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How can I unit test a function that is called by another function

I am trying to unit test my program and have decided to unit test the withdraw_cash function. However, it is called by the bank_atm function. I have never called a function that is dependent on another function and am confused about how to do this. Would i use mock and patch to do this?
The tests would be:
check whether entering valid amount
check whether amount is less than balance
user = {
'pin': 1234,
'balance': 100
}
def withdraw_cash():
while True:
try:
amount = int(input("Enter the amount of money you want to withdraw: "))
except ValueError as v:
print(f"Enter correct amount: ")
else:
if amount > user['balance']:
raise ValueError("You don't have sufficient balance to make this withdrawal")
else:
user['balance'] = user['balance'] - amount
print(f"£{user['balance']}")
return
finally:
print("Program executed")
def bank_atm():
count = 0
to_exit = False
while (count < 3) and (not to_exit):
try:
pin = int(input('Please enter your four digit pin: '))
except ValueError:
print("Please enter correct pin")
count += 1
if pin != user['pin']:
print("Pin does not match.. Try Again")
count += 1
else:
withdraw_cash()
to_exit = True
if count == 3:
print('3 UNSUCCESFUL PIN ATTEMPTS, EXITING')
print('!!!!!YOUR CARD HAS BEEN LOCKED!!!!!')
try:
bank_atm()
except ValueError as v:
print(f"ERROR: {v}")

To expand on the comments. Put UI interactions in separate functions, such as getpin and getpounds. They can then be tested separately from the business functions. One can either mix manual input with the unittests or automate them by patching sys.stdin/out. My proof-of-concept experiment, which passes on 3.11.0b3 run from IDLE editor.
import sys
import unittest
from unittest.mock import patch
def getpin(realpin):
return input('Your pin? ') == realpin
class ManualTest(unittest.TestCase):
def test_pin(self):
print('\n(Enter 1234)')
self.assertEqual(getpin('1234'), True)
print('\n(Enter 1)')
self.assertEqual(getpin('1234'), False)
class MockOut:
def write(self, string): pass
# Or 'write = Mock()' to save and check prompts, using mockout.
class MockIn:
def readline(self): # input() uses readline, not read.
return self.line
#patch('sys.stdin', new_callable=MockIn)
#patch('sys.stdout', new_callable=MockOut)
class AutoTest(unittest.TestCase):
def test_pin(self, mockout, mockin):
mockin.line='1234\n' # input removes '\n' if present.
self.assertEqual(getpin('1234'), True)
mockin.line='1233'
self.assertEqual(getpin('1234'), False)
if __name__ == '__main__':
unittest.main(verbosity=2)

I have now refactored my program, by breaking it down into separate functions as you said but when I try and run a test specifically for one function, it runs the whole thing and asks for input from each function. I feel like testing each function individually will have to require specific parameters not dependent on the other function.
user = {
'pin': 1234
}
def withdraw_cash(amount):
balance_account = 100
if amount > balance_account:
raise ValueError("You don't have sufficient balance to make this withdrawal")
else:
new_balance = balance_account - amount
return new_balance
def get_pin():
count = 0
to_exit = False
while (count < 3) and (not to_exit):
try:
pin = int(input('Please enter your four digit pin: '))
except ValueError:
print("Please enter correct pin")
count += 1
if pin != user['pin']:
print("Pin does not match.. Try Again")
count += 1
else:
return get_amount(pin)
#return pin
if count == 3:
a = '3 UNSUCCESFUL PIN ATTEMPTS, EXITING \n !!!!!YOUR CARD HAS BEEN LOCKED!!!!!'
return a
def get_amount(pin):
while True:
try:
amount = int(input("Enter the amount of money you want to withdraw: "))
except ValueError as v:
print(f"Enter correct amount: ")
else:
#print(amount)
return withdraw_cash(amount)
#return amount
try:
get_pin()
except ValueError as v:
print(f"ERROR: {v}")

How to break between loop by creating a condition in python

lst = []
while True:
try:
arr = int(input("Enter number of elements: "))
if arr == "Quit":
break
except ValueError:
print("Invalid Input")
continue
else:
break
while True:
try:
for i in range(0, arr):
ele = int(input("Enter the elements:"))
lst.append(ele)
print(lst)
except ValueError:
print("Invalid Input")
continue
else:
break
How can I create a condition to exit the program at any point in the loop by specifically entering the conditioned term?
Like when it asks me to enter an element, but i want to break the program right at that point by entering
"Quit".
How to do that in this code?
(Learner)

Use sys.exit() to exit the program completely. Use break to exit the specific loop you're in (which you've used).
Other notes:
You're doing arr = int(input(...)) but you want to accept the input of "Quit" which is a string. So if the user enters "Quit", it raise ValueError and the loop continues. So check for "Quit" first and if it's not quit, then convert to int with the try-block
Same applies for the 2nd loop where you ask the user for the elements in the list
Btw, your second loop's while True loop should be inside the for-loop which gets each element.
lst = []
while True:
arr = input("Enter number of elements: ")
if arr == "Quit":
sys.exit() # will exit completely
try:
arr = int(arr) # check for int in the try-block, error raised here, if not int
break # can put break here instead of in else, any is okay
except ValueError:
print("Invalid Input")
# continue not needed here, since it loops infinitely by default
for i in range(0, arr):
while True:
ele = input("Enter the elements:")
if ele == "Quit":
sys.exit() # will exit completely
try:
ele = int(ele) # check for int in the try-block, error raised here, if not int
lst.append(ele)
break # breaks out of `while` loop, not `for` loop; good
except ValueError:
print("Invalid Input")
# continue not needed here, since it loops infinitely by default
print(lst) # print the full list after all the inputs
The pattern for your input is repeated:
Ask user for input
if input is "Quit", then exit completely
otherwise, convert the input to an int
So this can put into a function, which you call in both places:
def int_or_quit(msg):
"""`msg` is the message you want to show at input"""
while True:
item = input(msg)
if item == "Quit":
sys.quit() # will exit completely
try:
return int(item) # try converting to int and return
except ValueError:
print("Invalid Input")
# repeats by default
# use the function above in your two code blocks, which are now simplified:
lst = []
arr = int_or_quit("Enter number of elements: ")
# program exits before if user "Quit", next part won't execute
for i in range(0, arr):
ele = int_or_quit("Enter an element:")
lst.append(ele)
print(lst)

I can see that there're 2 blocks in your code snippet. I'd suggest organising them in distinct functions, where function name infers a function goal (instead of comments):
def get_list_size():...
def fill_list():...
Next thing to do is deciding about function's return values:
from typing import List, Optional
def get_list_size() -> Optional[int]:
"""
:returns: number of desired elements of list or None, if "Quit" was pressed
:raises: ValueError exception, if non integer value was pressed
"""
def fill_list(lst_size: int) -> List[int]:
"""
returns: filled list
throws: ValueError exception, if non integer value was pressed
"""
Here you can see, how Optional type hint is used to add condition logic into the program.
Lats thing to do is to fill your functions with lightweight code:
def get_list_size() -> Optional[int]:
"""
:returns: number of desired elements of list or None, if "Quit" was pressed
:raises: ValueError exception, if non integer value was pressed
"""
while True:
try:
input_value = input("Enter number of elements: ")
# Pay attention: you have to check string input_value, not int(input_value).
# Checking int(input_value) would raise exception before 'Quit' validation.
if input_value == "Quit":
return None
return int(input_value)
# Could be rewritten as trinary if
# return None if input_value == "Quit" else int(input_value)
except ValueError:
print("Invalid Input")
# continue <- Not needed here
def fill_list(lst_size: int) -> List[int]:
"""
returns: filled list
throws: ValueError exception, if non integer value was pressed
"""
lst = []
while len(lst) < lst_size:
try:
ele = int(input("Enter the elements:"))
lst.append(ele)
print(lst)
except ValueError:
print("Invalid Input")
return lst
Pay attention: in fill_list function you have to try/except each element, so while loop was moved outside.
Last thing to do is running these functions:
desired_list = []
desired_list_size = get_list_size()
if desired_list_size is not None:
desired_list = fill_list(desired_list_size)

def one():
message = ""
while message != "Quit":
message = input("Type in Order > ")
if message == "Run":
print("Run some Code")
message = input("What do u want to run ? > ")
if message == "Exel":
print("Runing Exel")
else:
pass
else:
pass
while True:
one()
Here you can pass in funktions that will run when you call it by its Name. If u write Quit it will start over again. It starts over again if you write something wrong. U could do an FailExeption for that if u want to.

why does this python while loop not work in the program?

I'm trying to run the program in the following article:
https://blockgeeks.com/guides/python-blockchain-2/
I've copied all of the code into my Spyder IDE. When i run it there's a while loop which starts up asking the user to choose a number from the list of options it prints.
After selecting a number the program should perform the requested action. When i select it though it just loops back to the start of the while loop.
It appears to be ignoring the rest of the code in the while loop (the if statement part).
Confusingly if i take the parts of the code from the program which are used in the while loop and run them separately they work i.e if i run the below code and select the number 1 for my choice it will run the code in the if statement.
Why would the if statement run here but not in the main program?
#function 1:
def get_user_choice():
user_input = input("enter a number: ")
return user_input
#function 2:
def get_transaction_value():
tx_recipient = input('Enter the recipient of the transaction: ')
tx_amount = float(input('Enter your transaction amount '))
return tx_recipient, tx_amount
while True:
print("Choose an option")
print('Choose 1 for adding a new transaction')
print('Choose 2 for mining a new block')
print('Choose 3 for printing the blockchain')
print('Choose anything else if you want to quit')
user_choice = get_user_choice()
if user_choice == '1':
tx_data = get_transaction_value()
print(tx_data)
Update:
Sorry i realise i may not have been very clear what the problem is.
The above code is part of the code from the entire program and runs as expected in isolation from the main program.
The below code is the entire program from the article in the link. It includes all of the code in the program. If i run this main program the while loop doesn't use the if statement. It appears to just be breaking straight out of the loop after i select 1, 2 or 3 (any other number should break out of the loop anyway).
Here's a link for a screen shot showing what the console looks like after i have selected the number 1 for the option.
https://ibb.co/RNy2r0m
# Section 1
import hashlib
import json
reward = 10.0
genesis_block = {
'previous_hash': '',
'index': 0,
'transaction': [],
'nonce': 23
}
blockchain = [genesis_block]
open_transactions = []
owner = 'Blockgeeks'
def hash_block(block):
return hashlib.sha256(json.dumps(block).encode()).hexdigest()
# Section 2
def valid_proof(transactions, last_hash, nonce):
guess = (str(transactions) + str(last_hash) + str(nonce)).encode()
guess_hash = hashlib.sha256(guess).hexdigest()
print(guess_hash)
return guess_hash[0:2] == '00'
def pow():
last_block = blockchain[-1]
last_hash = hash_block(last_block)
nonce = 0
while not valid_proof(open_transactions, last_hash, nonce):
nonce += 1
return nonce
# Section 3
def get_last_value():
""" extracting the last element of the blockchain list """
return(blockchain[-1])
def add_value(recipient, sender=owner, amount=1.0):
transaction = {'sender': sender,
'recipient': recipient,
'amount': amount}
open_transactions.append(transaction)
# Section 4
def mine_block():
last_block = blockchain[-1]
hashed_block = hash_block(last_block)
nonce = pow()
reward_transaction = {
'sender': 'MINING',
'recipient': owner,
'amount': reward
}
open_transactions.append(reward_transaction)
block = {
'previous_hash': hashed_block,
'index': len(blockchain),
'transaction': open_transactions,
'nonce': nonce
}
blockchain.append(block)
# Section 5
def get_transaction_value():
tx_recipient = input('Enter the recipient of the transaction: ')
tx_amount = float(input('Enter your transaction amount '))
return tx_recipient, tx_amount
def get_user_choice():
user_input = input("Please give your choice here: ")
return user_input
# Section 6
def print_block():
for block in blockchain:
print("Here is your block")
print(block)
# Section 7
while True:
print("Choose an option")
print('Choose 1 for adding a new transaction')
print('Choose 2 for mining a new block')
print('Choose 3 for printing the blockchain')
print('Choose anything else if you want to quit')
user_choice = get_user_choice()
if user_choice == 1:
tx_data = get_transaction_value()
recipient, amount = tx_data
add_value(recipient, amount=amount)
print(open_transactions)
elif user_choice == 2:
mine_block()
elif user_choice == 3:
print_block()
else:
break
[1]: https://i.stack.imgur.com/FIrn7.png

When comparing values, Python takes a stronger route regarding data types than some other languages. That means no string in Python will equal a number.
Or in other terms "1" == 1 will be False.
That means you have to consider that in Python 3 you will receive a string from input() (not necessarily so in Python 2).
You can either compare this directly to another string:
user_choice = input()
if user_choice == "1":
print("You chose item 1")
Or you can convert it into a number first and compare it to a number:
user_choice = int(input())
if user_choice == 1:
print("You chose item 1")
Note that in the former case it might not be robust if the user enters extra spaces and in the latter case it will fail very loudly with an exception if the user doesn't enter an integer (or even nothing at all).
Both ways can be handled with extra code if necessary. In the former case, you can strip whitespace with user_input = input().strip() and in the latter case you can catch the exception with a try ... except ... block.

You have only handled the case for user_choice == '1'. If you enter anything other than 1, the program will return control to the beginning of the while loop.
I'll suggest you use a debugger to see what user_choice is before the if condition. If not, just use prints.
print("user_choice: {}, type: {}".format(user_choice, type(user_choice))

How to exit a while loop when the input or variable in a user-defined function meets the condition in Python [duplicate]

This question already has answers here:
How to break out of while loop in Python?
(5 answers)
Closed 4 years ago.
I'm trying to use a while loop to iterate through a function in Python which requests a user input, i.e. commitchanges to perform one of two actions, and if the input is not valid after a few attempts to close the program.
If the input is equal to 'y' (Yes) then the program should commit the changes made by the SQL update query, i.e. conn.commit()
If the input is equal to 'n' (No) then the program should not commit the changes and rollback, i.e. conn.rollback()
If the input is anything other than 'y' or 'n' then the program should alert the user that that is not a valid input.
Here's my current function:
def action(inputattempts):
commitchanges = input()
if commitchanges.lower() == 'y':
try:
conn.commit()
print ('Table Updated. No. of records updated:', totalupdates)
except cx_Oracle.DatabaseError as error:
print(error)
elif commitchanges.lower() == 'n':
conn.rollback()
print ('Rollback - No updates made to table')
else:
print ('Not a valid selection - Try again')
print (inputattempts)
Where the variable totalupdates is a global variable defined later on in the program which counts the number of records affected by the curs.execute SQL query.
I'm then calling the above function in a while loop as follows:
inputattempts = 0
while (inputattempts < 4):
inputattempts += 1
action(inputattempts)
print ('FAILED')
Essentially, I'd like the user to have a maximum of 4 attempts at entering a valid input, i.e. 'y' or 'n' before the program aborts if the input is not valid after those attempts. However, if 'y' or 'n' is entered the first time the function is called the program should either commit or rollback and exit the loop.
Currently, I'm having to complete 4 iterations of the while loop regardless of my input. Is there a way I can tweak any of that syntax to exit the loop when the above conditions are met?

As suggested by #rdimaio:
Your action function returns True if the flow was valid; False otherwise (i.e. invalid user input).
def action(inputattempts):
commitchanges = input()
if commitchanges.lower() == 'y':
try:
conn.commit()
print ('Table Updated. No. of records updated:', totalupdates)
except cx_Oracle.DatabaseError as error:
print(error)
return True
elif commitchanges.lower() == 'n':
conn.rollback()
print ('Rollback - No updates made to table')
return True
print ('Not a valid selection - Try again')
print (inputattempts)
return False
Then, you check whether the flow was valid in your while and break when condition is met:
input_attempts = 0
while input_attempts < 4:
input_attempts += 1
if action(input_attempts):
break
if input_attempts == 4:
print ('FAILED')

Just get the user input outside of actions() and pass it as a parameter:
while inputattempts < 4:
inputattempts += 1
commit_changes = input()
action(inputattempts, commit_changes)
Then after the call to action() you can condition on what you need and break out if appropriate.

You can return a value from your function and check over it's returned value to break or not.
def action(inputattempts):
correct_input = True
commitchanges = input()
if commitchanges.lower() == 'y':
try:
conn.commit()
print ('Table Updated. No. of records updated:', totalupdates)
except cx_Oracle.DatabaseError as error:
print(error)
elif commitchanges.lower() == 'n':
conn.rollback()
print ('Rollback - No updates made to table')
else:
print ('Not a valid selection - Try again')
print (inputattempts)
correct_input = False
return correct_input
then change your while loop to break the loop when
inputattempts = 0
while (inputattempts < 4):
inputattempts += 1
if action(inputattempts):
break
print ('FAILED')

Have your function return a flag telling whether or not the input was accepted:
def action(inputattempts):
commitchanges = input()
if commitchanges.lower() == 'y':
try:
conn.commit()
print ('Table Updated. No. of records updated:', totalupdates)
return True # <-- New
except cx_Oracle.DatabaseError as error:
print(error)
elif commitchanges.lower() == 'n':
conn.rollback()
print ('Rollback - No updates made to table')
return True # <-- New
else:
print ('Not a valid selection - Try again')
print (inputattempts)
return False # <-- New
Now in your loop, you can do
inputattempts = 0
while (inputattempts < 4):
inputattempts += 1
if action(inputattempts):
break
print ('FAILED')
where the break simply exists the loop. Also, I imagine that the print of 'FAILED' should only occur if the loop is exited after the 4 attempts, not if the break was reached. This can be achieved using else. Finally, your while loop really only counts, and so a for loop is more appropriate. Consider
for inputattempts in range(4):
if action(inputattempts):
break
else:
print ('FAILED')

Why can't I call a function here?

Hi guys I was working on a shoppinglist-creator code but at the end I faced with a surprise.
My code:
import time
import math
import random
dict_of_lists={}
def addlist():
while True:
try:
listname=str(raw_input("=>Name of the list:\n"))
dict_of_lists[listname]={}
break
except ValueError:
print "=>Please enter a valid name.\n"
print "=>You added a new list named %s.\n" % (listname)
def printlists():
for lists in dict_of_lists:
return "-"+lists
def addproduct():
while True:
try:
reachlistname=input("=>Name of the list you want to add a product,Available lists are these:\n %s \nPlease enter one:\n" % (printlists()))
break
except ValueError:
print "=>Please enter a valid list name.\n"
while True:
try:
productname=raw_input("=>Name of the product:\n")
break
except ValueError:
print "=>Please enter a valid name.\n"
while True:
try:
productprice=input("=>Price of the product:\n")
if isinstance(float(productprice),float):
break
except ValueError:
print "=>Please enter a valid number.\n"
while True:
try:
productcount=input("=>Amount of the product:\n")
if isinstance(int(productcount),int):
break
except ValueError:
print "=>Please enter a valid number.\n"
dict_of_lists[reachlistname][productname]={"price":productprice,"count":productcount}
dict_of_lists[reachlistname]={productname:{"price":productprice,"count":productcount}}
allevents="1-Add a list"+" 2-Add a product to a list"
def eventtochoose():
while True:
try:
event=raw_input("=>What would you like to do? Here are the all things you can do:\n %s\nPlease enter the number before the thing you want to do:" % (allevents))
if not isinstance(int(event),int):
print "\n=>Please enter a number.\n"
else:
if event==1:
addlist()
break
elif event==2:
addproduct()
break
except ValueError:
print "\n=>Please enter a valid input.\n "
while True:
print "%s" % ("\n"*100)
eventtochoose()
So, the problem is (I suggest you run the code) it says "=>What would you like to do? Here are the all things you can do:
1-Add a list 2-Add a product to a list
Please enter the number before the thing you want to do:" and when i put an answer it simply doesn't call the fucntion.
If I put 1 It should have called the fucntion addlist but I think it doesn't. There is nothing to explain I think just look at the code and find the problem if you want to help crocodiles. Thx

When you do int(event), that returns an int if possible, and raises a ValueError if not. So, testing the type of the result doesn't do you any good—if your code gets that far, the type has to be an int.
You already have code to handle the ValueError, so you don't need any other test for the same problem.
Meanwhile, you want to start the number that you got from int(event). That's the thing that can be == 1; the original string '1' will never be == 1.
So:
while True:
try:
event=raw_input("=>What would you like to do? Here are the all things you can do:\n %s\nPlease enter the number before the thing you want to do:" % (allevents))
event = int(event)
if event==1:
addlist()
break
elif event==2:
addproduct()
break
except ValueError:
print "\n=>Please enter a valid input.\n "

You are not converting your input to an integer before comparing, so the comparisons are always false:
'1' == 1 # false
Try:
event = raw_input("=>What would you like to do? Here are the all things you can do:\n %s\nPlease enter the number before the thing you want to do:" % (allevents))
try:
event = int(event)
if event == 1:
addlist()
elif event == 2:
addproduct()
break
except ValueError:
print('Please enter a valid input')