Tests that got me a job 😎

test_payment_processor.py

'''Test for Payment Processor.
Author: Animesh Ghosh
'''
import unittest
from unittest.mock import patch
from io import StringIO
from payment_processor import PaymentProcessor


class TestPaymentProcessor(unittest.TestCase):
    def setUp(self):
        self.payment_processor = PaymentProcessor()

    def test_add_item_to_process_invalid_type(self):
        self.assertRaises(TypeError, self.payment_processor.add_item_to_process, True)
        self.assertRaises(TypeError, self.payment_processor.add_item_to_process, 3.14)
        self.assertRaises(TypeError, self.payment_processor.add_item_to_process, 42)

    def test_add_item_to_process_unsupported_item(self):
        self.assertRaises(
            ValueError, self.payment_processor.add_item_to_process, 'oven'
        )
        self.assertRaises(
            ValueError, self.payment_processor.add_item_to_process, 'fridge'
        )

    @patch('sys.stdout', new_callable=StringIO)
    def test_process_items_without_conditional_rules(self, mock_stdout):
        self.payment_processor.add_item_to_process('membership')
        self.payment_processor.add_item_to_process('stove')
        self.payment_processor.add_item_to_process('digital_item')
        expected_output = '''Upgrading the user to "pro" account.
Printing "safety instructions"
Sending email to download digital items.
'''
        self.payment_processor.process_items()
        self.assertMultiLineEqual(mock_stdout.getvalue(), expected_output)

    @patch('sys.stdout', new_callable=StringIO)
    @patch('builtins.input')
    def test_process_items_book_conditional_rule_yes(self, mock_input, mock_stdout):
        mock_input.return_value = 'Y'
        self.payment_processor.add_item_to_process('book')
        expected_output = '''Printing mailing label.
Sending commission to the agent.
'''
        self.payment_processor.process_items()
        self.assertMultiLineEqual(mock_stdout.getvalue(), expected_output)

    @patch('sys.stdout', new_callable=StringIO)
    @patch('builtins.input')
    def test_process_items_book_conditional_rule_no(self, mock_input, mock_stdout):
        mock_input.return_value = 'n'
        self.payment_processor.add_item_to_process('book')
        expected_output = '''Printing mailing label.
'''
        self.payment_processor.process_items()
        self.assertMultiLineEqual(mock_stdout.getvalue(), expected_output)

    @patch('sys.stdout', new_callable=StringIO)
    @patch('builtins.input')
    def test_process_items(self, mock_input, mock_stdout):
        mock_input.return_value = 'Y'
        self.payment_processor.add_item_to_process('book')
        self.payment_processor.add_item_to_process('membership')
        self.payment_processor.add_item_to_process('stove')
        self.payment_processor.add_item_to_process('digital_item')
        expected_output = '''Printing mailing label.
Sending commission to the agent.
Upgrading the user to "pro" account.
Printing "safety instructions"
Sending email to download digital items.
'''
        self.payment_processor.process_items()
        self.assertMultiLineEqual(mock_stdout.getvalue(), expected_output)

test_shopping_cart.py

'''Tests for the ShoppingCart class.
Author: Animesh Ghosh
'''
import unittest
from shopping_cart import ShoppingCart


class TestShoppingCart(unittest.TestCase):
    def setUp(self):
        self.cart = ShoppingCart()

    def test_add_item_incorrect_type(self):
        self.assertRaises(TypeError, self.cart.add_item, True)
        self.assertRaises(TypeError, self.cart.add_item, 3.75)
        self.assertRaises(TypeError, self.cart.add_item, 4)

    def test_add_item_unsupported_item(self):
        self.assertRaises(ValueError, self.cart.add_item, 'orange')
        self.assertRaises(ValueError, self.cart.add_item, 'butter')

    def test_get_total_price(self):
        # milk,milk, bread,banana,bread,bread,bread,milk,apple
        self.cart.add_item('milk')
        self.cart.add_item('milk')
        self.cart.add_item('bread')
        self.cart.add_item('banana')
        self.cart.add_item('bread')
        self.cart.add_item('bread')
        self.cart.add_item('bread')
        self.cart.add_item('milk')
        self.cart.add_item('apple')
        self.assertAlmostEqual(self.cart.get_total_price(), 19.02)

    def test_get_amount_saved(self):
        # milk,milk, bread,banana,bread,bread,bread,milk,apple
        self.cart.add_item('milk')
        self.cart.add_item('milk')
        self.cart.add_item('bread')
        self.cart.add_item('banana')
        self.cart.add_item('bread')
        self.cart.add_item('bread')
        self.cart.add_item('bread')
        self.cart.add_item('milk')
        self.cart.add_item('apple')
        self.assertAlmostEqual(self.cart.get_amount_saved(), 3.45)


if __name__ == '__main__':
    unittest.main()