Session-scoped temporary directories in pytest#

I habitually use the tmpdir fixture in pytest to get a temporary directory that will be cleaned up after each test, but that doesn’t work with scope="session" - which can be used to ensure an expensive fixture is run only once per test session and the generated content is used for multiple tests.

To get a temporary directory that works with scope="session", use the tmp_path_factory built-in pytest fixture like this:

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import pytest
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@pytest.fixture(scope="session")
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def template_dir(tmp_path_factory):
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    template_dir = tmp_path_factory.mktemp("page-templates")
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    pages_dir = template_dir / "pages"
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    pages_dir.mkdir()
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    (pages_dir / "about.html").write_text("ABOUT!", "utf-8")
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    (pages_dir / "request.html").write_text("request", "utf-8")
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    return template_dir
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def test_about(template_dir):
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    assert "ABOUT!" == (template_dir / "pages" / "about.html").read_text()
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def test_request(template_dir):
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    assert "request" == (template_dir / "pages" / "request.html").read_text()

Example: https://github.com/simonw/datasette/blob/1b7b66c465e44025ec73421bd69752e42f108321/tests/test_custom_pages.py#L16-L45