Statement coverage in Testing Fundamentals - Build an Automation Script

Automate statement coverage test for a simple function

Preconditions (2)

Step 1: Create a Python function named calculate_discount that takes a price and a boolean is_member

Step 2: If is_member is True, apply 10% discount to price, else no discount

Step 3: Write test cases to call calculate_discount with both True and False for is_member

Step 4: Run tests and verify all statements in calculate_discount are executed

✅ Expected Result: All statements in calculate_discount function are executed and tests pass

Automation Requirements - pytest

Assertions Needed:

Assert discounted price is correct for member

Assert price remains same for non-member

Best Practices:

Use clear test function names

Test all branches to cover all statements

Keep tests independent and simple

Automated Solution

Testing Fundamentals

def calculate_discount(price: float, is_member: bool) -> float:
    if is_member:
        return price * 0.9
    else:
        return price

import pytest

def test_calculate_discount_member():
    assert calculate_discount(100, True) == 90

def test_calculate_discount_non_member():
    assert calculate_discount(100, False) == 100

The calculate_discount function applies a 10% discount if the user is a member. The tests test_calculate_discount_member and test_calculate_discount_non_member call the function with both possible values of is_member. This ensures every statement in the function runs at least once, achieving full statement coverage. Assertions check the returned price is correct. Using pytest allows easy running and reporting of test results.

Common Mistakes - 3 Pitfalls

Testing only one branch of the if statement

Using print statements instead of assertions

Combining multiple test cases into one

Bonus Challenge

Now add data-driven testing with 3 different prices and both member statuses

Show Hint