tests: detect issues with our HTML

pyproject.toml

@@ -36,6 +36,7 @@ python_files = ["tests*.py", "test_*.py"]
 filterwarnings = [
     "error",
     "ignore:.*Use timezone-aware objects to represent datetimes in UTC.*:DeprecationWarning:(botocore|django_datadog_logger)",
+    "ignore:.*The 'strip_cdata' option of HTMLParser\\(\\) has never done anything and will eventually be removed.",
 ]
 addopts = [
     "--reuse-db",

tests/utils/test.py

@@ -126,6 +126,26 @@ def request(self, **request):
             # Detect rendering issues in templates
             assert "{{" not in content
             assert "{%" not in content
+
+            if request.get("HTTP_HX_REQUEST") != "true":  # Do not check htmx requests that contain partial documents
+                # Check HTML consistency (use lxml parser for speed)
+                soup = BeautifulSoup(content, "lxml")
+
+                tag_with_ids = soup.find_all(id=True)
+                ids = {tag.attrs["id"] for tag in tag_with_ids}
+                # Check for for duplicate ids
+                assert len(ids) == len(tag_with_ids)
+
+                for tag in soup.find_all(attrs={"aria-labelledby": True}):
+                    assert tag.attrs["aria-labelledby"] in ids
+
+                for tag in soup.find_all(attrs={"aria-controls": True}):
+                    assert tag.attrs["aria-controls"] in ids
+
+                for tag in soup.find_all(attrs={"data-bs-target": True}):
+                    if tag.attrs["data-bs-target"][0] == "#":
+                        assert tag.attrs["data-bs-target"][1:] in ids
+
         return response