Coverage thresholds in PyTest - Build an Automation Script

Verify code coverage meets minimum threshold using pytest

Preconditions (2)

Step 1: Run pytest with coverage enabled using the command: pytest --cov=your_package_name

Step 2: Check the coverage report summary in the console output

Step 3: Verify that the total coverage percentage is at least 80%

✅ Expected Result: The coverage report shows total coverage percentage of 80% or higher, indicating tests cover at least 80% of the code.

Automation Requirements - pytest

Assertions Needed:

Assert that coverage percentage is >= 80%

Best Practices:

Use pytest-cov plugin for coverage measurement

Use pytest hooks or coverage API to programmatically check coverage

Fail the test if coverage threshold is not met

Automated Solution

PyTest

import pytest
from coverage import Coverage

# This test runs coverage programmatically and asserts threshold

def test_coverage_threshold():
    cov = Coverage(source=["your_package_name"])
    cov.start()

    # Import the module to run its code coverage
    import your_package_name

    # Run tests programmatically using pytest main
    result = pytest.main(["tests/"])

    cov.stop()
    cov.save()

    total_coverage = cov.report(show_missing=False)

    assert total_coverage >= 80, f"Coverage {total_coverage}% is below threshold of 80%"

This test uses the coverage module to start coverage measurement on the target package. It then runs all tests in the tests/ directory using pytest.main(). After tests finish, it stops coverage and reports the total coverage percentage. The assertion checks if coverage is at least 80%. If not, the test fails with a clear message.

This approach automates coverage threshold verification inside a test, so coverage enforcement is part of the test suite.

Common Mistakes - 3 Pitfalls

Running pytest with coverage from command line but not asserting coverage in code

Hardcoding coverage threshold in multiple places

Not stopping or saving coverage before reporting

Bonus Challenge

Now add data-driven testing to verify coverage thresholds for multiple packages with different minimum percentages

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