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Unit 6

Development Team Project: Project Report​

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Jupyter Notebook Activity​

Task

The following task involves experimenting with pytest using the Python programming language.  The pytest question should be completed in a Jupyter Notebook  Remember to save your work to your GitHub repository.

Copy the following code into a file named wallet.py:

# code source: https://semaphoreci.com/community/tutorials/testing-python-applications-with-pytest
# wallet.py
 class InsufficientAmount(Exception):
    pass
  
class Wallet(object):
     def __init__(self, initial_amount=0):
        self.balance = initial_amount
 
    def spend_cash(self, amount):
        if self.balance < amount:
            raise InsufficientAmount('Not enough available to spend {}'.format(amount))
        self.balance -= amount
 
    def add_cash(self, amount):
        self.balance += amount

Copy the following code into a file named test_wallet.py:

# code source: https://semaphoreci.com/community/tutorials/testing-python-applications-with-pytest
 # test_wallet.py
 import pytest
from wallet import Wallet, InsufficientAmount

def test_default_initial_amount():
    wallet = Wallet()
    assert wallet.balance == 0
 
def test_setting_initial_amount():
    wallet = Wallet(100)
    assert wallet.balance == 100
 
def test_wallet_add_cash():
    wallet = Wallet(10)
    wallet.add_cash(90)
    assert wallet.balance == 100
 
def test_wallet_spend_cash():
    wallet = Wallet(20)
    wallet.spend_cash(10)
    assert wallet.balance == 10
 
def test_wallet_spend_cash_raises_exception_on_insufficient_amount():
    wallet = Wallet()
    with pytest.raises(InsufficientAmount):
        wallet.spend_cash(100)

Run the tests using the command: $ pytest -q test_wallet.py You should see the following output:

5 passed in 0.02s

Amend the code so that the tests fail.

To make the tests fail, these changes can be made:

  1. Adjust the default value of the initial_amount parameter in the wallet constructor (affects test_default_initial_amount())
  2. Assign a value different from the initial_amount to the balance field of a wallet (affects test_default_initial_amount(), test_setting_initial_amount(), test_wallet_add_cash(), test_wallet_spend_cash())
  3. Adjust the amount of spent or added cash in spend_cash() and add_cash() (affects test_wallet_add_cash(), test_wallet_spend_cash())
  4. Invert the verification of available funds in spend_cash() (affects test_wallet_spend_cash(), test_wallet_spend_cash_raises_exception_on_insufficient_amount())
wallet.py
# code source: https://semaphoreci.com/community/tutorials/testing-python-applications-with-pytest  
# wallet.py  
class InsufficientAmount(Exception):  
    pass  
  
  
class Wallet(object):  
    def __init__(self, initial_amount=10):  
        self.balance = initial_amount + 10  
  
    def spend_cash(self, amount):  
        if self.balance > amount:  
            raise InsufficientAmount('Not enough available to spend {}'.format(amount))  
        self.balance -= amount  
  
    def add_cash(self, amount):  
        self.balance += (amount - 100)