Synchronous Unit Testing¶

Overview¶

This guide dives into the sync_unit_testing sample, showcasing Pynenc’s support for synchronous unit testing. This feature is crucial for developers looking to test their tasks in isolation without the need for an asynchronous task runner. By leveraging Python’s unittest framework and Pynenc’s synchronous execution mode, this example demonstrates how to effectively unit test tasks to ensure reliability and correctness.

The full source code for this demonstration is available on GitHub: sync_unit_testing.

Scenario¶

The sync_unit_testing scenario is designed to illustrate how tasks defined with Pynenc can be tested synchronously, simplifying the testing process by running tasks immediately and sequentially during the test execution. This approach is particularly useful for testing the logic of tasks without involving the complexity of asynchronous execution.

Setup¶

Requirements¶

Python 3.11 or higher.
Pynenc library installed.

Project Files¶

tasks.py: Contains a simple add task definition using Pynenc, suitable for demonstrating unit testing.
test_add.py: Includes unit tests for the add task, showcasing two methods for enforcing synchronous execution within tests.

Demonstration¶

Defining a Task¶

The add task defined in tasks.py is a basic example of a task that can be used for unit testing:

from pynenc import Pynenc

app = Pynenc()

@app.task
def add(x: int, y: int) -> int:
    add.logger.info(f"{add.task_id=} Adding {x} + {y}")
    return x + y

This task simply adds two numbers and logs the operation, making it ideal for testing the setup and execution of tasks with Pynenc.

Testing Tasks Synchronously¶

The unit tests in test_add.py demonstrate two approaches to testing tasks synchronously:

Direct Configuration¶

The TestAddTaskConf class shows how to directly set the Pynenc configuration to force synchronous task execution:

class TestAddTaskConf(unittest.TestCase):
    def setUp(self) -> None:
        tasks.app.conf.dev_mode_force_sync_tasks = True

    def test_add(self) -> None:
        invocation = tasks.add(1, 2)
        self.assertEqual(invocation.result, 3)

Environment Variable Patching¶

The TestAddTaskEnviron class uses unittest.mock.patch.dict to simulate setting an environment variable that forces synchronous execution:

class TestAddTaskEnviron(unittest.TestCase):
    def setUp(self) -> None:
        self.patcher = patch.dict(os.environ, {"PYNENC__DEV_MODE_FORCE_SYNC_TASKS": "True"})
        self.patcher.start()

    def tearDown(self) -> None:
        self.patcher.stop()

    def test_add(self) -> None:
        invocation = tasks.add(1, 2)
        self.assertEqual(invocation.result, 3)

Both methods ensure that tasks are executed synchronously, facilitating isolated unit tests without the need for an external task runner.

Conclusion¶

The sync_unit_testing sample provides an essential foundation for writing and executing unit tests for tasks managed by Pynenc. By highlighting methods for synchronous task execution within tests, it empowers developers to conduct thorough and reliable testing of their task logic in isolation, ensuring the robustness and correctness of their applications.