62 lines
1.9 KiB
ReStructuredText
62 lines
1.9 KiB
ReStructuredText
Known limitations
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=================
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pytest-xdist has some limitations that may be supported in pytest but can't be supported in pytest-xdist.
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Order and amount of test must be consistent
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-------------------------------------------
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Is is not possible to have tests that differ in order or their amount across workers.
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This is especially true with ``pytest.mark.parametrize``, when values are produced with sets or other unordered iterables/generators.
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Example:
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.. code-block:: python
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import pytest
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@pytest.mark.parametrize("param", {"a","b"})
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def test_pytest_parametrize_unordered(param):
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pass
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In the example above, the fact that ``set`` are not necessarily ordered can cause different workers
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to collect tests in different order, which will throw an error.
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Workarounds
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~~~~~~~~~~~
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A solution to this is to guarantee that the parametrized values have the same order.
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Some solutions:
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* Convert your sequence to a ``list``.
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.. code-block:: python
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import pytest
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@pytest.mark.parametrize("param", ["a", "b"])
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def test_pytest_parametrize_unordered(param):
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pass
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* Sort your sequence, guaranteeing order.
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.. code-block:: python
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import pytest
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@pytest.mark.parametrize("param", sorted({"a", "b"}))
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def test_pytest_parametrize_unordered(param):
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pass
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Output (stdout and stderr) from workers
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---------------------------------------
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The ``-s``/``--capture=no`` option is meant to disable pytest capture, so users can then see stdout and stderr output in the terminal from tests and application code in real time.
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However this option does not work with ``pytest-xdist`` because `execnet <https://github.com/pytest-dev/execnet>`__ the underlying library used for communication between master and workers, does not support transferring stdout/stderr from workers.
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Currenlty there are no plans ot support this in ``pytest-xdist``.
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