将参数传递给pytest夹具进行拆卸

Question

问题：清理从测试创建的测试工件。在以下情况下，如何使用pytest固定装置从数据库中删除测试期间创建的单行？ （并非每次运行后都应从表中删除所有内容。否则，可以使用“删除所有行或删除表”）。测试过程中，创建的行的行标识符保存在函数变量中。

是否可以将在测试过程中创建的变量作为参数传递到pytest中的夹具中？无论测试是通过失败还是成功完成，夹具都需要始终运行。在运行测试之前，不会知道行标识符。

用夹具说明的问题

@pytest.fixture()
def clean_up_db_row(row_id):
    yield
    delete_from_db(self.row_id). # code to delete the row based on the id


def test_something_added_to_database(clean_up_db_row):
    row_id = create_db_row()  # function under test
    ...
    assert row_id in db  # test that information added to the database

    # the clean_up_db_row fixture will always run but how will it know about the id variable defined in the function?

如果断言在测试中途失败，则在清理结束时，在测试期间添加的行不会被删除。因为测试停止执行。

问题示例是没有pytest固定装置：

def clean_up_db_row(row_id):
    yield
    delete_from_db(row_id). # code to delete the row based on the id


def test_something_added_to_database():
    row_id = create_db_row()  # function under test
    ...
    assert row_id in db  # test that information added to the database
    clean_up_db_row(row_id)  # this won’t run if there is a failure

没有pytest固定装置的解决方案

def clean_up_db_row(row_id):
    yield
    delete_from_db(row_id). # code to delete the row based on the id

def test_something_added_to_database():
    row_id = create_db_row()  # function under test
    ...
    try:
        assert row_id in db  # test that information added to the database
    except Exception as e:
        raise e
    finally:
        clean_up_db_row(row_id)  # this will always run but doesn’t use a fixture

在类上使用实例变量的潜在解决方案

class TestCaseCleanUp:

    @pytest.fixture(autouse=True)
    def clean_up_db_row(self):
        yield
        delete_from_db(self.row_id). # code to delete the row based on the id


    def test_something_added_to_database(self):
        self.row_id = create_db_row()  # function under test
        ...
        assert self.row_id in db  # test that information added to the database
        # the autouse fixture can use the self.row_id assigned

Answer 1

由灯具产生的对象由跑步者注入到测试环境中。这可以是您想要的任何对象，并且测试可以随意对其进行突变。

这是一种适合您的模式：

@pytest.fixture()
def clean_up_db_rows():
    row_ids = []
    yield row_ids
    for row_id in row_ids:
        delete_from_db(row_id)


def test_something_added_to_database(clean_up_db_rows):
    row_id = create_db_row()  # function under test
    clean_up_db_rows.append(row_id)
    ...
    assert row_id in db  # test that information added to the database