Test modules in PyTest - Framework Patterns

Framework Mode - Test modules

Folder Structure of a Pytest Project

project-root/
├── tests/
│   ├── test_login.py
│   ├── test_shopping_cart.py
│   ├── test_checkout.py
│   └── __init__.py
├── src/
│   └── app_code.py
├── conftest.py
├── pytest.ini
└── requirements.txt
  

Test Framework Layers in Pytest

• Test Modules: Python files starting with test_ or ending with _test.py inside the tests/ folder. Each module groups related test functions.
• Test Functions: Individual test cases inside test modules. Named starting with test_.
• Fixtures: Setup and teardown code shared across tests, defined in conftest.py or test modules.
• Application Code: The actual code under test, usually in src/ or similar folder.
• Configuration: Files like pytest.ini to configure pytest behavior.

Configuration Patterns for Pytest Test Modules

• pytest.ini: Central place to configure test discovery, markers, and options.
• conftest.py: Define fixtures and hooks shared across test modules.
• Environment Variables: Use os.environ or python-dotenv to manage environment-specific data like URLs or credentials.
• Command Line Options: Add custom options in conftest.py to select browsers, environments, or test groups.

Test Reporting and CI/CD Integration

• Built-in pytest reports: Console output shows passed/failed/skipped tests.
• Plugins: Use plugins like pytest-html for HTML reports or pytest-cov for coverage reports.
• CI/CD Integration: Run tests automatically in pipelines (GitHub Actions, Jenkins) using pytest commands.
• Artifacts: Save reports and logs as pipeline artifacts for review.

Best Practices for Pytest Test Modules

• Keep test modules focused on one feature or area for clarity.
• Name test modules and functions clearly to describe what they test.
• Use fixtures in conftest.py to avoid repeating setup code across modules.
• Organize tests in the tests/ folder separate from application code.
• Use markers to group or skip tests easily during runs.

Self Check

Where would you add a new test module for user profile features in this framework structure?

Key Result

Pytest test modules are organized Python files in the tests/ folder grouping related test functions for clear, maintainable automated testing.

Practice

1. What is the correct way to name a Python file so that pytest recognizes it as a test module?

easy

A. The file name can be anything as long as it contains tests.

B. The file name should start with check_.

C. The file name should be pytest_module.py.

D. The file name should start with test_ or end with _test.py.

Solution

1. Step 1: Understand pytest file naming conventions

   pytest automatically discovers test files if their names start with test_ or end with _test.py.

2. Step 2: Evaluate each option

   Only The file name should start with test_ or end with _test.py. matches the correct naming pattern for pytest to find test modules automatically.

3. Final Answer:

   The file name should start with test_ or end with _test.py. -> Option D

4. Quick Check:

   pytest test file naming = start with test_ or end with _test.py [OK]

Hint: Remember test files start with test_ or end with _test.py [OK]

Common Mistakes:

• Assuming any file with tests is recognized
• Using incorrect prefixes like check_
• Naming files without .py extension

2. Which of the following is the correct syntax for a test function inside a pytest test module?

easy

A. def test_function():

B. def check_function():

C. def function_test():

D. def testing_function():

Solution

1. Step 1: Recall pytest test function naming rules

   pytest runs functions that start with test_ automatically as tests.

2. Step 2: Match options with naming rule

   Only def test_function(): defines a function starting with test_, so pytest will recognize it as a test.

3. Final Answer:

   def test_function(): -> Option A

4. Quick Check:

   Test functions start with test_ [OK]

Hint: Test functions must start with test_ to run automatically [OK]

Common Mistakes:

• Naming test functions without test_ prefix
• Using other prefixes like check_ or testing_
• Forgetting to define functions with def

3. Given the following test module test_sample.py with these functions:

def test_add():
    assert 1 + 1 == 2

def add():
    return 1 + 1

def test_subtract():
    assert 2 - 1 == 1

Which functions will pytest run as tests?

medium

A. All three functions

B. Only add

C. test_add and test_subtract

D. Only test_add

Solution

1. Step 1: Identify pytest test function naming

   pytest runs functions starting with test_ automatically as tests.

2. Step 2: Check each function name

   test_add and test_subtract start with test_, so pytest runs them. add does not start with test_, so it is ignored.

3. Final Answer:

   test_add and test_subtract -> Option C

4. Quick Check:

   Functions starting with test_ run as tests [OK]

Hint: Only functions starting with test_ run as tests [OK]

Common Mistakes:

• Thinking all functions in test file run as tests
• Confusing helper functions with test functions
• Ignoring function name prefixes

4. You have a test module named test_math.py with this code:

def test_multiply():
    assert 2 * 3 == 5

When you run pytest, what will happen?

medium

A. The test will fail because the assertion is incorrect.

B. pytest will not find any tests to run.

C. pytest will skip the test because of a syntax error.

D. The test will pass because 2 * 3 equals 6.

Solution

1. Step 1: Analyze the assertion in test_multiply

   The assertion checks if 2 * 3 == 5, which is false because 2 * 3 equals 6.

2. Step 2: Understand pytest test result

   pytest runs the test and finds the assertion false, so the test fails.

3. Final Answer:

   The test will fail because the assertion is incorrect. -> Option A

4. Quick Check:

   False assertion causes test failure [OK]

Hint: Check if assertion condition is true or false [OK]

Common Mistakes:

• Assuming test passes despite wrong assertion
• Confusing syntax errors with assertion failures
• Thinking pytest skips failing tests

5. You want to organize tests for a calculator app. You create two files: test_add.py and test_subtract.py. Each file has multiple test functions starting with test_. How does pytest handle these test modules when you run pytest in the folder?

hard

A. pytest requires you to specify each test module to run tests.

B. pytest runs all test functions from both modules automatically.

C. pytest runs only tests from the first module alphabetically.

D. pytest runs tests only if you import modules manually.

Solution

1. Step 1: Understand pytest test discovery

   pytest automatically finds all test modules named with test_ prefix and runs all test functions inside them.

2. Step 2: Apply to multiple test modules

   When running pytest in the folder, it collects tests from both test_add.py and test_subtract.py and runs all test functions starting with test_.

3. Final Answer:

   pytest runs all test functions from both modules automatically. -> Option B

4. Quick Check:

   pytest auto-discovers all test modules and functions [OK]

Hint: pytest runs all test_ modules and functions in folder automatically [OK]

Common Mistakes:

• Thinking pytest runs only one module at a time
• Believing manual imports are needed for tests
• Assuming tests must be specified explicitly