Cara menggunakan python cookiejar

Suppose that you’d like to implement a cookie jar in which to store cookies. In a file called jar.py, implement a class called Jar with these methods:

• __init__ should initialize a cookie jar with the given capacity, which represents the maximum number of cookies that can fit in the cookie jar. If capacity is not a non-negative

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  0, though, __init__ should instead raise a

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  2.

• from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  3 should return a

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  4 with \(n\)

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  5, where \(n\) is the number of cookies in the cookie jar. For instance, if there are 3 cookies in the cookie jar, then

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  4 should return

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  7

• from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  8 should add

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  9 cookies to the cookie jar. If adding that many would exceed the cookie jar’s capacity, though,

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  8 should instead raise a

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  2.

• check50 cs50/problems/2022/python/jar
  

  2 should remove

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  9 cookies from the cookie jar. Nom nom nom. If there aren’t that many cookies in the cookie jar, though,

  check50 cs50/problems/2022/python/jar
  

  2 should instead raise a

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  2.
• capacity should return the cookie jar’s capacity.

• check50 cs50/problems/2022/python/jar
  

  7 should return the number of cookies actually in the cookie jar.

Structure your class per the below. You may not alter these methods’ parameters, but you may add your own methods.

class Jar:
    def __init__(self, capacity=12):
        ...

    def __str__(self):
        ...

    def deposit(self, n):
        ...

    def withdraw(self, n):
        ...

    @property
    def capacity(self):
        ...

    @property
    def size(self):
        ...

Either before or after you implement jar.py, additionally implement, in a file called

submit50 cs50/problems/2022/python/jar

submit50 cs50/problems/2022/python/jar

Note that it’s not as easy to test instance methods as it is to test functions alone, since instance methods sometimes manipulate the same “state” (i.e., instance variables). To test one method (e.g.,

check50 cs50/problems/2022/python/jar

from jar import Jar


def test_init():
    ...


def test_str():
    jar = Jar()
    assert str(jar) == ""
    jar.deposit(1)
    assert str(jar) == "🍪"
    jar.deposit(11)
    assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"


def test_deposit():
    ...


def test_withdraw():
    ...

And so programmers sometimes mock (i.e., simulate) state when testing methods, as with Python’s own mock object library, so that you can call just the one method but modify the underlying state first, without calling the other method to do so.

For simplicity, though, no need to mock any state. Implement your tests as you normally would!

from jar import Jar


def test_init():
    ...


def test_str():
    jar = Jar()
    assert str(jar) == ""
    jar.deposit(1)
    assert str(jar) == "🍪"
    jar.deposit(11)
    assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"


def test_deposit():
    ...


def test_withdraw():
    ...

Demo

You’re welcome, but not required, to implement a

submit50 cs50/problems/2022/python/jar

Source: Sesame Street

Before You Begin

Log into code.cs50.io, click on your terminal window, and execute

submit50 cs50/problems/2022/python/jar

Next execute

to make a folder called

submit50 cs50/problems/2022/python/jar

Then execute

to change directories into that folder. You should now see your terminal prompt as

submit50 cs50/problems/2022/python/jar

to make a file called jar.py where you’ll write your program. You can also execute

to create a file called

submit50 cs50/problems/2022/python/jar

How to Test

Here’s how to test your code manually:

• Open your

  submit50 cs50/problems/2022/python/jar
  

  0 file and import your Jar class with jar.py3. Create a function called jar.py4, wherein you create a new instance of Jar with jar.py6. jar.py7 that this jar has the capacity it should, then run your tests with jar.py8.
• Add another function to your

  submit50 cs50/problems/2022/python/jar
  

  0 file called class0. In class0, create a new instance of your Jar class and

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  8 a few cookies. jar.py7 that class5 prints out as many cookies as have been

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  8ed, then run your tests with jar.py8.
• Add another function to your

  submit50 cs50/problems/2022/python/jar
  

  0 file called class9. In class9, create a new instance of your Jar class and

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  8 a few cookies. jar.py7 that the jar’s

  check50 cs50/problems/2022/python/jar
  

  7 attribute is as large as the number of cookies that have been

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  8ed. Also jar.py7 that, if you deposit more than the jar’s capacity,

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  8 should raise a

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  2. Run your tests with jar.py8.
• Add another function to your

  submit50 cs50/problems/2022/python/jar
  

  0 file called __init__2. In __init__2, create a new instance of your Jar class and first

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  8 a few cookies. jar.py7 that

  check50 cs50/problems/2022/python/jar
  

  2ing from the jar leaves the appropriate number of cookies in the jar’s

  check50 cs50/problems/2022/python/jar
  

  7 attribute. Also jar.py7 that, if you withdraw more than the jar’s

  check50 cs50/problems/2022/python/jar
  

  7,

  check50 cs50/problems/2022/python/jar
  

  2 should raise a

  from jar import Jar
  
  
  def test_init():
      ...
  
  
  def test_str():
      jar = Jar()
      assert str(jar) == ""
      jar.deposit(1)
      assert str(jar) == "🍪"
      jar.deposit(11)
      assert str(jar) == "🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪🍪"
  
  
  def test_deposit():
      ...
  
  
  def test_withdraw():
      ...
  

  2. Run your tests with jar.py8.

You can execute the below to check your code using capacity4, a program that CS50 will use to test your code when you submit. But be sure to test it yourself as well!

check50 cs50/problems/2022/python/jar

Green smilies mean your program has passed a test! Red frownies will indicate your program output something unexpected. Visit the URL that capacity4 outputs to see the input capacity4 handed to your program, what output it expected, and what output your program actually gave.