chore: simplify test cases and refactor docstrings

openedx/core/djangolib/markup.py

@@ -17,43 +17,35 @@
 
 class HTMLCleaner(Cleaner):
     """
-    HTMLCleaner extends lxml.html.clean.Cleaner to sanitize HTML content while preserving valid URLs
-    and removing unsafe JavaScript links.
-
-    Attributes:
-    -----------
-    _is_url : Callable[[str], Optional[re.Match]]
-        A regular expression pattern used to identify valid URLs. This pattern matches strings that
-        start with 'http', 'https', 'ftp', or 'file' schemes, case-insensitively.
+    HTMLCleaner extends lxml.html.clean.Cleaner to sanitize HTML content while preserving
+    valid URLs and removing unsafe JavaScript links.
     """
     def _remove_javascript_link(self, link: str):
         """
-        Checks if the given link is a valid URL. If it is, the link is returned unchanged.
-        Otherwise, the method delegates to the parent class's method to remove the JavaScript link.
+        Overrides the parent class's method to preserve valid URLs.
 
-        Parameters:
-        -----------
-        link : str
-            The hyperlink (href attribute value) to be checked and potentially sanitized.
+        This method uses a regular expression to identify valid URLs that start with 'http', 'https',
+        'ftp', or 'file' schemes. If the link is a valid URL, it is returned unchanged. Otherwise,
+        the parent class's method is used to remove the JavaScript link.
+
+        Args:
+            link (str): The hyperlink (href attribute value) to be checked and potentially sanitized.
 
         Returns:
-        --------
-        Optional[str]
-            The original link if it is a valid URL; otherwise, the result of the parent class's method
-            to handle the link.
-
-        Example:
-        --------
-        'https://www.example.com/javascript:something'   Valid
-        'javascript:alert("hello")' Invalid
-        'http://example.com/path/to/page'   Valid
-        'ftp://ftp.example.com/resource'   Valid
-        'file://localhost/path/to/file'   Valid
+            str: The original link or empty string.
+
+        Examples:
+            Valid URLs:
+                'https://www.example.com/javascript:something'
+                'file://localhost/path/to/file'
+            Invalid URLs:
+                'javascript:alert("hello")'
+                'javascript:alert("hello") https://www.example.com/page'
         """
         is_url = re.compile(r"^(?:https?|ftp|file)://", re.I).search(link.strip())
         if is_url:
             return link
-        super()._remove_javascript_link(link)
+        return super()._remove_javascript_link(link)
 
 
 def HTML(html):                                 # pylint: disable=invalid-name

openedx/core/djangolib/tests/test_markup.py

@@ -158,34 +158,32 @@ def test_clean_dengers_html_filter(self):
         assert not html_soup.find('blink')
         assert not html_soup.find('object')
 
-
+@ddt.ddt
 class TestHTMLCleaner(unittest.TestCase):
     """
     Tests that Url links are being cleaned properly and no useful link is removed.
     """
 
     def setUp(self):
-        self.cleaner = HTMLCleaner(style=True, inline_style=False, safe_attrs_only=False)
-
-    def test_valid_urls(self):
-        https_url = "https://example.com"
-        http_url = "http://example.com/path/to/page"
-        ftp_url = "ftp://ftp.example.com/resource"
-        file_url = "file://localhost/path/to/file"
-
-        cleaned_url = self.cleaner._remove_javascript_link(https_url)
-        self.assertEqual(cleaned_url, https_url)
+        self.cleaner = HTMLCleaner()
 
-        cleaned_url = self.cleaner._remove_javascript_link(http_url)
-        self.assertEqual(cleaned_url, http_url)
-
-        cleaned_url = self.cleaner._remove_javascript_link(ftp_url)
-        self.assertEqual(cleaned_url, ftp_url)
-
-        cleaned_url = self.cleaner._remove_javascript_link(file_url)
-        self.assertEqual(cleaned_url, file_url)
+    @ddt.data(
+        "https://example.com/",
+        "http://example.com/path/to/page",
+        "ftp://ftp.example.com/resource",
+        "file://localhost/path/to/file",
+    )
+    def test_valid_urls(self, url):
+        """
+        Test that valid URLs are preserved.
+        """
+        cleaned_url = self.cleaner._remove_javascript_link(url)
+        self.assertEqual(cleaned_url, url)
 
     def test_javascript_link(self):
+        """
+        Test that malicious Javascript is removed.
+        """
         cleaned_url = self.cleaner._remove_javascript_link("javascript:alert('Hello')")
         self.assertIsNone(cleaned_url)