Adds unit tests that checks if rel field is set on links

bookwyrm/tests/validate_html.py

@@ -1,4 +1,5 @@
 """ html validation on rendered templates """
+from html.parser import HTMLParser
 from tidylib import tidy_document
 
 
@@ -23,3 +24,33 @@ def validate_html(html):
     )
     if errors:
         raise Exception(errors)
+
+    validator = HtmlValidator()
+    # will raise exceptions
+    validator.feed(str(html.content))
+    raise Exception()
+
+
+class HtmlValidator(HTMLParser):  # pylint: disable=abstract-method
+    """Checks for custom html validation requirements"""
+
+    def __init__(self):
+        HTMLParser.__init__(self)
+
+    def handle_starttag(self, tag, attrs):
+        """check if the tag is valid"""
+        # filter out everything besides links that open in new tabs
+        if tag != "a" or ("target", "_blank") not in attrs:
+            return
+
+        for attr, value in attrs:
+            if (
+                attr == "rel"
+                and "nofollow" in value
+                and "noopener" in value
+                and "noreferrer" in value
+            ):
+                return
+        raise Exception(
+            'Links to a new tab must have rel="nofollow noopener noreferrer"'
+        )

bookwyrm/tests/views/landing/test_landing.py

@@ -13,7 +13,7 @@ from bookwyrm.tests.validate_html import validate_html
 class LandingViews(TestCase):
     """pages you land on without really trying"""
 
-    def setUp(self):
+    def setUp(self):  # pylint: disable=invalid-name
         """we need basic test data and mocks"""
         self.factory = RequestFactory()
         with patch("bookwyrm.suggested_users.rerank_suggestions_task.delay"), patch(