pytest模拟本地对象实例在模拟对象中

Question

问题

模拟并对无法从包含对象访问的本地实例对象进行断言。

最小示例

executor是要模拟的类。

class Executor:    
    def execute(self, func, *args):
        func(*args)

模拟executor

import pytest
@pytest.fixture
def executor(mocker):
    mocker.patch('executor.Executor.execute')
    return Executor()

testing executor.execute立即调用。

def test_execute(executor):
    func = lambda x: x**2
    executor.execute(func, 7)
    Executor.execute.assert_called_once_with(func, 7)

    # this fails -- how to test a situation where one doesn't have access to the lambda
    # func2 = lambda y:y**2
    # Executor.execute.assert_called_once_with(func2, 7)

更普遍地

def test_execute_with_complex_args(executor):
    def somefunc(x, y):
        x.increment(y)
    class SomeObj:
        x=30
        def increment(self, y):
            self.x += y
 
    obj = SomeObj()
    executor.execute(somefunc, obj, 7)
    Executor.execute.assert_called_once()

    # this is assuming we have access to somefunc and obj instances
    Executor.execute.assert_called_once_with(somefunc, obj, 7)

    # how to verify that increment was called with arg 7?
    # somefunc and obj are instances that are not accessible? 

为什么这是重要的/对这种圆形测试的需求是什么？

我正在测试使用sqlalchemy的数据库客户端。我想验证查询是通过正确参数执行的。客户端中的一个典型功能看起来像：

def get_job(self, job_id: UUID) -> Job:
        return run_transaction(sessionmaker(bind=self.engine),
                               lambda s: copy(s.query(Job).filter(Job.id == job_id).one()))

sessionmaker和run_transaction是可模拟的，可以进行测试，但我想验证session.query方法被适当地称为。