Add support to BF.CARD (#2545)

* Add support to BF.CARD

* Add Async test

* change to with pytest.raises

redis/commands/bf/__init__.py

@@ -198,6 +198,7 @@ def __init__(self, client, **kwargs):
             # BF_MEXISTS: spaceHolder,
             # BF_SCANDUMP: spaceHolder,
             # BF_LOADCHUNK: spaceHolder,
+            # BF_CARD: spaceHolder,
             BF_INFO: BFInfo,
         }
 

redis/commands/bf/commands.py

@@ -11,6 +11,7 @@
 BF_SCANDUMP = "BF.SCANDUMP"
 BF_LOADCHUNK = "BF.LOADCHUNK"
 BF_INFO = "BF.INFO"
+BF_CARD = "BF.CARD"
 
 CF_RESERVE = "CF.RESERVE"
 CF_ADD = "CF.ADD"
@@ -165,6 +166,14 @@ def info(self, key):
         """  # noqa
         return self.execute_command(BF_INFO, key)
 
+    def card(self, key):
+        """
+        Returns the cardinality of a Bloom filter - number of items that were added to a Bloom filter and detected as unique
+        (items that caused at least one bit to be set in at least one sub-filter).
+        For more information see `BF.CARD <https://redis.io/commands/bf.card>`_.
+        """  # noqa
+        return self.execute_command(BF_CARD, key)
+
 
 class CFCommands:
     """Cuckoo Filter commands."""

tests/test_asyncio/test_bloom.py

@@ -149,6 +149,21 @@ async def test_bf_info(modclient: redis.Redis):
         assert True
 
 
+@pytest.mark.redismod
+async def test_bf_card(modclient: redis.Redis):
+    # return 0 if the key does not exist
+    assert await modclient.bf().card("not_exist") == 0
+
+    # Store a filter
+    assert await modclient.bf().add("bf1", "item_foo") == 1
+    assert await modclient.bf().card("bf1") == 1
+
+    # Error when key is of a type other than Bloom filter.
+    with pytest.raises(redis.ResponseError):
+        await modclient.set("setKey", "value")
+        await modclient.bf().card("setKey")
+
+
 # region Test Cuckoo Filter
 @pytest.mark.redismod
 async def test_cf_add_and_insert(modclient: redis.Redis):

tests/test_bloom.py

@@ -165,6 +165,21 @@ def test_bf_info(client):
         assert True
 
 
+@pytest.mark.redismod
+def test_bf_card(client):
+    # return 0 if the key does not exist
+    assert client.bf().card("not_exist") == 0
+
+    # Store a filter
+    assert client.bf().add("bf1", "item_foo") == 1
+    assert client.bf().card("bf1") == 1
+
+    # Error when key is of a type other than Bloom filter.
+    with pytest.raises(redis.ResponseError):
+        client.set("setKey", "value")
+        client.bf().card("setKey")
+
+
 # region Test Cuckoo Filter
 @pytest.mark.redismod
 def test_cf_add_and_insert(client):