1 files changed, 84 insertions, 0 deletions
diff --git a/tests/storage/test_event_metrics.py b/tests/storage/test_event_metrics.py
new file mode 100644
index 0000000000..d44359ff93
--- /dev/null
+++ b/tests/storage/test_event_metrics.py
@@ -0,0 +1,84 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the 'License');
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an 'AS IS' BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from prometheus_client.exposition import generate_latest
+
+from synapse.metrics import REGISTRY
+from synapse.types import Requester, UserID
+
+from tests.unittest import HomeserverTestCase
+
+
+class ExtremStatisticsTestCase(HomeserverTestCase):
+    def test_exposed_to_prometheus(self):
+        """
+        Forward extremity counts are exposed via Prometheus.
+        """
+        room_creator = self.hs.get_room_creation_handler()
+
+        user = UserID("alice", "test")
+        requester = Requester(user, None, False, None, None)
+
+        # Real events, forward extremities
+        events = [(3, 2), (6, 2), (4, 6)]
+
+        for event_count, extrems in events:
+            info = self.get_success(room_creator.create_room(requester, {}))
+            room_id = info["room_id"]
+
+            last_event = None
+
+            # Make a real event chain
+            for i in range(event_count):
+                ev = self.create_and_send_event(room_id, user, False, last_event)
+                last_event = [ev]
+
+            # Sprinkle in some extremities
+            for i in range(extrems):
+                ev = self.create_and_send_event(room_id, user, False, last_event)
+
+        # Let it run for a while, then pull out the statistics from the
+        # Prometheus client registry
+        self.reactor.advance(60 * 60 * 1000)
+        self.pump(1)
+
+        items = set(
+            filter(
+                lambda x: b"synapse_forward_extremities_" in x,
+                generate_latest(REGISTRY).split(b"\n"),
+            )
+        )
+
+        expected = set(
+            [
+                b'synapse_forward_extremities_bucket{le="1.0"} 0.0',
+                b'synapse_forward_extremities_bucket{le="2.0"} 2.0',
+                b'synapse_forward_extremities_bucket{le="3.0"} 2.0',
+                b'synapse_forward_extremities_bucket{le="5.0"} 2.0',
+                b'synapse_forward_extremities_bucket{le="7.0"} 3.0',
+                b'synapse_forward_extremities_bucket{le="10.0"} 3.0',
+                b'synapse_forward_extremities_bucket{le="15.0"} 3.0',
+                b'synapse_forward_extremities_bucket{le="20.0"} 3.0',
+                b'synapse_forward_extremities_bucket{le="50.0"} 3.0',
+                b'synapse_forward_extremities_bucket{le="100.0"} 3.0',
+                b'synapse_forward_extremities_bucket{le="200.0"} 3.0',
+                b'synapse_forward_extremities_bucket{le="500.0"} 3.0',
+                b'synapse_forward_extremities_bucket{le="+Inf"} 3.0',
+                b"synapse_forward_extremities_count 3.0",
+                b"synapse_forward_extremities_sum 10.0",
+            ]
+        )
+
+        self.assertEqual(items, expected)