Boundary value analysis in Testing Fundamentals - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Identify boundary values for input range

Consider a function that accepts an integer input between 10 and 50 inclusive. Which set correctly represents the boundary values for testing?

A 9, 10, 11, 49, 50, 51

B 10, 20, 30, 40, 50

C 11, 25, 49

D 9, 15, 35, 51

💡 Hint

Boundary values include the edges and just outside the edges of the input range.

Boundary value analysis tests the edges of input ranges. For 10 to 50 inclusive, test values just below 10 (9), at 10, just above 10 (11), just below 50 (49), at 50, and just above 50 (51).

❓ Predict Output

intermediate

Output of boundary test function

What is the output of the following Python function when called with input 100?

Testing Fundamentals

def test_input(x):
    if x < 1 or x > 100:
        return "Invalid"
    elif x == 1 or x == 100:
        return "Boundary"
    else:
        return "Normal"

result = test_input(100)
print(result)

A Error

B Normal

C Boundary

D Invalid

💡 Hint

Check the conditions for input equal to 100.

The function returns "Boundary" if input is exactly 1 or 100. Since input is 100, output is "Boundary".

❓ assertion

advanced

Assertion for boundary value test

Which assertion correctly tests that a function validate_age returns true for the boundary age 18?

Testing Fundamentals

def validate_age(age):
    return 18 <= age <= 65

A assert validate_age(18) == False

B assert validate_age(18) is False

C assert validate_age(18) != True

D assert validate_age(18) == True

💡 Hint

Check the function logic for age 18.

The function returns true if age is between 18 and 65 inclusive. So for age 18, it returns true. The assertion must check for true.

🔧 Debug

advanced

Find the boundary test bug

Given this test code for a function is_valid_score that accepts scores 0 to 100 inclusive, which option shows the bug causing a boundary test to fail?

Testing Fundamentals

def is_valid_score(score):
    return 0 <= score < 100

assert is_valid_score(100) == True

A The function excludes 100, so assert fails because 100 is not valid

B The function includes 100, so assert fails due to wrong logic

C The assert syntax is wrong, causing failure

D The function accepts negative scores, causing failure

💡 Hint

Check the comparison operators in the function.

The function uses < 100, so 100 is excluded. The assert expects true for 100, causing failure.

❓ framework

expert

Design boundary tests in pytest

Which pytest test function correctly tests the boundary values for a function check_temperature that accepts temperatures from -20 to 50 inclusive?

Testing Fundamentals

def check_temperature(temp):
    return -20 <= temp <= 50

A

import pytest
@pytest.mark.parametrize('temp', [-20, 0, 50])
def test_temp(temp):
    assert check_temperature(temp) == True

B

import pytest
@pytest.mark.parametrize('temp', [-21, -20, -19, 49, 50, 51])
def test_temp(temp):
    expected = temp >= -20 and temp <= 50
    assert check_temperature(temp) == expected

C

import pytest
@pytest.mark.parametrize('temp', [-21, 51])
def test_temp(temp):
    assert check_temperature(temp) == False

D

import pytest
def test_temp():
    assert check_temperature(-20) and check_temperature(50)

💡 Hint

Boundary tests include just outside and on the edges of the valid range.

Option B tests values just below, at, just above boundaries and asserts expected results correctly. Others miss some boundary or do not test both valid and invalid cases.