How do I run tests randomly using pytest?

To run tests randomly using Pytest, you'll typically use the pytest-randomly plugin. Here's how to install and use it:

1. Installation:

First, install the pytest-randomly plugin using pip:

pip install pytest-randomly

2. Basic Usage:

- After installing, simply run your tests as usual with pytest. The tests will now execute in a random order by default.

3. Specific Options:

- Specifying Seed: If you want to reproduce a specific random order, you can use the --randomly-seed option followed by an integer value:

pytest --randomly-seed=12345

This will execute the tests in a random order based on the seed 12345. Use this seed to reproduce the same test execution order later.

- Show Seed Output: The plugin displays a seed value at the beginning of every test run. You can use that value if you want to re-run the same test order again.

4. Configuration in `pytest.ini`:

- You can also configure a default random seed in the pytest.ini file or other supported configuration files to avoid needing to specify --randomly-seed on the command line every time. Here is an example:

[pytest]
randomly_seed = 42

- If you use this configuration, tests will be executed in random order using seed 42 as default, unless overridden by the command line.

5. Benefits of Random Testing:

- Identify Interdependencies: Random test order can help you identify dependencies between tests that you might not have otherwise noticed.

- Reveal Subtle Bugs: By randomizing test execution, you can sometimes uncover bugs that only appear in specific execution sequences.

By using the pytest-randomly plugin, you can enhance your testing process and uncover potential problems in your code more effectively.

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