Error guessing in Testing Fundamentals - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Identifying Error Guessing Technique Purpose

What is the main goal of the error guessing technique in software testing?

A To design test cases based on the tester's experience to find likely errors

B To automatically generate test cases using a tool

C To test only the user interface elements for errors

D To verify that the software meets all specified requirements

💡 Hint

Think about how testers use their knowledge and intuition.

Error guessing relies on the tester's experience to predict where errors might occur and create test cases accordingly.

❓ Predict Output

intermediate

Output of Error Guessing Test Case Result

Given a function that divides two numbers, a tester uses error guessing to test division by zero. What will be the output when the function is called with (10, 0)?

Testing Fundamentals

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

result = divide(10, 0)

A Zero

B 10

C Returns None

D Raises ZeroDivisionError

💡 Hint

What happens in Python when you divide by zero?

Dividing by zero in Python raises a ZeroDivisionError exception.

❓ assertion

advanced

Choosing the Correct Assertion for Error Guessing

Which assertion is best to verify that a function raises an error when given invalid input during error guessing?

Testing Fundamentals

def test_invalid_input():
    # Choose the correct assertion here
    pass

A assertRaises(ExpectedError, function, invalid_input)

B assert function(invalid_input) == 'error'

C assert function(invalid_input) is None

D assert function(invalid_input) != valid_output

💡 Hint

Look for the assertion that checks for exceptions.

assertRaises is used to check if a function raises a specific error when called with certain inputs.

🔧 Debug

advanced

Debugging a Failed Error Guessing Test

A tester wrote a test case to check for null input handling but the test passes even when the function crashes. What is the likely cause?

A The function handles null input correctly

B The function never receives null input

C The test case does not catch the exception properly

D The test case uses the wrong input value

💡 Hint

Consider how exceptions are handled in tests.

If the test does not catch exceptions, the test framework may mark the test as failed incorrectly.

❓ framework

expert

Integrating Error Guessing in Automated Testing Framework

How can error guessing be effectively integrated into an automated testing framework?

A By relying only on random test data generation without human input

B By adding test cases based on common error patterns and past bugs into the test suite

C By removing all manual test cases and using only automated scripts

D By testing only the happy path scenarios automatically

💡 Hint

Think about combining human knowledge with automation.

Error guessing works best when testers add their experience-based test cases into automated suites to catch common errors.

Practice

1. What is the main idea behind Error guessing in software testing?

easy

A. Using formal test cases only

B. Writing automated tests for every function

C. Guessing where errors might occur based on experience

D. Ignoring past bugs and testing randomly

Solution

1. Step 1: Understand the concept of error guessing

   Error guessing is a technique where testers use their experience to predict where bugs might be.

2. Step 2: Compare options with the concept

   Only Guessing where errors might occur based on experience matches the idea of using experience to guess errors, others describe different testing methods.

3. Final Answer:

   Guessing where errors might occur based on experience -> Option C

4. Quick Check:

   Error guessing = Experience-based bug prediction [OK]

Hint: Error guessing is about experience, not formal rules [OK]

Common Mistakes:

• Confusing error guessing with automated testing
• Thinking error guessing ignores tester knowledge
• Believing error guessing is random testing

2. Which of the following is a correct example of an error guessing test case?

easy

A. Test all buttons for correct color

B. Test the software without any plan

C. Test only the homepage layout

D. Test input with empty fields to check validation

Solution

1. Step 1: Identify error guessing test case traits

   Error guessing focuses on inputs or actions likely to cause errors, like empty fields.

2. Step 2: Evaluate each option

   Test input with empty fields to check validation tests empty input, a common error source. Others are unrelated or random.

3. Final Answer:

   Test input with empty fields to check validation -> Option D

4. Quick Check:

   Empty input tests = Error guessing [OK]

Hint: Look for tests targeting likely error spots [OK]

Common Mistakes:

• Choosing tests unrelated to error conditions
• Confusing UI checks with error guessing
• Selecting random or unplanned tests

3. Given this scenario: A login form accepts username and password. Which input is best for error guessing?

medium

A. Username: 'admin', Password: '1234'

B. Username: '', Password: ''

C. Username: 'user1', Password: 'password'

D. Username: 'test', Password: 'test123'

Solution

1. Step 1: Identify inputs likely to cause errors

   Empty username and password fields often cause validation errors.

2. Step 2: Compare options for error likelihood

   Username: '', Password: '' uses empty inputs, which is a common error guess. Others are normal inputs.

3. Final Answer:

   Username: '', Password: '' -> Option B

4. Quick Check:

   Empty inputs = Common error guess [OK]

Hint: Empty or invalid inputs are classic error guesses [OK]

Common Mistakes:

• Choosing normal valid inputs
• Ignoring empty or boundary inputs
• Assuming random inputs are best

4. You wrote an error guessing test for a form but it never finds bugs. What is the most likely problem?

medium

A. You guessed errors in unlikely places

B. You wrote too many test cases

C. You automated all tests

D. You tested only the UI colors

Solution

1. Step 1: Understand error guessing effectiveness

   Error guessing works best when testers guess likely error spots based on experience.

2. Step 2: Analyze why tests fail to find bugs

   If guesses are in unlikely places, bugs won't be found. Other options don't explain this well.

3. Final Answer:

   You guessed errors in unlikely places -> Option A

4. Quick Check:

   Wrong guess spots = No bugs found [OK]

Hint: Guess where errors usually happen, not random places [OK]

Common Mistakes:

• Thinking more tests always find more bugs
• Believing automation replaces error guessing
• Focusing on UI style instead of error sources

5. You want to use error guessing to test a calculator app. Which combination of inputs is best to find errors?

hard

A. Very large numbers, zero, and dividing by zero

B. Random letters instead of numbers

C. Only positive integers

D. Normal numbers like 5 + 3, 10 - 2

Solution

1. Step 1: Identify error-prone inputs for calculator

   Calculators often fail with large numbers, zero, or division by zero.

2. Step 2: Evaluate options for error guessing effectiveness

   Very large numbers, zero, and dividing by zero targets these error-prone inputs, while others do not or are invalid inputs.

3. Final Answer:

   Very large numbers, zero, and dividing by zero -> Option A

4. Quick Check:

   Edge and invalid inputs = Best error guesses [OK]

Hint: Test edge cases and invalid inputs for errors [OK]

Common Mistakes:

• Testing only normal inputs
• Ignoring division by zero errors
• Using completely invalid inputs without context