Python 模擬單元測試和數據庫

Question

當我測試我的代碼中的方法時，我想存根數據庫調用。 我想要它做的就是返回我的價值，但我似乎無法走那么遠。

def loadSummary(appModel):
    stmt = 'Select * from Table'
    for row in appModel.session.query(*t.columnNames()).from_statement(stmt).all():
        t.append(row)
    return t

def test_loadSummary(self):
    appModel = Mock()
    query = appModel.session.query.return_value
    query.from_statment.return_value = ['test1', 'test2']
    expected = loadSummary(appModel)

我收到以下錯誤

for row in appModel.session.query(*t.columnNames()).from_statement(stmt).all():
TypeError: 'Mock' object is not iterable

所以它就像它根本沒有被傳遞到方法中，即使它在 shell 中工作也沒有問題。

>>> appModel.session.query('').from_statment('stmt')
['test1', 'test2']

然后我嘗試使用 mock.patch.object

class MockAppContoller(object):
    def from_from_statement(self, stmt):
        return ['test1', 'test2']

def test_loadSummary(self):
    with mock.patch.object(loadSummary, 'appModel') as mock_appModel:
        mock_appModel.return_value = MockAppContoller()

我收到以下錯誤

2014-04-09 13:20:53,276 root ERROR Code failed with error:
<function loadSummary at 0x0D814AF0> does not have the attribute 'appModel'

我怎樣才能解決這個問題？

Answer 1

您的錯誤似乎在這里：

 query.from_statment.return_value = ['test1', 'test2']

應該：

 query.from_statement.return_value.all.return_value = ['test1', 'test2']

它在 shell 中為您工作，因為您沒有使用相同的代碼

>>> appModel.session.query('').from_statement('stmt')
['test1', 'test2']

如果你真的嘗試過會失敗

>>> appModel.session.query('').from_statment('stmt').all()
['test1', 'test2']

Answer 2

我想出的另一個解決方案是這個，但它不像使用 Mock 那樣整潔

class mockAppModel(object):
    def from_from_statement(self, stmt):       
        t = []
        t.appendRow('row1', 'row2')
        return t

class mockFromStmt(object): #This is the ONE parameter constructor
    def __init__(self):
        self._all = mockAppModel()

    def all(self):  #This is the needed all method
        return self._all.from_from_statement('')

class mockQuery(object): #This is the ONE parameter constructor
    def __init__(self):
        self._from_statement = mockFromStmt()

    def from_statement(self, placeHolder): #This is used to mimic the query.from_statement() call
        return self._from_statement 

class mockSession(object):
    def __init__(self):
        self._query = mockQuery()

    def query(self, *args):  #This is used to mimic the session.query call
        return self._query

class mockAppModel(object):
    def __init__(self):
        self.session = mockSession()