使用自定义目录收集器

Using a custom directory collector

默认情况下,pytest 使用 pytest.Package 收集包含 __init__.py 文件的目录,使用 pytest.Dir 收集其他目录。如果你想自定义如何收集一个目录,可以编写自己的 pytest.Directory 收集器,并使用 pytest_collect_directory 将其挂接上。

目录清单文件的基本示例

A basic example for a directory manifest file

假设你想在每个目录的基础上自定义收集方式。这里是一个示例 conftest.py 插件,允许目录包含一个 manifest.json 文件,该文件定义了该目录的收集方式。在这个例子中,仅支持简单的文件列表,然而你可以想象添加其他键,例如排除项和通配符。

# content of conftest.py
from __future__ import annotations

import json

import pytest


class ManifestDirectory(pytest.Directory):
    def collect(self):
        # The standard pytest behavior is to loop over all `test_*.py` files and
        # call `pytest_collect_file` on each file. This collector instead reads
        # the `manifest.json` file and only calls `pytest_collect_file` for the
        # files defined there.
        manifest_path = self.path / "manifest.json"
        manifest = json.loads(manifest_path.read_text(encoding="utf-8"))
        ihook = self.ihook
        for file in manifest["files"]:
            yield from ihook.pytest_collect_file(
                file_path=self.path / file, parent=self
            )


@pytest.hookimpl
def pytest_collect_directory(path, parent):
    # Use our custom collector for directories containing a `manifest.json` file.
    if path.joinpath("manifest.json").is_file():
        return ManifestDirectory.from_parent(parent=parent, path=path)
    # Otherwise fallback to the standard behavior.
    return None

你可以创建一个 manifest.json 文件和一些测试文件:

{
    "files": [
        "test_first.py",
        "test_second.py"
    ]
}
# content of test_first.py
from __future__ import annotations


def test_1():
    pass
# content of test_second.py
from __future__ import annotations


def test_2():
    pass
# content of test_third.py
from __future__ import annotations


def test_3():
    pass

现在你可以执行测试规范:

customdirectory $ pytest
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-8.x.y, pluggy-1.x.y
rootdir: /home/sweet/project/customdirectory
configfile: pytest.ini
collected 2 items

tests/test_first.py .                                                [ 50%]
tests/test_second.py .                                               [100%]

============================ 2 passed in 0.12s =============================

注意 test_third.py 没有被执行,因为它没有在清单中列出。

你可以验证你的自定义收集器出现在收集树中:

customdirectory $ pytest --collect-only
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-8.x.y, pluggy-1.x.y
rootdir: /home/sweet/project/customdirectory
configfile: pytest.ini
collected 2 items

<Dir customdirectory>
<ManifestDirectory tests>
    <Module test_first.py>
    <Function test_1>
    <Module test_second.py>
    <Function test_2>

======================== 2 tests collected in 0.12s ========================