Throw NotImplementedError for HELLO (#1912)

* unsupported hello

* add test and docstring

* linters

* fix docstring

* linters

* linters

Author: dvora-h

redis/commands/core.py

@@ -1087,6 +1087,15 @@ def wait(self, num_replicas, timeout, **kwargs):
         """
         return self.execute_command("WAIT", num_replicas, timeout, **kwargs)
 
+    def hello(self):
+        """
+        This function throws a NotImplementedError since it is intentionally
+        not supported.
+        """
+        raise NotImplementedError(
+            "HELLO is intentionally not implemented in the client."
+        )
+
     def failover(self):
         """
         This function throws a NotImplementedError since it is intentionally

tests/test_commands.py

@@ -624,6 +624,11 @@ def test_client_getredir(self, r):
         assert isinstance(r.client_getredir(), int)
         assert r.client_getredir() == -1
 
+    @skip_if_server_version_lt("6.0.0")
+    def test_hello_notI_implemented(self, r):
+        with pytest.raises(NotImplementedError):
+            r.hello()
+
     def test_config_get(self, r):
         data = r.config_get()
         assert len(data.keys()) > 10