How are parameterized tests implemented in PyTest?.

Parameterized tests in PyTest are implemented using the @pytest.mark.parametrize decorator. It allows running the same test with different sets of input data.

Example:

import pytest

@pytest.mark.parametrize("input,expected", [
    (2, 4),
    (3, 9),
    (4, 16),
])
def test_square(input, expected):
    assert input * input == expected

In this example, the test_square test will be run three times with different values of input and expected. This is convenient for testing a function with various data without duplicating code.