pytest夹具参数与monkeypatch

Question

我是猴子修补数据库连接类作为夹具。我想要完成的是将一些参数传递给我的猴子修补夹具，因为不同的测试都需要相同的monkeypatch，但返回值不同。

@pytest.fixture 
def data(): 
    now = datetime.datetime.now() 
    data = Data(now) 
    return data 

@pytest.fixture 
def patch_db(monkeypatch): 
    class FakeDbConnection: 
     def __init__(*args, **kwargs): 
      pass 

     def fetchall(self): 
      return [1,2,3] 

    monkeypatch.setattr(DbConnection, 'execute', FakeDbConnection) 


def test_get_somevalue(patch_db, data): 
    userids = data.get_userids() 
    assert userids == [1,2,3] 

def test_get_something_else(patch_db, data): 
    userids = data.get_userids() 
    assert userids == [6,7,8] 

我遇到的问题是，因为我的fetchall函数只返回[1,2,3]。我想有patch_db夹具采取PARAMS：

@pytest.fixture(scope='module', params=[[1, 2, 3], [4, 5, 6]]) 
def patch_db(monkeypatch, test_values): 
    class FakeDbConnection: 
     def __init__(*args, **kwargs): 
      pass 

     def fetchall(self): 
      return test_values.param 

    monkeypatch.setattr(DbConnection, 'execute', FakeDbConnection) 

，但我得到了以下错误： ScopeMismatch: You tried to access the 'function' scoped fixture 'monkeypatch' with a 'module' scoped request object, involved factories

Answer 1

你不能从module夹具使用function夹具，因为有消息称。

如果更改patch_db的范围function它将运行，但是当你想到这个办法是行不通的，因为test_get_somevalue会收到两个patch_db夹具，一个修补与[1, 2, 3]和其他与[4, 5, 6]。

我建议你添加一个函数FakeDbConnection，让测试设置他们想要返回fetchall的东西。以下是完整的示例：

@pytest.fixture 
def data(): 
    now = datetime.datetime.now() 
    data = Data(now) 
    return data 


@pytest.fixture 
def patch_db(monkeypatch): 
    class FakeDbConnection: 
     def __init__(*args, **kwargs): 
      pass 

     def fetchall(self): 
      return fetch_result.values 

    monkeypatch.setattr(DbConnection, 'execute', FakeDbConnection) 

    class FetchResult: 
     pass 

    fetch_result = FetchResult() 
    fetch_result.values = None 
    return fetch_result 


def test_get_somevalue(patch_db, data): 
    patch_db.values = [1,2,3] 
    userids = data.get_userids() 
    assert userids == [1,2,3] 


def test_get_something_else(patch_db, data): 
    patch_db.values = [6,7,8] 
    userids = data.get_userids() 
    assert userids == [6,7,8]