Test modules in PyTest - Build an Automation Script

Verify pytest test module execution and results

Preconditions (2)

Step 1: Open terminal or command prompt

Step 2: Navigate to the directory containing test_sample.py

Step 3: Run the command 'pytest test_sample.py'

Step 4: Observe the test execution output

Step 5: Verify that all test functions in the module run and their results are displayed

✅ Expected Result: pytest runs all tests in test_sample.py and shows a summary with pass/fail status for each test

Automation Requirements - pytest

Assertions Needed:

Verify that test functions execute without errors

Verify that pytest output includes test names and pass/fail status

Best Practices:

Use descriptive test function names starting with 'test_'

Keep tests independent and isolated

Use assert statements for validation

Organize tests in modules named test_*.py

Automated Solution

PyTest

import subprocess
import sys
import re

def test_pytest_module_execution():
    # Run pytest on the test_sample.py module
    result = subprocess.run([sys.executable, '-m', 'pytest', 'test_sample.py', '--tb=short', '-q'], capture_output=True, text=True)
    output = result.stdout
    # Check pytest exited with code 0 (success)
    assert result.returncode == 0, f"pytest exited with code {result.returncode}"
    # Check output contains test function names and pass status
    assert re.search(r'test_function_one', output), "test_function_one not found in output"
    assert re.search(r'test_function_two', output), "test_function_two not found in output"
    assert re.search(r'\d+ passed', output), "No tests passed message found"

This test script runs pytest on the module test_sample.py using Python's subprocess module. It captures the output and return code.

We assert that pytest exits with code 0, meaning all tests passed. Then we check the output text to confirm the test function names appear and that the summary shows tests passed.

This approach verifies that the test module runs correctly and pytest reports results as expected.

Common Mistakes - 3 Pitfalls

Not capturing pytest output for verification

Using print statements instead of assert for validation

Running pytest without specifying the test module

Bonus Challenge

Now add data-driven testing with 3 different inputs for one test function in the module

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