Question

This program asks the user for the initial balance or principal (e.g. $1234.56),
the interest rate (as a percentage but without the % sign), number of years, and
how frequently compounded (supports the words "daily" for 365, "weekly" for 52,
"monthly" for 12, "quarterly" for 4, and "annually" for 1.

If then displays the total accrued amount (i.e. the principal plus the interest).

The output should look exactly like money.

Make sure you create each of the functions appropriately. All input() and
print() calls are in main() [do NOT use input() or print() in any ].

The file tests.py contains the unit tests that you will write for each function.
Make sure to open that file and complete the required tests.

EXAMPLE 1:
Principal: $10000.00
Interest Rate: 3.875
Number of Years: 7.5
Frequency of Compounds (daily, weekly, monthly, quarterly, or annually): monthly
You will have accrued $13366.37

Answer 1

A simple formula can solve your problem. You need not have any complex functions in it. Since you did not specified to not use any formulae. I am just solving theses using the formula.

Note : Please mention programming language explicitly. Since you told "tests.py" as file name, I am assuming it as python and answering here.

Program :

#Input the principal

original_principal = int(input('Principal: '))

# Input the annual interest rate.

annual_interest = float(input('Interest Rate(%): '))
annual_interest = annual_interest / 100

# Input number of years account will earn interest.

total_years = float(input('Number of Years: '))

# Input times per year the interest is compounded.
c=0
while c==0:
compound = input("Frequency of Compounds (daily, weekly, monthly, quarterly, or annually):")
if compound=="annually":
c=1
elif compound=="monthly":
c=12
elif compound=="weekly":
c=52
elif compound=="daily":
c=365
elif compound=="quarterly":
c=4
else:
print("Please enter one of the option specified in brackets:")
# Calculate ending principle amount after earning
# interest for a specified amount of years.

ending_principal = (original_principal * (1 + annual_interest
/ c) ** (c * total_years)
)

# Display the ending principle amount.

print('At the end of ', total_years, 'years you will have $',
format(ending_principal, '.2f'))

Outputs :

Test case 1 :

Here I am checking it for daily basis. Also I have written the code in such a way that. if user enters any other string for compounded frequency, it warns and prompts again.

Test Case 2:

This was the test case provided by you.

Since the code is python , I am pasting the screen shot of the code so that you don't confuse with the indentation.