Assertion Check

checker.py

#!/usr/bin/env python3

import sys, logging
class FailedValidationException(Exception):
    pass

class ClassToValidate(object):
    def assert__testing_external(self):
        return True

    def assert__should_failed(self):
        raise FailedValidationException("Failed external check")

class ClassWithAssertionChecks(object):
    ''' implements an assertion checker loop '''
    def __init__(self, obj=None, log=None):
        self.passed_assertions = []
        self.failed_assertions = []

        self.obj = obj if obj else self
        self.passed_all_checks = False

        self.log = log
        if not self.log:
            logging.basicConfig(stream=sys.stdout, level=logging.DEBUG)
            self.log = logging.getLogger('AssertionChecker')
        import pdb; pdb.set_trace()
        self.log.info("initializing assertion checker for {}".format(self.obj.__class__.__name__))


    def collect_assertion_checks(self):
        ''' collect assertion check functions '''
        return [func for func in dir(self.obj.__class__) if callable(getattr(self.obj.__class__, func)) and func.startswith("assert__")]

    def check_assertions(self):
        ''' perform assertion check '''
        self.passed_assertions.clear()
        self.failed_assertions.clear()
        for idx, check in enumerate(self.collect_assertion_checks()):
            ''' try to run each test, catch errors  '''
            check_passed = False

            self.log.info("Running check {}: {} ...".format(idx, check))

            try:
                getattr(self.obj.__class__, check)(self)
            except AssertionError as e:
                self.log.error("Assertion caught while checking {}".format(check), exc_info=True)
                self.failed_assertions.append((check, e))
            except Exception as e:
                self.log.error("Exception caught while checking {}".format(check), exc_info=True)
                self.failed_assertions.append((check, e))
            else:
                check_passed = True
                self.passed_assertions.append(check)
            finally:
                self.log.info("Check {}: {} {}".format(idx, check, "passed" if check_passed else "failed"))

        num_passed = len(self.passed_assertions)
        num_failed = len(self.failed_assertions)
        num_checks = num_passed + num_failed

        self.log.info("{} of {} assertion checks passed.".format(num_passed, num_checks))
        self.log.warn("{} of {} assertion checks failed.".format(num_failed, num_checks))

        self.passed_all_checks = num_failed == 0

        return self.passed_all_checks

    def assert__values_equal(self):
        if 1234 == 1234:
            return True

        raise FailedValidationException("Failed equality check")

    def assert__values_equal_fail(self):
        if 1234 == 1235:
            return True

        raise FailedValidationException("Failed equality check")

    def assert_num_rows_greater_than_zero(self):
        num_rows = 1
        if num_rows > 0:
            return True

        raise FailedValidationException("Failed number of rows check")

if __name__=="__main__":
    result = ClassWithAssertionChecks().check_assertions()
    print("\nDone.\nResult = {}".format("Passed" if result else "Failed"))

    result = ClassWithAssertionChecks(ClassToValidate()).check_assertions()
    print("\nDone.\nResult = {}".format("Passed" if result else "Failed"))