Practice Quiz: Understanding the Problem

6. When a user reports that an "application doesn't work," what is an appropriate follow-up question to gather more information about the problem?

  • Is the server plugged in?
  • Why do you need the application?
  • Do you have a support ticket number?
  • What should happen when you open the app?

7. What is a heisenbug?

  • The observer effect.
  • A test environment.
  • The root cause.
  • An event viewer.

8. The compare_strings function is supposed to compare just the alphanumeric content of two strings, ignoring upper vs lower case and punctuation. But something is not working. Fill in the code to try to find the problems, then fix the problems.

import re
def compare_strings(string1, string2):
#Convert both strings to lowercase
#and remove leading and trailing blanks
string1 = string1.lower().strip()
string2 = string2.lower().strip()

#Ignore punctuation
punctuation = r"[.?!,;:-']"
string1 = re.sub(punctuation, r"", string1)
string2 = re.sub(punctuation, r"", string2)

#DEBUG CODE GOES HERE
print(___)

return string1 == string2

print(compare_strings("Have a Great Day!", "Have a great day?")) # True
print(compare_strings("It's raining again.", "its raining, again")) # True
print(compare_strings("Learn to count: 1, 2, 3.", "Learn to count: one, two, three.")) # False
print(compare_strings("They found some body.", "They found somebody.")) # False

  • import re #to use regular expressions

    def compare_strings(string1, string2): #function compare_strings that takes two strings as argument and compares them

    string1 = string1.lower().strip() # converts the string1 characters to lowercase using lower() method and removes trailing blanks

    string2 = string2.lower().strip() # converts the string1 characters to lowercase using lower() method and removes trailing blanks

    punctuation = r”[-.?!,;:’]” #regular expression for punctuation characters

    string1 = re.sub(punctuation, r””, string1) # specifies RE pattern i.e. punctuation in the 1st argument, new string r in 2nd argument, and a string to be handle i.e. string1 in the 3rd argument

    string2 = re.sub(punctuation, r””, string2) # same as above statement but works on string2 as 3rd argument

    print(‘string1:’,string1,’\nstring2:’,string2) #prints both the strings separated with a new line

    return string1 == string2 # compares strings and returns true if they matched else false

    #function calls to test the working of the above function compare_strings

    print(compare_strings(“Have a Great Day!”,”Have a great day?”)) # True

    print(compare_strings(“It’s raining again.”,”its raining, again”)) # True

    print(compare_strings(“Learn to count: 1, 2, 3.”,”Learn to count: one, two, three.”)) # False

    print(compare_strings(“They found some body.”,”They found somebody.”)) # False

9. How do we verify if a problem is still persisting or not?

  • Restart the device or server hardware
  • Attempt to trigger the problem again by following the steps of our reproduction case
  • Repeatedly ask the user
  • Check again later

10. The datetime module supplies classes for manipulating dates and times, and contains many types, objects, and methods. You've seen some of them used in the dow function, which returns the day of the week for a specific date. We'll use them again in the next_date function, which takes the date_string parameter in the format of "year-month-day", and uses the add_year function to calculate the next year that this date will occur (it's 4 years later for the 29th of February during Leap Year, and 1 year later for all other dates). Then it returns the value in the same format as it receives the date: "year-month-day".

Can you find the error in the code? Is it in the next_date function or the add_year function? How can you determine if the add_year function returns what it's supposed to? Add debug lines as necessary to find the problems, then fix the code to work as indicated above.

import datetime
from datetime import date

def add_year(date_obj):
try:
new_date_obj = date_obj.replace(year = date_obj.year + 1)
except ValueError:
# This gets executed when the above method fails,
# which means that we're making a Leap Year calculation
new_date_obj = date_obj.replace(year = date_obj.year + 4)
return new_date_obj

def next_date(date_string):
# Convert the argument from string to date object
date_obj = datetime.datetime.strptime(date_string, r"%Y-%m-%d")
next_date_obj = add_year(date_obj)

# Convert the datetime object to string,
# in the format of "yyyy-mm-dd"
next_date_string = next_date_obj.strftime("yyyy-mm-dd")
return next_date_string

today = date.today() # Get today's date
print(next_date(str(today)))
# Should return a year from today, unless today is Leap Day

print(next_date("2021-01-01")) # Should return 2022-01-01
print(next_date("2020-02-29")) # Should return 2024-02-29

  • import datetime
    from datetime import date

    def add_year(date_obj):
    print(f”Original date: {date_obj}”)
    try:
    new_date_obj = date_obj.replace(year = date_obj.year + 1)
    print(f”New date: {new_date_obj}”)
    except ValueError:
    # This gets executed when the above method fails,
    # which means that we’re making a Leap Year calculation
    new_date_obj = date_obj.replace(year = date_obj.year + 4)
    print(f”New date: {new_date_obj} (leap year)”)
    return new_date_obj

    def next_date(date_string):
    # Convert the argument from string to date object
    date_obj = datetime.datetime.strptime(date_string, r”%Y-%m-%d”)
    next_date_obj = add_year(date_obj)

    # Convert the datetime object to string,
    # in the format of “yyyy-mm-dd”
    next_date_string = next_date_obj.strftime(“%Y-%m-%d”)
    return next_date_string

    today = date.today() # Get today’s date
    print(next_date(str(today)))
    # Should return a year from today, unless today is Leap Day

    print(next_date(“2021-01-01”)) # Should return 2022-01-01
    print(next_date(“2020-02-29”)) # Should return 2024-02-29
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Devendra Kumar

Project Management Apprentice at Google

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