Add support for SINTERCARD (#1859)

* add sintercard

* fix pr comment

redis/commands/core.py

@@ -2388,6 +2388,19 @@ def sinter(self, keys, *args):
         args = list_or_args(keys, args)
         return self.execute_command("SINTER", *args)
 
+    def sintercard(self, numkeys: int, keys: List[str], limit: int = 0) -> int:
+        """
+        Return the cardinality of the intersect of multiple sets specified by ``keys`.
+
+        When LIMIT provided (defaults to 0 and means unlimited), if the intersection
+        cardinality reaches limit partway through the computation, the algorithm will
+        exit and yield limit as the cardinality
+
+        For more information check https://redis.io/commands/sintercard
+        """
+        args = [numkeys, *keys, "LIMIT", limit]
+        return self.execute_command("SINTERCARD", *args)
+
     def sinterstore(self, dest, keys, *args):
         """
         Store the intersection of sets specified by ``keys`` into a new

tests/test_commands.py

@@ -1748,6 +1748,15 @@ def test_sinter(self, r):
         r.sadd("b", "2", "3")
         assert r.sinter("a", "b") == {b"2", b"3"}
 
+    @pytest.mark.onlynoncluster
+    # @skip_if_server_version_lt("7.0.0") turn on after redis 7 release
+    def test_sintercard(self, unstable_r):
+        unstable_r.sadd("a", 1, 2, 3)
+        unstable_r.sadd("b", 1, 2, 3)
+        unstable_r.sadd("c", 1, 3, 4)
+        assert unstable_r.sintercard(3, ["a", "b", "c"]) == 2
+        assert unstable_r.sintercard(3, ["a", "b", "c"], limit=1) == 1
+
     @pytest.mark.onlynoncluster
     def test_sinterstore(self, r):
         r.sadd("a", "1", "2", "3")