python_examples: Use ensure_users where appropriate.

We added this function in 8e1a7cfb52
in order to make things more readable in example which hard-code user
ids. The point is to validate that the id indeed refers to the user that
the person writing the example expects, while providing information to
readers of the code so they don't have to do db queries to figure out
the user. As mentioned in the commit referred to above, this is
particularly useful when some db changes cause renumbering of user ids -
because then all these ids have to be adjusted and it's nice to know the
intended user.

zerver/openapi/python_examples.py

@@ -81,6 +81,7 @@ def add_subscriptions(client: Client) -> None:
 
     validate_against_openapi_schema(result, "/users/me/subscriptions", "post", "200_0")
 
+    ensure_users([26], ["newbie"])
     # {code_example|start}
     # To subscribe other users to a stream, you may pass
     # the `principals` argument, like so:
@@ -238,6 +239,7 @@ def get_user_by_email(client: Client) -> None:
 
 @openapi_test_function("/users/{user_id}:get")
 def get_single_user(client: Client) -> None:
+    ensure_users([8], ["cordelia"])
 
     # {code_example|start}
     # Fetch details on a user given a user ID
@@ -255,6 +257,7 @@ def get_single_user(client: Client) -> None:
 
 @openapi_test_function("/users/{user_id}:delete")
 def deactivate_user(client: Client) -> None:
+    ensure_users([8], ["cordelia"])
 
     # {code_example|start}
     # Deactivate a user
@@ -276,6 +279,7 @@ def reactivate_user(client: Client) -> None:
 
 @openapi_test_function("/users/{user_id}:patch")
 def update_user(client: Client) -> None:
+    ensure_users([8, 10], ["cordelia", "hamlet"])
 
     # {code_example|start}
     # Change a user's full name.
@@ -294,6 +298,8 @@ def update_user(client: Client) -> None:
 
 @openapi_test_function("/users/{user_id}/subscriptions/{stream_id}:get")
 def get_subscription_status(client: Client) -> None:
+    ensure_users([7], ["zoe"])
+
     # {code_example|start}
     # Check whether a user is a subscriber to a given stream.
     user_id = 7