Add decr command

pyredis/commands.py

@@ -70,6 +70,44 @@ def _handle_exists(command, datastore):
         return Error("ERR wrong number of arguments for 'exists' command")
 
 
+def _handle_del(command, datastore):
+    if len(command) >= 2:
+        found = 0
+        for key in command[1:]:
+            if key.data.decode() in datastore:
+                del datastore._data[key.data.decode()]
+                found += 1
+        return Integer(found)
+    else:
+        return Error("ERR wrong number of arguments for 'del' command")
+
+
+def _handle_incr(command, datastore):
+    if len(command) == 2:
+        key = command[1].data.decode()
+        try:
+            value = datastore[key] + 1
+        except KeyError:
+            value = 1  # first time increase
+        datastore[key] = value
+        return Integer(value)
+    return Error("ERR wrong number of arguments for 'incr' command")
+
+
+def _handle_decr(command, datastore):
+    if len(command) == 2:
+        key = command[1].data.decode()
+        try:
+            value = datastore[key] - 1
+        except KeyError:
+            value = -1
+        except TypeError:
+            return Error("value is not an integer or out of range")
+        datastore[key] = value
+        return Integer(value)
+    return Error("ERR wrong number of arguments for 'decr' command")
+
+
 def _handle_unrecognised_command(command, *args):
     args = " ".join((f"'{c.data.decode()}'" for c in command[1:]))
     return Error(
@@ -87,10 +125,14 @@ def handle_command(command, datastore):
 
         case "SET":
             return _handle_set(command, datastore)
-
         case "GET":
             return _handle_get(command, datastore)
         case "EXISTS":
             return _handle_exists(command, datastore)
-
+        case "DEL":
+            return _handle_del(command, datastore)
+        case "INCR":
+            return _handle_incr(command, datastore)
+        case "DECR":
+            return _handle_decr(command, datastore)
     return _handle_unrecognised_command(command)

tests/test_commands.py

@@ -97,6 +97,26 @@ def datastore():
             ),
             Integer(1),
         ),
+        # DEL tests
+        (
+            Array([BulkString(b"SET"), SimpleString(b"key1"), SimpleString(b"Hello")]),
+            SimpleString("OK"),
+        ),
+        (
+            Array([BulkString(b"SET"), SimpleString(b"key2"), SimpleString(b"World")]),
+            SimpleString("OK"),
+        ),
+        (
+            Array(
+                [
+                    BulkString(b"DEL"),
+                    SimpleString(b"key1"),
+                    SimpleString(b"key2"),
+                    SimpleString(b"key3"),
+                ]
+            ),
+            Integer(2),
+        ),
     ],
 )
 def test_handle_command(command, expected, datastore):
@@ -187,3 +207,37 @@ def test_expire_on_read(datastore):
     sleep(0.15)
     with pytest.raises(KeyError):
         datastore["key"]
+
+
+# Incr Tests
+def test_handle_incr_command_valid_key():
+    datastore = DataStore()
+    result = handle_command(
+        Array([BulkString(b"incr"), SimpleString(b"ki")]), datastore
+    )
+    assert result == Integer(1)
+    result = handle_command(
+        Array([BulkString(b"incr"), SimpleString(b"ki")]), datastore
+    )
+    assert result == Integer(2)
+
+
+# Decr Tests
+def test_handle_decr():
+    datastore = DataStore()
+    result = handle_command(
+        Array([BulkString(b"incr"), SimpleString(b"kd")]), datastore
+    )
+    assert result == Integer(1)
+    result = handle_command(
+        Array([BulkString(b"incr"), SimpleString(b"kd")]), datastore
+    )
+    assert result == Integer(2)
+    result = handle_command(
+        Array([BulkString(b"decr"), SimpleString(b"kd")]), datastore
+    )
+    assert result == Integer(1)
+    result = handle_command(
+        Array([BulkString(b"decr"), SimpleString(b"kd")]), datastore
+    )
+    assert result == Integer(0)