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jbranchaud
42 lines
1.7 KiB
Markdown
42 lines
1.7 KiB
Markdown
# Look Inside Pytest tmp_path
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In [Isolate and Debug File Side-Effects with Pytest
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`tmp_path`](https://www.visualmode.dev/isolate-and-debug-file-side-effects-with-pytest-tmp-path),
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I wrote about how I use
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[`tmp_path`](https://docs.pytest.org/en/stable/reference/reference.html#std-fixture-tmp_path)
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in a Pytest fixture to test [my `py-vmt` CLI](https://github.com/jbranchaud/py-vmt). During testing of the CLI interface
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via [`click`'s testing utilities](https://click.palletsprojects.com/en/stable/testing/), `vmt` creates,
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modifies, and reads from files. Isolating that behavior with the `tmp_path`
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fixture is useful because it prevents individual test cases from conflicting
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with one another.
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Here is what the fixture looks like at the top of my test file:
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```python
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# auto fixture for all test cases that monkeypatches the platform dirs to a tmp
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# path so that test side-effects don't persist between runs
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@pytest.fixture(autouse=True)
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def use_tmp_platform_dirs(tmp_path, monkeypatch):
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data_dir = tmp_path / "data"
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config_dir = tmp_path / "config"
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data_dir.mkdir()
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config_dir.mkdir()
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monkeypatch.setattr(CliContext, "get_data_dir", staticmethod(lambda: data_dir))
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monkeypatch.setattr(CliContext, "get_config_dir", staticmethod(lambda: config_dir))
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```
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The root of the temp directory is located at `tempfile.gettempdir()` and the
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directories from there are organized with this structure:
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```
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{temproot}/pytest-of-{user}/pytest-{num}/{testname}/
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```
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So, in the case of `vmt`, I can find the `config` and `data` dirs for a specific
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test run here:
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```bash
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❯ ls /var/folders/zc/q6gnvbgx6kq77828jn38716r0000gn/T/pytest-of-lastword/pytest-2/test_start_status_stop_flow0
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config data
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```
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