run tests and get coverage report

with_coverage.py

import coverage


class coverall(object):
    def __enter__(self):
        self.coverage = coverage.coverage()
        self.coverage.erase()
        self.coverage.start()

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.coverage.stop()
        self.coverage.save()
        self.coverage.report()


with coverall():
    # ...
    # run tests
    sys.exit(1)