Add tests for HTML sanitization contexts

tildes/tests/test_markdown.py

@@ -3,6 +3,7 @@
 
 from bs4 import BeautifulSoup
 
+from tildes.enums import BleachContext
 from tildes.lib.markdown import convert_markdown_to_safe_html
 
 
@@ -389,3 +390,19 @@ def test_image_syntax_ignored():
 
     assert "!<a" in processed
     assert "img" not in processed
+
+
+def test_a_rel_removed_default_context():
+    """Ensure a rel= attr is removed from an <a> tag by default."""
+    markdown = '<a href="http://example.com" rel="something">Link</a>'
+    processed = convert_markdown_to_safe_html(markdown)
+
+    assert "rel=" not in processed
+
+
+def test_a_rel_kept_user_bio_context():
+    """Ensure a rel= attr is kept on an <a> tag in the user bio context."""
+    markdown = '<a href="http://example.com" rel="something">Link</a>'
+    processed = convert_markdown_to_safe_html(markdown, BleachContext.USER_BIO)
+
+    assert "rel=" in processed