7 @@ def an_unsupported_view(self):
                 """
                 # pragma: no cover
 
-        test_xblock = SupportsDecoratorTester(runtime=None)
+        test_xblock = SupportsDecoratorTester(None, None, None)
 
         for view_name, functionality, expected_result in (
                 ("functionality_supported_view", "a_functionality", True),
@@ -213,7 +213,7 @@ def has_support(self, view, functionality):
                 """
                 return functionality == "a_functionality"
 
-        test_xblock = HasSupportOverrideTester(runtime=None)
+        test_xblock = HasSupportOverrideTester(None, None, None)
 
         for view_name, functionality, expected_result in (
                 ("functionality_supported_view", "a_functionality", True),