Basic assert statement in PyTest - Build an Automation Script

Verify that the sum of two numbers is correct

Preconditions (2)

Step 1: Create a function that adds two numbers

Step 2: Call the function with inputs 2 and 3

Step 3: Check if the result equals 5 using an assert statement

✅ Expected Result: The assert statement passes confirming the sum is correct

Automation Requirements - pytest

Assertions Needed:

Assert that the sum of 2 and 3 equals 5

Best Practices:

Use clear and simple assert statements

Keep test functions small and focused

Name test functions starting with 'test_'

Automated Solution

PyTest

def add_numbers(a: int, b: int) -> int:
    return a + b

def test_add_numbers():
    result = add_numbers(2, 3)
    assert result == 5, f"Expected 5 but got {result}"

The add_numbers function adds two numbers and returns the result.

The test function test_add_numbers calls this function with 2 and 3, then uses an assert statement to check if the result is 5.

If the result is not 5, the assert will fail and show a clear message.

This simple test shows how to use basic assert statements in pytest.

Common Mistakes - 3 Pitfalls

Not using assert statement and just printing the result

{'mistake': "Using assert with wrong comparison operator like '=' instead of '=='", 'why_bad': "Single '=' is assignment, not comparison, causing syntax errors.", 'correct_approach': "Use '==' to compare values in assert statements."}

Not providing a helpful message in assert

Bonus Challenge

Now add data-driven testing with 3 different pairs of numbers and their expected sums

Show Hint