Identifying performance bottlenecks in Testing Fundamentals - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start measuring the time before the function runs.

Testing Fundamentals

start_time = [1]()

Drag options to blanks, or click blank then click option'

Alen

Bprint

Ctime.time

Dinput

Attempts:

3 left

💡 Hint

Common Mistakes

Using print() instead of time.time()

Using len() which counts length, not time

We use time.time() to get the current time in seconds before running the code to measure elapsed time.

2fill in blank

medium

Complete the code to calculate the elapsed time after the function runs.

Testing Fundamentals

elapsed = [1]() - start_time

Drag options to blanks, or click blank then click option'

Aprint

Btime.time

Clen

Dinput

Attempts:

3 left

💡 Hint

Common Mistakes

Using print() instead of time.time()

Not subtracting start_time

We call time.time() again to get the current time after the function finishes, then subtract the start time to get elapsed time.

3fill in blank

hard

Fix the error in the code to correctly measure the time taken by the function call.

Testing Fundamentals

def test_function():
    [1]('Starting test')
    # function code here
    print('Test done')

Drag options to blanks, or click blank then click option'

Aprint

Binput

Ctime.time

Dtime.sleep

Attempts:

3 left

💡 Hint

Common Mistakes

Using time.time() as a function call without parentheses

Using time.sleep() which pauses execution

The code intends to print a message. Using print is correct here. Using time.time or time.sleep would cause errors or wrong behavior.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps each word to its length if the length is greater than 3.

Testing Fundamentals

{word: [1] for word in words if [2] > 3}

Drag options to blanks, or click blank then click option'

Alen(word)

Bword

Dword.length

Attempts:

3 left

💡 Hint

Common Mistakes

Using word.length which is not valid in Python

Using word instead of len(word) for the value

The dictionary comprehension maps each word to its length using len(word). The condition checks if len(word) > 3.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase words to their lengths if length is greater than 4.

Testing Fundamentals

{ [1]: [2] for word in words if [3] > 4 }

Drag options to blanks, or click blank then click option'

Aword.upper()

Blen(word)

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using word instead of word.upper() for the key

Using word.length which is invalid in Python

The comprehension maps the uppercase version of each word to its length. The condition checks if the length is greater than 4.

Practice

1. What is a performance bottleneck in software testing?

easy

A. A part of the software that slows down the whole system

B. A feature that adds new functionality

C. A test case that always passes

D. A tool used to write code faster

Solution

1. Step 1: Understand the meaning of bottleneck

   A bottleneck is something that limits or slows down a process.

2. Step 2: Apply this to software performance

   In software, a bottleneck is the slow part that affects the whole system's speed.

3. Final Answer:

   A part of the software that slows down the whole system -> Option A

4. Quick Check:

   Performance bottleneck = slow part [OK]

Hint: Bottleneck means slowest part slowing everything [OK]

Common Mistakes:

• Confusing bottleneck with new features
• Thinking bottleneck is a test case
• Mixing bottleneck with coding tools

2. Which of the following is the correct way to measure execution time in Python for identifying bottlenecks?

easy

A. import time; start = time.time(); # code; end = time.time(); print(end - start)

B. import datetime; print(datetime.now())

C. print('Execution time')

D. time.sleep(5)

Solution

1. Step 1: Identify timing method for measuring code duration

   Using time.time() before and after code gives elapsed seconds.

2. Step 2: Check options for correct timing usage

   import time; start = time.time(); # code; end = time.time(); print(end - start) correctly measures start and end time and calculates difference.

3. Final Answer:

   import time; start = time.time(); # code; end = time.time(); print(end - start) -> Option A

4. Quick Check:

   Use time.time() to measure duration [OK]

Hint: Use time.time() before and after code [OK]

Common Mistakes:

• Using print statements without timing
• Using datetime.now() without calculating difference
• Using sleep to measure time

3. Consider this Python code snippet measuring a function's execution time:

import time
def slow_function():
    total = 0
    for i in range(1000000):
        total += i
start = time.time()
slow_function()
end = time.time()
print(round(end - start, 2))

What is the expected output type?

medium

A. The sum of numbers from 0 to 999999

B. An error because of missing return

C. A float number showing seconds taken

D. A string 'round' printed

Solution

1. Step 1: Understand what the code measures

   The code measures time before and after running slow_function and prints the difference rounded to 2 decimals.

2. Step 2: Analyze output type

   round(end - start, 2) returns a float number representing seconds elapsed.

3. Final Answer:

   A float number showing seconds taken -> Option C

4. Quick Check:

   Timing code prints float seconds [OK]

Hint: Timing code prints float seconds elapsed [OK]

Common Mistakes:

• Thinking it prints sum instead of time
• Expecting an error due to no return
• Confusing round function output

4. You have this code snippet to find a bottleneck:

import time
start = time.time()
for i in range(1000000):
    pass
print(end - start)

What is the error and how to fix it?

medium

A. Range should be 1000 instead of 1000000

B. Missing import statement for time module

C. Use print(start - end) instead

D. Variable 'end' is not defined; define end = time.time() before print

Solution

1. Step 1: Identify the error in variable usage

   The variable 'end' is used in print but never assigned, causing a NameError.

2. Step 2: Fix by assigning end before print

   Assign end = time.time() after the loop and before print to measure elapsed time.

3. Final Answer:

   Variable 'end' is not defined; define end = time.time() before print -> Option D

4. Quick Check:

   Define end = time.time() before print [OK]

Hint: Always assign end time before printing elapsed [OK]

Common Mistakes:

• Forgetting to assign end time
• Changing range unnecessarily
• Subtracting times in wrong order

5. You run a profiler on your web app and find that database queries take 80% of the total time. What is the best next step to improve performance?

hard

A. Add more logging to the application

B. Optimize or reduce the number of database queries

C. Increase the size of the frontend assets

D. Rewrite the UI in a different framework

Solution

1. Step 1: Analyze profiler results

   Profiler shows database queries consume most time, indicating a bottleneck there.

2. Step 2: Choose action targeting bottleneck

   Optimizing or reducing queries directly addresses the slowest part to improve speed.

3. Final Answer:

   Optimize or reduce the number of database queries -> Option B

4. Quick Check:

   Fix bottleneck by optimizing slowest part [OK]

Hint: Fix bottleneck by improving slowest part first [OK]

Common Mistakes:

• Changing unrelated parts like UI or logging
• Ignoring profiler data
• Adding features instead of fixing speed