pytest.raises context manager - Build an Automation Script

Verify that dividing by zero raises a ZeroDivisionError

Preconditions (2)

Step 1: Write a function that divides two numbers

Step 2: Call the function with divisor as zero inside pytest.raises context manager

Step 3: Check that ZeroDivisionError is raised

✅ Expected Result: Test passes confirming ZeroDivisionError is raised when dividing by zero

Automation Requirements - pytest

Assertions Needed:

Verify ZeroDivisionError is raised when divisor is zero

Best Practices:

Use pytest.raises as a context manager

Keep test function simple and focused

Do not catch exceptions manually inside the test

Automated Solution

PyTest

import pytest

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

def test_divide_by_zero_raises():
    with pytest.raises(ZeroDivisionError):
        divide(10, 0)

The divide function simply divides two numbers.

The test test_divide_by_zero_raises uses pytest.raises as a context manager to check that calling divide(10, 0) raises a ZeroDivisionError.

This is the correct way to test exceptions in pytest because it clearly shows the expected error and keeps the test clean.

Common Mistakes - 3 Pitfalls

Catching the exception manually with try-except inside the test

Not specifying the exception type in pytest.raises

Placing code outside the pytest.raises block that raises the exception

Bonus Challenge

Now add data-driven testing with 3 different pairs of inputs where division by zero should raise ZeroDivisionError

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