पैरामीटराइज़ेशन और परीक्षण कवरेज

import pytest

@pytest.mark.parametrize("a,b,expected", [
    (1, 2, 3),
    (0, 0, 0),
    (-1, 1, 0),
    (10, -5, 5),
])
def test_add(a, b, expected):
    assert a + b == expected

import pytest

@pytest.mark.parametrize("n", [1, 2, 3, 4, 5])
def test_positive(n):
    assert n > 0

import pytest

@pytest.mark.parametrize("value,result", [
    (2, True),
    (3, False),
], ids=["even", "odd"])
def test_is_even(value, result):
    assert (value % 2 == 0) == result

import pytest

@pytest.mark.parametrize("x", [1, 2])
@pytest.mark.parametrize("y", [10, 20])
def test_product(x, y):
    assert x * y > 0   # 4 test cases: (1,10),(1,20),(2,10),(2,20)

# pip install pytest-cov

# Basic usage:
# pytest --cov=mypackage

# HTML report:
# pytest --cov=mypackage --cov-report=html

# Name          Stmts   Miss  Cover
# -------       -----   ----  -----
# mypackage/utils.py  20       3    85%
#
# Missing: lines 45, 67, 88

# pytest --cov=mypackage --cov-branch

def is_positive(n):
    if n > 0:        # branch 1: True
        return True
    return False     # branch 2: False

# pytest --cov=mypackage --cov-fail-under=80
# FAIL Required test coverage of 80% not reached. Total: 72%

# .coveragerc
[run]
omit =
    */migrations/*
    */tests/*
    setup.py

[report]
exclude_lines =
    pragma: no cover
    if TYPE_CHECKING:

# A covered but useless test:
def test_nothing():
    is_positive(5)   # no assert — 100% coverage, zero confidence

# A meaningful test:
def test_positive():
    assert is_positive(5) is True
    assert is_positive(-1) is False

import pytest

@pytest.mark.parametrize("n,expected", [
    (5, True), (-1, False), (0, False)
])
def test_is_positive(n, expected):
    assert is_positive(n) == expected