Arrange-Act-Assert pattern in PyTest - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Identify the output of a pytest test using Arrange-Act-Assert

What will be the result of running this pytest test function?

PyTest

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

def test_add():
    # Arrange
    x = 5
    y = 3
    # Act
    result = add(x, y)
    # Assert
    assert result == 8

A Test passes successfully

B TypeError during test execution

C SyntaxError during test execution

D Test fails with AssertionError

💡 Hint

Check if the assertion matches the expected sum of x and y.

The test arranges inputs x=5 and y=3, acts by calling add(x, y), and asserts the result equals 8. Since 5 + 3 is 8, the assertion passes and the test succeeds.

❓ assertion

intermediate

Choose the correct assertion for Arrange-Act-Assert pattern

Given the following test code snippet, which assertion correctly verifies the output?

PyTest

def multiply(a, b):
    return a * b

def test_multiply():
    # Arrange
    a = 4
    b = 6
    # Act
    output = multiply(a, b)
    # Assert
    # Which assertion is correct here?

A assert output < 20

B assert output != 24

C assert output > 30

D assert output == 24

💡 Hint

Multiply 4 by 6 and check the expected result.

4 multiplied by 6 equals 24, so the assertion should check output == 24 to pass.

🔧 Debug

advanced

Find the bug in this Arrange-Act-Assert pytest test

This test is supposed to check if the function returns the square of a number. What is the bug causing the test to fail?

PyTest

def square(n):
    return n * n

def test_square():
    # Arrange
    num = 7
    # Act
    result = square(num)
    # Assert
    assert result == 42

A The function square is not defined correctly

B The assertion expects 42 but 7 squared is 49

C The variable num is not assigned properly

D The test is missing the Act step

💡 Hint

Calculate 7 squared and compare with the assertion value.

7 squared is 49, but the assertion expects 42, causing the test to fail.

❓ framework

advanced

Identify the correct Arrange-Act-Assert structure in pytest

Which of the following pytest test functions correctly follows the Arrange-Act-Assert pattern?

A

def test_func():
    x = 10
    y = 20
    result = x + y
    assert result == 30

B

def test_func():
    assert 10 + 20 == 30
    x = 10
    y = 20
    result = x + y

C

def test_func():
    result = 10 + 20
    x = 10
    y = 20
    assert result == 30

D

def test_func():
    x = 10
    assert x == 10
    y = 20
    result = x + y

💡 Hint

Arrange means setting up variables first, then Act, then Assert last.

Option A arranges variables x and y, acts by adding them, then asserts the result. Others mix steps or assert too early.

🧠 Conceptual

expert

Why is the Arrange-Act-Assert pattern important in testing?

Select the best explanation for the importance of the Arrange-Act-Assert pattern in writing tests.

A It allows skipping the assertion step if the test runs without errors.

B It enforces using only one assertion per test function.

C It organizes tests clearly into setup, execution, and verification steps, improving readability and maintenance.

D It requires tests to run faster by combining all steps into one line.

💡 Hint

Think about how clear structure helps when reading or fixing tests later.

Arrange-Act-Assert separates setup, action, and checking, making tests easier to understand and maintain.