diff --git a/changelog.d/14981.misc b/changelog.d/14981.misc
new file mode 100644
index 0000000000..68ac8335fc
--- /dev/null
+++ b/changelog.d/14981.misc
@@ -0,0 +1 @@
+Add tests for `_flatten_dict`.
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index 9bf92b9765..20369f3dfe 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -473,6 +473,29 @@ def _flatten_dict(
prefix: Optional[List[str]] = None,
result: Optional[Dict[str, str]] = None,
) -> Dict[str, str]:
+ """
+ Given a JSON dictionary (or event) which might contain sub dictionaries,
+ flatten it into a single layer dictionary by combining the keys & sub-keys.
+
+ Any (non-dictionary), non-string value is dropped.
+
+ Transforms:
+
+ {"foo": {"bar": "test"}}
+
+ To:
+
+ {"foo.bar": "test"}
+
+ Args:
+ d: The event or content to continue flattening.
+ room_version: The room version object.
+ prefix: The key prefix (from outer dictionaries).
+ result: The result to mutate.
+
+ Returns:
+ The resulting dictionary.
+ """
if prefix is None:
prefix = []
if result is None:
diff --git a/tests/push/test_push_rule_evaluator.py b/tests/push/test_push_rule_evaluator.py
index 81661e181b..7c430c4ecb 100644
--- a/tests/push/test_push_rule_evaluator.py
+++ b/tests/push/test_push_rule_evaluator.py
@@ -12,7 +12,7 @@
# See the License for the specific language governing permissions and
# limitations under the License.
-from typing import Dict, List, Optional, Set, Union, cast
+from typing import Any, Dict, List, Optional, Set, Union, cast
import frozendict
@@ -37,6 +37,30 @@ from tests import unittest
from tests.test_utils.event_injection import create_event, inject_member_event
+class FlattenDictTestCase(unittest.TestCase):
+ def test_simple(self) -> None:
+ """Test a dictionary that isn't modified."""
+ input = {"foo": "abc"}
+ self.assertEqual(input, _flatten_dict(input))
+
+ def test_nested(self) -> None:
+ """Nested dictionaries become dotted paths."""
+ input = {"foo": {"bar": "abc"}}
+ self.assertEqual({"foo.bar": "abc"}, _flatten_dict(input))
+
+ def test_non_string(self) -> None:
+ """Non-string items are dropped."""
+ input: Dict[str, Any] = {
+ "woo": "woo",
+ "foo": True,
+ "bar": 1,
+ "baz": None,
+ "fuzz": [],
+ "boo": {},
+ }
+ self.assertEqual({"woo": "woo"}, _flatten_dict(input))
+
+
class PushRuleEvaluatorTestCase(unittest.TestCase):
def _get_evaluator(
self,
|
