Generators

In addition to returning values and raising exceptions, flexmock can also turn the mocked method into a generator that yields successive values:

>>> flexmock(plane).should_receive("flight_log").and_yield(
    "take off", "flight", "landing")
>>> for i in plane.flight_log():
>>>     print(i)
"take off"
"flight"
"landing"

You can also use Python's builtin iter() function to generate an iterable return value:

flexmock(plane, flight_log=iter(["take off", "flight", "landing"]))

In fact, the and_yield() modifier is just shorthand for should_receive().and_return(iter) under the hood.