PuppyParachute

Goals

See example runtime values side-by-side with the code.

Annotations can easily be generated from existing unittests using a nosetests plugin:

> nosetests3 demo --puppy-package app --puppy-annotate

This will annotate all functions covered by the tests, including example inputs and outputs, for instance:

#? what=that -> Done
def do_things(what):
    print('Doing {}'.format(what))
    return 'Done'

This also works for methods with side-effects:

class A(object):
    #? i=2, self=A {n: 10} -> None | self=A {n: 12}
    def inc(self, i):
        self.n += i

The #?-annotations can be removed using the deannotate script.

See the effects of a change in all parts of the code.

Inspect changes and accept them by simply copying a file.

Track behavior changes in version control along with code changes.

See an example code change, and the associated change at runtime in this commit.

Achieve very high code coverage with few tests and no code change.

Deal with under-tested project, difficult to isolate code, and tough deadlines.

Specify one or more entry-points or test cases to run the code. Entry-points can be more or less high-level.
While running the code, PuppyParachute records every function call, with parameters, relevant environment, behavior, and return values.
Compare differences in outputs and behavior of the whole code with previous run.
Check in and track the record as a text/YAML file in version control.