Merge remote-tracking branch 'origin/release-v1.27.0' into bbz/info-mainline-1.27.0 github/bbz/info-mainline-1.27.0 bbz/info-mainline-1.27.0

2 files changed, 110 insertions, 24 deletions

diff --git a/tests/util/caches/test_deferred_cache.py b/tests/util/caches/test_deferred_cache.py
index dadfabd46d..ecd9efc4df 100644
--- a/tests/util/caches/test_deferred_cache.py
+++ b/tests/util/caches/test_deferred_cache.py
@@ -25,13 +25,8 @@ from tests.unittest import TestCase
 class DeferredCacheTestCase(TestCase):
     def test_empty(self):
         cache = DeferredCache("test")
-        failed = False
-        try:
+        with self.assertRaises(KeyError):
             cache.get("foo")
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
 
     def test_hit(self):
         cache = DeferredCache("test")
@@ -155,13 +150,8 @@ class DeferredCacheTestCase(TestCase):
         cache.prefill(("foo",), 123)
         cache.invalidate(("foo",))
 
-        failed = False
-        try:
+        with self.assertRaises(KeyError):
             cache.get(("foo",))
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
 
     def test_invalidate_all(self):
         cache = DeferredCache("testcache")
@@ -215,13 +205,8 @@ class DeferredCacheTestCase(TestCase):
         cache.prefill(2, "two")
         cache.prefill(3, "three")  # 1 will be evicted
 
-        failed = False
-        try:
+        with self.assertRaises(KeyError):
             cache.get(1)
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
 
         cache.get(2)
         cache.get(3)
@@ -239,13 +224,55 @@ class DeferredCacheTestCase(TestCase):
 
         cache.prefill(3, "three")
 
-        failed = False
-        try:
+        with self.assertRaises(KeyError):
             cache.get(2)
-        except KeyError:
-            failed = True
 
-        self.assertTrue(failed)
+        cache.get(1)
+        cache.get(3)
+
+    def test_eviction_iterable(self):
+        cache = DeferredCache(
+            "test", max_entries=3, apply_cache_factor_from_config=False, iterable=True,
+        )
+
+        cache.prefill(1, ["one", "two"])
+        cache.prefill(2, ["three"])
 
+        # Now access 1 again, thus causing 2 to be least-recently used
+        cache.get(1)
+
+        # Now add an item to the cache, which evicts 2.
+        cache.prefill(3, ["four"])
+        with self.assertRaises(KeyError):
+            cache.get(2)
+
+        # Ensure 1 & 3 are in the cache.
         cache.get(1)
         cache.get(3)
+
+        # Now access 1 again, thus causing 3 to be least-recently used
+        cache.get(1)
+
+        # Now add an item with multiple elements to the cache
+        cache.prefill(4, ["five", "six"])
+
+        # Both 1 and 3 are evicted since there's too many elements.
+        with self.assertRaises(KeyError):
+            cache.get(1)
+        with self.assertRaises(KeyError):
+            cache.get(3)
+
+        # Now add another item to fill the cache again.
+        cache.prefill(5, ["seven"])
+
+        # Now access 4, thus causing 5 to be least-recently used
+        cache.get(4)
+
+        # Add an empty item.
+        cache.prefill(6, [])
+
+        # 5 gets evicted and replaced since an empty element counts as an item.
+        with self.assertRaises(KeyError):
+            cache.get(5)
+        cache.get(4)
+        cache.get(6)
diff --git a/tests/util/test_itertools.py b/tests/util/test_itertools.py
index 0ab0a91483..1ef0af8e8f 100644
--- a/tests/util/test_itertools.py
+++ b/tests/util/test_itertools.py
@@ -12,7 +12,9 @@
 # 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 synapse.util.iterutils import chunk_seq
+from typing import Dict, List
+
+from synapse.util.iterutils import chunk_seq, sorted_topologically
 
 from tests.unittest import TestCase
 
@@ -45,3 +47,60 @@ class ChunkSeqTests(TestCase):
         self.assertEqual(
             list(parts), [],
         )
+
+
+class SortTopologically(TestCase):
+    def test_empty(self):
+        "Test that an empty graph works correctly"
+
+        graph = {}  # type: Dict[int, List[int]]
+        self.assertEqual(list(sorted_topologically([], graph)), [])
+
+    def test_handle_empty_graph(self):
+        "Test that a graph where a node doesn't have an entry is treated as empty"
+
+        graph = {}  # type: Dict[int, List[int]]
+
+        # For disconnected nodes the output is simply sorted.
+        self.assertEqual(list(sorted_topologically([1, 2], graph)), [1, 2])
+
+    def test_disconnected(self):
+        "Test that a graph with no edges work"
+
+        graph = {1: [], 2: []}  # type: Dict[int, List[int]]
+
+        # For disconnected nodes the output is simply sorted.
+        self.assertEqual(list(sorted_topologically([1, 2], graph)), [1, 2])
+
+    def test_linear(self):
+        "Test that a simple `4 -> 3 -> 2 -> 1` graph works"
+
+        graph = {1: [], 2: [1], 3: [2], 4: [3]}  # type: Dict[int, List[int]]
+
+        self.assertEqual(list(sorted_topologically([4, 3, 2, 1], graph)), [1, 2, 3, 4])
+
+    def test_subset(self):
+        "Test that only sorting a subset of the graph works"
+        graph = {1: [], 2: [1], 3: [2], 4: [3]}  # type: Dict[int, List[int]]
+
+        self.assertEqual(list(sorted_topologically([4, 3], graph)), [3, 4])
+
+    def test_fork(self):
+        "Test that a forked graph works"
+        graph = {1: [], 2: [1], 3: [1], 4: [2, 3]}  # type: Dict[int, List[int]]
+
+        # Valid orderings are `[1, 3, 2, 4]` or `[1, 2, 3, 4]`, but we should
+        # always get the same one.
+        self.assertEqual(list(sorted_topologically([4, 3, 2, 1], graph)), [1, 2, 3, 4])
+
+    def test_duplicates(self):
+        "Test that a graph with duplicate edges work"
+        graph = {1: [], 2: [1, 1], 3: [2, 2], 4: [3]}  # type: Dict[int, List[int]]
+
+        self.assertEqual(list(sorted_topologically([4, 3, 2, 1], graph)), [1, 2, 3, 4])
+
+    def test_multiple_paths(self):
+        "Test that a graph with multiple paths between two nodes work"
+        graph = {1: [], 2: [1], 3: [2], 4: [3, 2, 1]}  # type: Dict[int, List[int]]
+
+        self.assertEqual(list(sorted_topologically([4, 3, 2, 1], graph)), [1, 2, 3, 4])