Interview preparation for testers in Testing Fundamentals - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Test Case Prioritization

Imagine you have 100 test cases but only time to run 20 before a release. Which approach best helps you choose which test cases to run first?

A Run test cases that cover the most critical features and recent bug fixes first.

B Run the first 20 test cases in the order they were written.

C Run test cases randomly to avoid bias.

D Run only the test cases that are easiest to execute.

💡 Hint

Think about which tests give the most value in finding important bugs quickly.

Prioritizing test cases that cover critical features and recent bug fixes helps catch important issues early, making the best use of limited testing time.

❓ Predict Output

intermediate

Test Assertion Outcome

What will be the result of this test assertion in Python?

Testing Fundamentals

def add(a, b):
    return a + b

result = add(2, 3)
assert result == 6, f"Expected 6 but got {result}"

A Test passes silently with no error.

B TypeError because add function arguments are wrong.

C SyntaxError due to incorrect assert syntax.

D AssertionError with message 'Expected 6 but got 5'.

💡 Hint

Check what the add function returns and what the assertion expects.

The add function returns 5 for inputs 2 and 3, but the assertion expects 6, so it raises an AssertionError with the message.

❓ locator

advanced

Choosing the Best Locator for UI Testing

You need to select a locator for a login button on a webpage. Which locator is best for stable and maintainable tests?

A Locate by XPath using absolute path like /html/body/div[2]/button[1].

B Locate by index position among sibling elements.

C Locate by CSS class name that is unique and descriptive, e.g., '.btn-login'.

D Locate by button text which may change, e.g., 'Click Here'.

💡 Hint

Think about what makes locators less likely to break when the page changes.

Using a unique and descriptive CSS class is more stable and maintainable than absolute XPath or text that can change.

🔧 Debug

advanced

Debugging a Failing Test Case

Given this test code snippet, what is the cause of the failure?

Testing Fundamentals

def divide(a, b):
    return a / b

def test_divide():
    result = divide(10, 0)
    assert result == 0, "Division by zero should return 0"

A The test code has a syntax error in the assert statement.

B The divide function raises a ZeroDivisionError instead of returning 0.

C The assertion expects wrong output; division by zero returns None.

D The divide function is missing and causes a NameError.

💡 Hint

Think about what happens in Python when dividing by zero.

In Python, dividing by zero raises a ZeroDivisionError unless handled inside the divide function.

❓ framework

expert

Test Framework Design for Parallel Execution

You want to run tests in parallel to speed up execution. Which framework feature is essential to avoid flaky tests?

A Tests are isolated with independent setup and teardown for each test.

B Tests share global variables to reduce memory usage.

C Tests write logs to the same file without synchronization.

D Tests depend on the order of execution to pass.

💡 Hint

Consider what causes tests to interfere with each other when run at the same time.

Isolating tests with independent setup and teardown prevents shared state issues and makes parallel runs reliable.

Practice

1. What is the main purpose of software testing in a project?

easy

A. To write code for new features

B. To find defects and ensure the software works as expected

C. To design the user interface

D. To manage the project timeline

Solution

1. Step 1: Understand the role of testing

   Testing is done to check if the software behaves correctly and to find any bugs.

2. Step 2: Compare options with testing goals

   Only To find defects and ensure the software works as expected talks about finding defects and verifying software behavior, which matches testing purpose.

3. Final Answer:

   To find defects and ensure the software works as expected -> Option B

4. Quick Check:

   Testing = Find defects + Verify behavior [OK]

Hint: Testing finds bugs and checks software works [OK]

Common Mistakes:

• Confusing testing with coding
• Thinking testing manages project tasks
• Mixing testing with design roles

2. Which of the following is the correct syntax to write a test case title?

easy

A. verify_user_login_with_valid_credentials

B. verify user login with valid credentials

C. VerifyUserLoginWithValidCredentials

D. "Verify user login with valid credentials"

Solution

1. Step 1: Identify proper test case title format

   Test case titles should be clear, descriptive, and readable, usually in sentence case with quotes.

2. Step 2: Evaluate options for clarity and format

   "Verify user login with valid credentials" uses clear sentence case with quotes, making it easy to understand. Others are less readable or informal.

3. Final Answer:

   "Verify user login with valid credentials" -> Option D

4. Quick Check:

   Clear descriptive title in quotes = "Verify user login with valid credentials" [OK]

Hint: Test case titles are clear sentences in quotes [OK]

Common Mistakes:

• Using camelCase or snake_case for titles
• Writing titles without quotes or punctuation
• Using all lowercase without clarity

3. Consider this test scenario: A login form accepts username and password. Which test case will fail if the password field allows empty input?

Test Case: Verify login with empty password
Steps:
1. Enter valid username
2. Leave password empty
3. Click login
Expected Result: Login should fail with error message

What will be the test execution result?

medium

A. Fail, because login succeeds with empty password

B. Pass, because empty password is allowed

C. Pass, because login fails as expected

D. Fail, because username is invalid

Solution

1. Step 1: Understand the test case and expected behavior

   The test expects login to fail when password is empty, showing an error.

2. Step 2: Analyze the actual behavior described

   The password field allows empty input, so login succeeds, which is against expected result.

3. Final Answer:

   Fail, because login succeeds with empty password -> Option A

4. Quick Check:

   Expected fail but login succeeds = Fail [OK]

Hint: If actual differs from expected, test fails [OK]

Common Mistakes:

• Assuming empty password is valid
• Confusing pass/fail with allowed inputs
• Ignoring expected error message

4. You wrote this test step: Click the submit button but the test fails because the button is not found. What is the most likely cause?

medium

A. The locator used to find the button is incorrect or outdated

B. The submit button does not exist in the application

C. The test script has syntax errors

D. The test environment is down

Solution

1. Step 1: Identify the failure reason for 'button not found'

   This usually means the test script cannot locate the button element on the page.

2. Step 2: Evaluate possible causes

   Incorrect or outdated locator is the most common cause, as UI changes can break locators.

3. Final Answer:

   The locator used to find the button is incorrect or outdated -> Option A

4. Quick Check:

   Button not found = Locator issue [OK]

Hint: Check locators first when element not found [OK]

Common Mistakes:

• Assuming button is missing without checking locator
• Blaming syntax errors without evidence
• Ignoring environment status

5. You have a list of test cases with their results:

[{"id":1, "result":"pass"}, {"id":2, "result":"fail"}, {"id":3, "result":"pass"}, {"id":4, "result":"fail"}]

How many test cases must be re-executed after fixing defects?

hard

A. 3

B. 4

C. 2

D. 1

Solution

1. Step 1: Identify test cases with failed results

   From the list, test cases with id 2 and 4 have result 'fail'.

2. Step 2: Determine re-execution count

   Only failed test cases need re-execution after defects are fixed, so count is 2.

3. Final Answer:

   2 -> Option C

4. Quick Check:

   Failed tests = 2 [OK]

Hint: Re-run only failed test cases after fixes [OK]

Common Mistakes:

• Counting all test cases instead of only failed
• Confusing pass with fail
• Ignoring test case results