Spying

In addition to stubbing out a given method and returning fake values, flexmock also allows you to call the original method and make expectations based on its return values/exceptions and the number of times the method is called with the given arguments.

Note

should_call() changes the behavior of and_return() and and_raise() to specify expectations rather than generate given values or exceptions.

Matching specific arguments:

flexmock(plane).should_call("repair").with_args("wing", "cockpit").once()

Matching any arguments:

flexmock(plane).should_call("turn").twice()

Matching specific return values:

flexmock(plane).should_call("land").and_return("landed!")

Matching a regular expression:

flexmock(plane).should_call("land").and_return(re.compile("^la"))

Match return values by class/type:

flexmock(plane).should_call("fly").and_return(str, object, None)

Ensure that an appropriate exception is raised:

flexmock(plane).should_call("fly").and_raise(BadWeatherException)

Check that the exception message matches your expectations:

flexmock(plane).should_call("fly").and_raise(
    BadWeatherException, "Oh noes, rain!"
)

Check that the exception message matches a regular expression:

flexmock(plane).should_call("fly").and_raise(
    BadWeatherException, re.compile("rain")
)

If either and_return() or and_raise() is provided, flexmock will verify that the return value matches the expected return value or exception.