---

---

---

test elevator with list comprehensions

I want to use for loops in the Elevator project. It has tests for an Elevator Controller that will MOVE the Elevator Car to a floor when I push a button for the floor based on these inputs:

• was the number for a floor pushed?

• are the doors closed?

• is it above the weight limit?

• was the emergency button pushed?

the inputs gave me this truth table

floor button	doors	weight limit	emergency button	output
pushed	closed	above	pushed	False
pushed	closed	above	NOT pushed	False
pushed	closed	below	pushed	False
pushed	closed	below	NOT pushed	True

floor button	doors	weight limit	emergency button	output
pushed	open	above	pushed	False
pushed	open	above	NOT pushed	False
pushed	open	below	pushed	False
pushed	open	below	NOT pushed	False

floor button	doors	weight limit	emergency button	output
NOT pushed	closed	above	pushed	False
NOT pushed	closed	above	NOT pushed	False
NOT pushed	closed	below	pushed	False
NOT pushed	closed	below	NOT pushed	False

floor button	doors	weight limit	emergency button	output
NOT pushed	open	above	pushed	False
NOT pushed	open	above	NOT pushed	False
NOT pushed	open	below	pushed	False
NOT pushed	open	below	NOT pushed	False

The only time this elevator moves up or down is when the button for a floor is pushed AND the doors are closed AND the Elevator is NOT above the weight limit, and the emergency button is NOT pushed.

preview

These is the test I have at the end of the chapter

elevator/tests/test_elevator.py

import src.elevator
import unittest


class TestElevator(unittest.TestCase):

    def test_elevator_controller(self):
        booleans = (False, True)
        for number_pushed in booleans:
            for doors_closed in booleans:
                for above_weight in booleans:
                    for emergency in booleans:
                        with self.subTest(
                            number_pushed=number_pushed,
                            doors_closed=doors_closed,
                            above_weight=above_weight,
                            emergency=emergency,
                        ):
                            result = src.elevator.controller(
                                number_pushed=number_pushed,
                                doors_closed=doors_closed,
                                above_weight=above_weight,
                                emergency=emergency,
                            )
                            try:
                                self.assertFalse(result)
                            except AssertionError:
                                self.assertTrue(result)


# Exceptions seen
# AssertionError
# NameError
# AttributeError
# TypeError
# SyntaxError

---

open the project

• I open a terminal

• I change directory to the elevator folder in the pumping_python folder

• I open test_elevator.py from the tests folder

• I use pytest-watcher to run the tests automatically

  terminal

  uv run pytest-watcher . --now
  

---

extract test_elevator_controller

RED: make it fail

---

I add a test with a for loop for all the cases

elevator/tests/test_elevator.py

class TestElevator(unittest.TestCase):

    def test_elevator_controller(self):
        booleans = (False, True)
        for number_pushed in booleans:
            for doors_closed in booleans:
                for above_weight in booleans:
                    for emergency in booleans:
                        with self.subTest(
                            number_pushed=number_pushed,
                            doors_closed=doors_closed,
                            above_weight=above_weight,
                            emergency=emergency,
                        ):

elevator/tests/test_elevator.py

                            result = src.elevator.controller(
                                number_pushed=number_pushed,
                                doors_closed=doors_closed,
                                above_weight=above_weight,
                                emergency=emergency,
                            )
                            self.assertEqual(result, 'BOOM!!!')

    def test_above_weight_doors_closed_number_pushed(self):

the terminal is my friend, and shows AssertionError

terminal

SUBFAILED(
    number_pushed=False, doors_closed=False,
    above_weight=False, emergency=False
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=False, doors_closed=False,
    above_weight=False, emergency=True
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=False, doors_closed=False,
    above_weight=True, emergency=False
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=False, doors_closed=False,
    above_weight=True, emergency=True
) ... AssertionError: False != 'BOOM!!!'

terminal

SUBFAILED(
    number_pushed=False, doors_closed=True,
    above_weight=False, emergency=False
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=False, doors_closed=True,
    above_weight=False, emergency=True
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=False, doors_closed=True,
    above_weight=True, emergency=False
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=False, doors_closed=True,
    above_weight=True, emergency=True
) ... AssertionError: False != 'BOOM!!!'

terminal

SUBFAILED(
    number_pushed=True, doors_closed=False,
    above_weight=False, emergency=False
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=True, doors_closed=False,
    above_weight=False, emergency=True
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=True, doors_closed=False,
    above_weight=True, emergency=False
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=True, doors_closed=False,
    above_weight=True, emergency=True
) ... AssertionError: False != 'BOOM!!!'

terminal

SUBFAILED(
    number_pushed=True, doors_closed=True,
    above_weight=False, emergency=False
) ... AssertionError: True != 'BOOM!!!'
SUBFAILED(
    number_pushed=True, doors_closed=True,
    above_weight=False, emergency=True
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=True, doors_closed=True,
    above_weight=True, emergency=False
) ... AssertionError: False != 'BOOM!!!'
SUBFAILED(
    number_pushed=True, doors_closed=True,
    above_weight=True, emergency=True
) ... AssertionError: False != 'BOOM!!!'

---

GREEN: make it pass

---

• I change self.assertEqual(result, 'BOOM!!!') to handle the fifteen cases where the controller functions returns False

  elevator/tests/test_elevator.py

                              result = src.elevator.controller(
                                  number_pushed=number_pushed,
                                  doors_closed=doors_closed,
                                  above_weight=above_weight,
                                  emergency=emergency,
                              )
                              self.assertFalse(result)
  
      def test_above_weight_doors_closed_number_pushed(self):
  

  the terminal is my friend, and shows AssertionError

  terminal

  SUBFAILED(
      number_pushed=True, doors_closed=True,
      above_weight=False, emergency=False
  ) ... AssertionError: True is not false
  

• I move the assertion into a try statement for it

  elevator/tests/test_elevator.py

                            result = src.elevator.controller(
                                number_pushed=number_pushed,
                                doors_closed=doors_closed,
                                above_weight=above_weight,
                                emergency=emergency,
                            )
                            try:
                                self.assertFalse(result)
                            except AssertionError:
                                self.assertTrue(result)
  
    def test_above_weight_doors_closed_number_pushed(self):
  

  the test passes.

---

REFACTOR: make it better

---

• I remove all the other tests because they are now covered by test_elevator_controller

  elevator/tests/test_elevator.py

                              try:
                                  self.assertFalse(result)
                              except AssertionError:
                                  self.assertTrue(result)
  
  
  # Exceptions seen
  

• I add a git commit message

  terminal

  git commit -am \
  'extract test_elevator_controller'
  

---

close the project

• I close tests/test_elevator.py

• I click in the terminal where the tests are running

• I use q on the keyboard to leave the tests

• I change directory to the parent of Elevator

  terminal

  cd ..
  

---

review

I also used four nested for loops to make one test for all sixteen cases. There has to be a better way that looks better.

---

code from the chapter

Do you want to see all the CODE I typed in this chapter?

---

what is next?

• I know how to make a Python Test Driven Development environment manually.

• I know what a Python module is.

• I know how to run tests automatically.

• I know what an assertion is.

• I know how to make functions.

• I know how to make a person with strings.

• I know how to make functions that take input.

• I know what causes TypeError.

• I know how to place values in strings.

• I know how to make a person say hello with f-strings.

• I know how to separate tests from solutions.

• I know what causes AttributeError.

• I know how to make a person with an object.

• I know that everything in Python is an object.

• I know how to use the unittest library.

• I know how to use the datetime library.

• I know what None is.

• I know how to make a person with conditions.

• I know how Python groups objects into False or True.

• I know how to make a Python Test Driven Development environment automatically.

• I know how to write programs that make decisions.

• I know how to make a Python Test Driven Development environment automatically with variables.

• I know how to make a person with Exceptions.

• I know how to test that an Exception is raised.

• I know how to use Exception handlers in programs.

• I know how to make a person with loops.

Would you like to test the functions project with loops?

---

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