# Chapter 8 unittest framework
import unittest # standard module

# Tests at the class level
# requires a class to be defined

class MathFunctionsTestCase(unittest.TestCase):

    #Define test method starting with word "test"
    def test_addition(self):
        result = 2 + 3  # 5
        self.assertEqual(result, 5)

    def test_subtraction(self):
        result = 2 - 3  # -1
        self.assertEqual(result, -1)

    def test_multiplication(self):
        result = 2 * 3  # 6
        self.assertEqual(result, 6)

    def test_division(self):
        result = 2 / 3  # .6666666in
        self.assertAlmostEqual(result, .6666)

# run the tests
if __name__ == "__main__":
    class CustomTestResult(unittest.TextTestResult):
         # On init function to create 3 params for log file

        def __init__(self, stream, descriptions, verbosity):
            super().__init__(stream, descriptions, verbosity)
            self.logfile = open("test_log.txt", "w")

        # Create all the result fixtures success, fail, error
        def addSuccess(self, test):
            super().addSuccess(test)
            self.logfile.write(f"SUCCESS: {test}\n") # string stream
            self.logfile.write(f" ---- \n")

        def addFailure(self, test, err):
            super().addFailure(test,err)
            self.logfile.write(f"FAILURE: {test} \n") # string stream
            self.logfile.write(f"FAILURE ERROR: {err} \n")
            self.logfile.write(f" ---- \n")

        def addError(self, test, err):
            super().addError(test,err)
            self.logfile.write(f"EXCEPTION ERROR: {test} \n") # string stream
            self.logfile.write(f"ERROR CODE: {err} \n")
            self.logfile.write(f" ---- \n")

        def stopTestRun(self):
            super().stopTestRun()
            self.logfile.close() # close the log file manually

    # execute the tests and log ALL results
    suite = unittest.TestLoader().loadTestsFromTestCase(MathFunctionsTestCase)

    # capture the execute to the custom class
    runner = unittest.TextTestRunner(resultclass=CustomTestResult)
    runner.run(suite)