refactor: move xmodule folder to root

- Moving xmodule folder to root as we're dissolving sub-projects of common folder in edx-platform
    - More info: https://openedx.atlassian.net/browse/BOM-2579
- -e common/lib/xmodule has been removed from the requirements as xmodule has itself become the part of edx-platform and not being installed through requirements
- The test files common/lib/xmodule/test_files/ have been removed as they are not being used anymore

xmodule/modulestore/tests/test_xml.py

@@ -0,0 +1,161 @@
+"""
+Tests around our XML modulestore, including importing
+well-formed and not-well-formed XML.
+"""
+
+
+import os.path
+from glob import glob
+from unittest.mock import Mock, patch
+
+import pytest
+from django.test import TestCase
+from opaque_keys.edx.keys import CourseKey
+from opaque_keys.edx.locator import CourseLocator
+
+from xmodule.modulestore import ModuleStoreEnum
+from xmodule.modulestore.tests.test_modulestore import check_has_course_method
+from xmodule.modulestore.tests.utils import TILDA_FILES_DICT, add_temp_files_from_dict, remove_temp_files_from_list
+from xmodule.modulestore.xml import XMLModuleStore
+from xmodule.tests import DATA_DIR
+from xmodule.x_module import XModuleMixin
+
+
+def glob_tildes_at_end(path):
+    """
+    A wrapper for the `glob.glob` function, but it always returns
+    files that end in a tilde (~) at the end of the list of results.
+    """
+    result = glob(path)
+    with_tildes = [f for f in result if f.endswith("~")]
+    no_tildes = [f for f in result if not f.endswith("~")]
+    return no_tildes + with_tildes
+
+
+class TestXMLModuleStore(TestCase):
+    """
+    Test around the XML modulestore
+    """
+
+    @patch('xmodule.tabs.CourseTabList.initialize_default', Mock())
+    def test_unicode_chars_in_xml_content(self):
+        # edX/full/6.002_Spring_2012 has non-ASCII chars, and during
+        # uniquification of names, would raise a UnicodeError. It no longer does.
+
+        # Ensure that there really is a non-ASCII character in the course.
+        with open(os.path.join(DATA_DIR, "toy/sequential/vertical_sequential.xml"), 'rb') as xmlf:
+            xml = xmlf.read()
+            with pytest.raises(UnicodeDecodeError):
+                xml.decode('ascii')
+
+        # Load the course, but don't make error modules.  This will succeed,
+        # but will record the errors.
+        modulestore = XMLModuleStore(
+            DATA_DIR,
+            source_dirs=['toy'],
+            xblock_mixins=(XModuleMixin,),
+            load_error_modules=False)
+
+        # Look up the errors during load. There should be none.
+        errors = modulestore.get_course_errors(CourseKey.from_string("edX/toy/2012_Fall"))
+        assert errors == []
+
+    def test_get_courses_for_wiki(self):
+        """
+        Test the get_courses_for_wiki method
+        """
+        store = XMLModuleStore(DATA_DIR, source_dirs=['toy', 'simple'])
+        for course in store.get_courses():
+            course_locations = store.get_courses_for_wiki(course.wiki_slug)
+            assert len(course_locations) == 1
+            assert course.location.course_key in course_locations
+
+        course_locations = store.get_courses_for_wiki('no_such_wiki')
+        assert len(course_locations) == 0
+
+        # now set toy course to share the wiki with simple course
+        toy_course = store.get_course(CourseKey.from_string('edX/toy/2012_Fall'))
+        toy_course.wiki_slug = 'simple'
+
+        course_locations = store.get_courses_for_wiki('toy')
+        assert len(course_locations) == 0
+
+        course_locations = store.get_courses_for_wiki('simple')
+        assert len(course_locations) == 2
+        for course_number in ['toy', 'simple']:
+            assert CourseKey.from_string('/'.join(['edX', course_number, '2012_Fall'])) in course_locations
+
+    def test_has_course(self):
+        """
+        Test the has_course method
+        """
+        check_has_course_method(
+            XMLModuleStore(DATA_DIR, source_dirs=['toy', 'simple']),
+            CourseKey.from_string('edX/toy/2012_Fall'),
+            locator_key_fields=CourseLocator.KEY_FIELDS
+        )
+
+    def test_branch_setting(self):
+        """
+        Test the branch setting context manager
+        """
+        store = XMLModuleStore(DATA_DIR, source_dirs=['toy'])
+        course = store.get_courses()[0]
+
+        # XML store allows published_only branch setting
+        with store.branch_setting(ModuleStoreEnum.Branch.published_only, course.id):
+            store.get_item(course.location)
+
+        # XML store does NOT allow draft_preferred branch setting
+        with pytest.raises(ValueError):
+            with store.branch_setting(ModuleStoreEnum.Branch.draft_preferred, course.id):
+                # verify that the above context manager raises a ValueError
+                pass  # pragma: no cover
+
+    @patch('xmodule.modulestore.xml.log')
+    def test_dag_course(self, mock_logging):
+        """
+        Test a course whose structure is not a tree.
+        """
+        store = XMLModuleStore(
+            DATA_DIR,
+            source_dirs=['xml_dag'],
+            xblock_mixins=(XModuleMixin,),
+        )
+        course_key = store.get_courses()[0].id
+
+        mock_logging.warning.assert_called_with(
+            "%s has more than one definition", course_key.make_usage_key('discussion', 'duplicate_def')
+        )
+
+        shared_item_loc = course_key.make_usage_key('html', 'toyhtml')
+        shared_item = store.get_item(shared_item_loc)
+        parent = shared_item.get_parent()
+        assert parent is not None, 'get_parent failed to return a value'
+        parent_loc = course_key.make_usage_key('vertical', 'vertical_test')
+        assert parent.location == parent_loc
+        assert shared_item.location in [x.location for x in parent.get_children()]
+        # ensure it's still a child of the other parent even tho it doesn't claim the other parent as its parent
+        other_parent_loc = course_key.make_usage_key('vertical', 'zeta')
+        other_parent = store.get_item(other_parent_loc)
+        # children rather than get_children b/c the instance returned by get_children != shared_item
+        assert shared_item_loc in other_parent.children
+
+
+class TestModuleStoreIgnore(TestXMLModuleStore):  # lint-amnesty, pylint: disable=missing-class-docstring, test-inherits-tests
+    course_dir = DATA_DIR / "course_ignore"
+
+    def setUp(self):
+        super().setUp()
+        self.addCleanup(remove_temp_files_from_list, list(TILDA_FILES_DICT.keys()), self.course_dir / "static")
+        add_temp_files_from_dict(TILDA_FILES_DICT, self.course_dir / "static")
+
+    @patch("xmodule.modulestore.xml.glob.glob", side_effect=glob_tildes_at_end)
+    def test_tilde_files_ignored(self, _fake_glob):
+        modulestore = XMLModuleStore(DATA_DIR, source_dirs=['course_ignore'], load_error_modules=False)
+        about_location = CourseKey.from_string('edX/course_ignore/2014_Fall').make_usage_key(
+            'about', 'index',
+        )
+        about_module = modulestore.get_item(about_location)
+        assert 'GREEN' in about_module.data
+        assert 'RED' not in about_module.data