Listing Twelve演示了assert_has_calls()断言。在18~20行,我调用了三个方法,提供了两个输入。然后,我准备了一个期望调用的列表(fooCalls)并把这个列表传入assert_has_calls()(22~23行)。由于列表匹配了方法的调用,断言通过。
Listing Twelve
from mock import Mock, call # The mock specification class Foo(object): _fooValue = 123 def callFoo(self): pass def doFoo(self, argValue): pass # create the mock object mockFoo = Mock(spec = Foo) print mockFoo # returns <Mock spec='Foo' id='507120'> mockFoo.callFoo() mockFoo.doFoo("narf") mockFoo.doFoo("zort") fooCalls = [call.callFoo(), call.doFoo("narf"), call.doFoo("zort")] mockFoo.assert_has_calls(fooCalls) # assert passes fooCalls = [call.callFoo(), call.doFoo("zort"), call.doFoo("narf")] mockFoo.assert_has_calls(fooCalls) # AssertionError: Calls not found. # Expected: [call.callFoo(), call.doFoo('zort'), call.doFoo('narf')] # Actual: [call.callFoo(), call.doFoo('narf'), call.doFoo('zort')] fooCalls = [call.callFoo(), call.doFoo("zort"), call.doFoo("narf")] mockFoo.assert_has_calls(fooCalls, any_order = True) # assert passes |
在第26行,我交换了两个doFoo()调用的顺序。第一个doFoo()获得"zort"的输入,第二个获得了"narf"。如果我传入这个fooCalls到assert_has_calls()(第27行)中,断言失败。但是如果我给参数any_order传入参数True,断言通过。这是因为断言将忽略方法调用的顺序。
Listing Thirteen演示了其他的用法。在fooCalls列表中,我添加了不存在的方法dooFoo()(第22行)。然后我传入fooCalls到assert_has_calls()中(第24行)。断言失败,通知我期望调用的顺序和真实发生的顺序不匹配。如果我给any_order赋值为True(第30行),断言名称dooFoo()作为违规的方法调用。
Listing Thirteen
from mock import Mock, call # The mock specification class Foo(object): _fooValue = 123 def callFoo(self): pass def doFoo(self, argValue): pass # create the mock object mockFoo = Mock(spec = Foo) print mockFoo # returns <Mock spec='Foo' id='507120'> mockFoo.callFoo() mockFoo.doFoo("narf") mockFoo.doFoo("zort") fooCalls = [call.callFoo(), call.dooFoo("narf"), call.doFoo("zort")] mockFoo.assert_has_calls(fooCalls) # AssertionError: Calls not found. # Expected: [call.callFoo(), call.dooFoo('narf'), call.doFoo('zort')] # Actual: [call.callFoo(), call.doFoo('narf'), call.doFoo('zort')] fooCalls = [call.callFoo(), call.dooFoo("narf"), call.doFoo("zort")] mockFoo.assert_has_calls(fooCalls, any_order = True) # AssertionError: (call.dooFoo('narf'),) not all found in call list |
在assert_has_calls()的两个例子中,注意到关键字call是出现在每个方法的前面。这个关键字是一个helper对象,标记出mock对象的方法属性。为了使用call关键字,请确保使用如下的方法从mocke模块导入helper:
from mock import Mock, call
管理Mock
Mock类的第三套方法允许你控制和管理mock对象。你可以更改mock的行为,改变它的属性或者将mock恢复到测试前的状态。你甚至可以更改每个mock方法或者mock本身的响应值。attach_mock()方法让你在mock中添加第二个mock对象。这个方法带有两个参数:第二个mock对象(aMock)和一个属性名称(aName)。
Listing Fourteen 样式了attach_mock()方法的使用。那儿,我创建了两个mock对象mockFoo和mockBar,他们有不同spec参数(第25行和第30行)。我用attach_mock()方法将mockBar添加到mockFoo中,命名为fooBar(第35行)。一旦添加成功,我就能通过property fooBar访问第二mock对象和它的属性(46~53行)。并且我仍然可以访问第一个mock对象mockFoo的属性。
Listing Fourteen
from mock import Mock # The mock object class Foo(object): # instance properties _fooValue = 123 def callFoo(self): print "Foo:callFoo_" def doFoo(self, argValue): print "Foo:doFoo:input = ", argValue class Bar(object): # instance properties _barValue = 456 def callBar(self): pass def doBar(self, argValue): pass # create the first mock object mockFoo = Mock(spec = Foo) print mockFoo # returns <Mock spec='Foo' id='507120'> # create the second mock object mockBar = Mock(spec = Bar) print mockBar # returns: <Mock spec='Bar' id='2784400'> # attach the second mock to the first mockFoo.attach_mock(mockBar, 'fooBar') # access the first mock's attributes print mockFoo # returns: <Mock spec='Foo' id='495312'> print mockFoo._fooValue # returns: <Mock name='mock._fooValue' id='428976'> print mockFoo.callFoo() # returns: <Mock name='mock.callFoo()' id='448144'> # access the second mock and its attributes print mockFoo.fooBar # returns: <Mock name='mock.fooBar' spec='Bar' id='2788592'> print mockFoo.fooBar._barValue # returns: <Mock name='mock.fooBar._barValue' id='2788016'> print mockFoo.fooBar.callBar() # returns: <Mock name='mock.fooBar.callBar()' id='2819344'> print mockFoo.fooBar.doBar("narf") # returns: <Mock name='mock.fooBar.doBar()' id='4544528'> |
configure_mock()方法让你批量的更改mock对象。它唯一的参数是一个键值对序列,每个键就是你想要修改的属性。如果你的对象没有指定的属性,configure_mock()将在mock中添加属性。
Listing fifteen显示了configure_mock()方法的运用。再次,我定义了一个spec为类Foo和return_value为555的mock对象mockFoo(第13行)。然后使用configure_mock()方法更改return_value为999(第17行)。当我直接调用mockFoo时,获得的结果为999,替换了原来的555。
Listing Fifteen
from mock import Mock class Foo(object): # instance properties _fooValue = 123 def callFoo(self): print "Foo:callFoo_" def doFoo(self, argValue): print "Foo:doFoo:input = ", argValue mockFoo = Mock(spec = Foo, return_value = 555) print mockFoo() # returns: 555 mockFoo.configure_mock(return_value = 999) print mockFoo() # returns: 999 fooSpec = {'callFoo.return_value':"narf", 'doFoo.return_value':"zort", 'doFoo.side_effect':StandardError} mockFoo.configure_mock(**fooSpec) print mockFoo.callFoo() # returns: narf print mockFoo.doFoo("narf") # raises: StandardError fooSpec = {'doFoo.side_effect':None} mockFoo.configure_mock(**fooSpec) print mockFoo.doFoo("narf") # returns: zort |
接着,我准备了一个字段对象(fooSpec),对两个mock方法设置了返回值,为doFoo()设置了side_effect(第21行)。我将fooSpec传入configure_mock(),注意fooSpec带有前缀'**'(第22行)。现在调用callFoo()结果返回“narf”。调用doFoo(),无论输入什么,引发StandardError 信号(行24~27)。如果我修改了fooSpec,设置doFoo()的side_effect的值为None,当我调用doFoo()时,将得到结果“zort”(29~32行)。
下一个方法mock_add_spec()让你向mock对象添加新的属性。除了mock_add_spec()工作在一个已存在的对象上之外,它的功能类似于构造器的spec参数。它擦除了一些构造器设置的属性。这个方法带有两个参数:spec属性(aSpec)和spc_set标志(aFlag)。再次,spce可以是字符串列表或者是类。已添加的属性缺省状态是只读的,但是通过设置spec_set标志为True,可以让属性可写。
Listing Sixteen演示了mock_add_spec()的运用。mock对象mockFoo开始的属性来自于类Foo(第25行)。当我访问两个属性(_fooValue和callFoo())时,我得到结果确认他们是存在的(29~32行)。
Listing Sixteen
from mock import Mock # The class interfaces class Foo(object): # instance properties _fooValue = 123 def callFoo(self): print "Foo:callFoo_" def doFoo(self, argValue): print "Foo:doFoo:input = ", argValue class Bar(object): # instance properties _barValue = 456 def callBar(self): pass def doBar(self, argValue): pass # create the mock object mockFoo = Mock(spec = Foo) print mockFoo # returns <Mock spec='Foo' id='507120'> print mockFoo._fooValue # returns <Mock name='mock._fooValue' id='2788112'> print mockFoo.callFoo() # returns: <Mock name='mock.callFoo()' id='2815376'> # add a new spec attributes mockFoo.mock_add_spec(Bar) print mockFoo # returns: <Mock spec='Bar' id='491088'> print mockFoo._barValue # returns: <Mock name='mock._barValue' id='2815120'> print mockFoo.callBar() # returns: <Mock name='mock.callBar()' id='4544368'> print mockFoo._fooValue # raises: AttributeError: Mock object has no attribute '_fooValue' print mockFoo.callFoo() # raises: AttributeError: Mock object has no attribute 'callFoo' |
然后,我使用mock_add_spec()方法添加类Bar到mockFoo(第35行)。mock对象现在的属性已声明在类Bar中(39~42行)。如果我访问任何Foo属性,mock对象将引发AttributeError 信号,表示他们不存在(44~47行)。
最后一个方法resetMock(),恢复mock对象到测试前的状态。它清除了mock对象的调用统计和断言。它不会清除mock对象的return_value和side_effect属性和它的方法属性。这样做是为了重新使用mock对象避免重新创建mock的开销。
最后,你能给每个方法属性分配返回值或者side-effect。你能通过return_value和side_effect访问器做到这些。例如,按如下的语句通过return_value访问器设置方法callFoo()的返回值为"narf":
mockFoo.callFoo.return_value = "narf" 按如下的语句通过side_effect访问器 设置方法callFoo()的side-ffect为TypeError mockFoo.callFoo.side_effect = TypeError 传入None清除side-effect mockFoo.callFoo.side_effect = None 你也可以用这个两个相同的访问器改变mock对象对工厂调用的响应值 |
Mock统计
最后一套方法包含跟踪mock对象所做的任意调用的访问器。当mock对象获得工厂调用时,访问器called返回True,否则返回False。查看Listing Seventeen中的代码,我创建了mockFoo之后,called访问器返回了结果False(19~20行)。如果我做了一个工厂调用,它将返回结果True(22~23行)。但是如果我创建了第二个mock对象,然后调用了mock方法callFoo()(第30行)?在这个例子中,called访问器仅仅放回了False结果(31~32行)。
Listing Seventeen
from mock import Mock # The mock object class Foo(object): # instance properties _fooValue = 123 def callFoo(self): print "Foo:callFoo_" def doFoo(self, argValue): print "Foo:doFoo:input = ", argValue # create the first mock object mockFoo = Mock(spec = Foo) print mockFoo # returns <Mock spec='Foo' id='507120'> print mockFoo.called # returns: False mockFoo() print mockFoo.called # returns: True mockFoo = Mock(spec = Foo) print mockFoo.called # returns: False mockFoo.callFoo() print mockFoo.called # returns: False |
访问器call_count给出了mock对象被工厂调用的次数。查看Listing Eighteen中的代码。我创建mockFoo之后,call_count给出的期望结果为0(19~20行)。当我对mockFoo做了一个工厂调用时,call_count增加1(22~24行)。当我调用mock方法callFoo()时,call_count没有改变(26~28行)。如果我做了第二次工厂调用call_count将再增加1。
Listing Eighteen
from mock import Mock # The mock object class Foo(object): # instance properties _fooValue = 123 def callFoo(self): print "Foo:callFoo_" def doFoo(self, argValue): print "Foo:doFoo:input = ", argValue # create the first mock object mockFoo = Mock(spec = Foo) print mockFoo # returns <Mock spec='Foo' id='507120'> print mockFoo.call_count # returns: 0 mockFoo() print mockFoo.call_count # returns: 1 mockFoo.callFoo() print mockFoo.call_count # returns: 1 |
访问器call_args返回工厂调用已用的参数。Listing Nineteen演示了它的运用。对于新创建的mock对象(mockFoo),call_args访问器返回结果为None(17~21行)。如果我做了一个工厂调用,在输入中传入"zort",call_args报告的结果为call('zort')(23~25行)。注意结果中的call关键字。对于第二个没有输入的工厂调用,call_args返回call()(27~29行)。第三个工厂调用,输入“troz”,call_args给出结果为call('troz')(31~33行)。但是当我调用mock方法callFoo()时,call_args访问器仍然返回call('troz')(35~37行)。
Listing Nineteen
#!/usr/bin/python from mock import Mock # The mock object class Foo(object): # instance properties _fooValue = 123 def callFoo(self): print "Foo:callFoo_" def doFoo(self, argValue): print "Foo:doFoo:input = ", argValue # create the first mock object mockFoo = Mock(spec = Foo, return_value = "narf") print mockFoo # returns <Mock spec='Foo' id='507120'> print mockFoo.call_args # returns: None mockFoo("zort") print mockFoo.call_args # returns: call('zort') mockFoo() print mockFoo.call_args # returns: call() mockFoo("troz") print mockFoo.call_args # returns: call('troz') mockFoo.callFoo() print mockFoo.call_args # returns: call('troz') |
访问器call_args_list 也报告了工厂调用中已使用的参数。但是call_args返回最近使用的参数,而call_args_list返回一个列表,第一项为最早的参数。Listing Twenty显示了这个访问的的运用,使用了和Listing Nineteen相同的代码。
Listing Twenty
from mock import Mock # The mock object class Foo(object): # instance properties _fooValue = 123 def callFoo(self): print "Foo:callFoo_" def doFoo(self, argValue): print "Foo:doFoo:input = ", argValue # create the first mock object mockFoo = Mock(spec = Foo, return_value = "narf") print mockFoo # returns <Mock spec='Foo' id='507120'> mockFoo("zort") print mockFoo.call_args_list # returns: [call('zort')] mockFoo() print mockFoo.call_args_list # returns: [call('zort'), call()] mockFoo("troz") print mockFoo.call_args_list # returns: [call('zort'), call(), call('troz')] mockFoo.callFoo() print mockFoo.call_args_list # returns: [call('zort'), call(), call('troz')] |
访问器mothod_calls报告了测试对象所做的mock方法的调用。它的结果是一个列表对象,每一项显示了方法的名称和它的参数。
Listing Twenty-one演示了method_calls的运用。对新创建的mockFoo,method_calls返回了空列表(15~19行)。当做了工厂调用时,同样返回空列表(21~23行)。当我调用了mock方法callFoo()时,method_calls返回一个带一项数据的列表对象(25~27行)。当我调用doFoo(),并传入"narf"参数时,method_calls返回带有两项数据的列表(29~31行)。注意每个方法名称是按照它调用的顺序显示的。
Listing Twenty-one
from mock import Mock # The mock object class Foo(object): # instance properties _fooValue = 123 def callFoo(self): print "Foo:callFoo_" def doFoo(self, argValue): print "Foo:doFoo:input = ", argValue # create the first mock object mockFoo = Mock(spec = Foo, return_value = "poink") print mockFoo # returns <Mock spec='Foo' id='507120'> print mockFoo.method_calls # returns [] mockFoo() print mockFoo.method_calls # returns [] mockFoo.callFoo() print mockFoo.method_calls # returns: [call.callFoo()] mockFoo.doFoo("narf") print mockFoo.method_calls # returns: [call.callFoo(), call.doFoo('narf')] mockFoo() print mockFoo.method_calls # returns: [call.callFoo(), call.doFoo('narf')] |
最后一个访问器mock_calls报告了测试对象对mock对象所有的调用。结果是一个列表,但是工厂调用和方法调用都显示了。Listing Twenty-two演示这个访问器的运用,使用了和Listing Twenty-one相同的代码
Listing Twenty-two
from mock import Mock # The mock object class Foo(object): # instance properties _fooValue = 123 def callFoo(self): print "Foo:callFoo_" def doFoo(self, argValue): print "Foo:doFoo:input = ", argValue # create the first mock object mockFoo = Mock(spec = Foo, return_value = "poink") print mockFoo # returns <Mock spec='Foo' id='507120'> print mockFoo.mock_calls # returns [] mockFoo() print mockFoo.mock_calls # returns [call()] mockFoo.callFoo()> print mockFoo.mock_calls # returns: [call(), call.callFoo()] mockFoo.doFoo("narf") print mockFoo.mock_calls # returns: [call(), call.callFoo(), call.doFoo('narf')] mockFoo() print mockFoo.mock_calls # returns: [call(), call.callFoo(), call.doFoo('narf'), call()] |
在测试中使用MOCK
数据类型,模型或者节点,这些是mock对象可能被假定的一些角色。但是mock对象怎样适合单元测试呢?让我们一起来看看,来自Martin Fowler的文章Mocks Aren't Stubs采取了简化的设置。
在这个测试中,设置了三个类(图4)。Order类是测试对象。它模拟了单一项目的采购订单,订单来源于一个数据源。Warehouse类是测试资源。它包含了键值对的序列,键是项目的名称,值是可用的数量。OrderTest类是测试用例本身。
图4
Listing Twenty-three描述了Order。Order类声明了三个属性:项目名称(_orderItem),要求的数量(_orderAmount)和已填写的数量(_orderFilled)。它的构造器带有两个参数(8~18行),填入的属性是_orderItem和_orderAmount。它的__repr__()方法返回了购买清单的摘要(21~24行)。
Listing Twenty-three
class Order(object): # instance properties _orderItem = "None" _orderAmount = 0 _orderFilled = -1 # Constructor def __init__(self, argItem, argAmount): print "Order:__init__" # set the order item if (isinstance(argItem, str)): if (len(argItem) > 0): self._orderItem = argItem # set the order amount if (argAmount > 0): self._orderAmount = argAmount # Magic methods def __repr__(self): # assemble the dictionary locOrder = {'item':self._orderItem, 'amount':self._orderAmount} return repr(locOrder) # Instance methods # attempt to fill the order def fill(self, argSrc): print "Order:fill_" try: # does the warehouse has the item in stock? if (argSrc is not None): if (argSrc.hasInventory(self._orderItem)): # get the item locCount = argSrc.getInventory(self._orderItem, self._orderAmount) # update the following property self._orderFilled = locCount else: print "Inventory item not available" else: print "Warehouse not available" except TypeError: print "Invalid warehouse" # check if the order has been filled def isFilled(self): print "Order:isFilled_" return (self._orderAmount == self._orderFilled) |
Order类定义了两个实例方法。fill()方法从参数(argSrc)中获取数据源。它检查数据源是否可用,数据源的项目是否存在问题(33~34行)。它提交了一个申请并用实际返回的数量更新_orderFilled(36~39行)。当_orderAmount和_orderFilled有相同的值时,isFilled()方法返回True(48~50行)。
Listing Twenty-four描述了Warehouse类。它是一个抽象类,声明了属性和方法接口,但是没有定义方法本身。属性_houseName是仓库的名字,而_houseList是它持有的库存。还有这两个属性的访问器。
Listing Twenty-four
class Warehouse(object): # private properties _houseName = None _houseList = None # accessors def warehouseName(self): return (self._houseName) def inventory(self): return (self._houseList) # -- INVENTORY ACTIONS # set up the warehouse def setup(self, argName, argList): 	pass # check for an inventory item def hasInventory(self, argItem): pass # retrieve an inventory item def getInventory(self, argItem, argCount): pass # add an inventory item def addInventory(self, argItem, argCount): pass |
Warehouse类声明了四个方法接口。方法setup()带有两个参数,是为了更新这两个属性。方法hasInventory()参数是项目的名称,如果项目在库存中则返回True。方法getInventory()的参数是项目的名称和数量。它尝试着从库存中扣除数量,返回哪些是成功的扣除。方法addInventory()的参数也是项目名称和数量。它将用这两个参数更新_houseList。
Listing Twenty-five是测试用例本身,orderTest类。他有一个属性fooSource是Order类所需的mock对象。setUp()方法识别执行的测试例程(14~16行),然后创建和配置mock对象(21~34行)。tearDown()方法向stdout打印一个空行。
Listing Twenty-five
import unittest from mock import Mock, call class OrderTest(unittest.TestCase): # declare the test resource fooSource = None # preparing to test def setUp(self): """ Setting up for the test """ print "OrderTest:setUp_:begin" # identify the test routine testName = self.id().split(".") testName = testName[2] print testName # prepare and configure the test resource if (testName == "testA_newOrder"): print "OrderTest:setup_:testA_newOrder:RESERVED" elif (testName == "testB_nilInventory"): self.fooSource = Mock(spec = Warehouse, return_value = None) elif (testName == "testC_orderCheck"): self.fooSource = Mock(spec = Warehouse) self.fooSource.hasInventory.return_value = True self.fooSource.getInventory.return_value = 0 elif (testName == "testD_orderFilled"): self.fooSource = Mock(spec = Warehouse) self.fooSource.hasInventory.return_value = True self.fooSource.getInventory.return_value = 10 elif (testName == "testE_orderIncomplete"): self.fooSource = Mock(spec = Warehouse) self.fooSource.hasInventory.return_value = True self.fooSource.getInventory.return_value = 5 else: print "UNSUPPORTED TEST ROUTINE" # ending the test def tearDown(self): """Cleaning up after the test""" print "OrderTest:tearDown_:begin" print "" # test: new order # objective: creating an order def testA_newOrder(self): # creating a new order testOrder = Order("mushrooms", 10) print repr(testOrder) # test for a nil object self.assertIsNotNone(testOrder, "Order object is a nil.") # test for a valid item name testName = testOrder._orderItem self.assertEqual(testName, "mushrooms", "Invalid item name") # test for a valid item amount testAmount = testOrder._orderAmount self.assertGreater(testAmount, 0, "Invalid item amount") # test: nil inventory # objective: how the order object handles a nil inventory def testB_nilInventory(self): """Test routine B""" # creating a new order testOrder = Order("mushrooms", 10) print repr(testOrder) # fill the order testSource = self.fooSource() testOrder.fill(testSource) # print the mocked calls print self.fooSource.mock_calls # check the call history testCalls = [call()] self.fooSource.assert_has_calls(testCalls) # ... continued in the next listing |
OrderTest类有五个测试例程。所有五个测试例程在开始的时候都创建了一个Order类的实例。例程testA_newOrder()测试Order对象是否可用是否有正确的数据(46~60行)。例程testB_nilWarehouse()创建了一个空的mock并传入Order对象的fill()方法(64~79行)。它检查了mock的调用历史,确保仅仅发生了工厂调用。
例程testC_orderCheck()(Listing Twenty-six)测试了Order对象在库存不足时的反应。最初,fooSource的hasInventory()方法响应True,getinventory()方法返回0。测试例程检查是否订单未达成,是否正确的mock方法被带调用(16~19行)。然后测试例程创建了一个新的Order对象,这次是一个不同的项目。mock(fooSource)的方法hasInventory()的响应设置为False(第27行)。再次,例程检查是否订单未达成,是否调用了正确的mock方法(34~37行)。注意使用reset_mock()方法将fooSource恢复到测试前的状态(第28行)
Listing Twenty-six
class OrderTest(unittest.TestCase): # ... see previous listing # test: checking the inventory # objective: does the order object check for inventory? def testC_orderCheck(self): """Test routine C""" # creating a test order testOrder = Order("mushrooms", 10) print repr(testOrder) # perform the test testOrder.fill(self.fooSource) # perform the checks self.assertFalse(testOrder.isFilled()) self.assertEqual(testOrder._orderFilled, 0) self.fooSource.hasInventory.assert_called_once_with("mushrooms") print self.fooSource.mock_calls # creating another order testOrder = Order("cabbage", 10) print repr(testOrder) # reconfigure the test resource self.fooSource.hasInventory.return_value = False self.fooSource.reset_mock() # perform the test testOrder.fill(self.fooSource) # perform the checks self.assertFalse(testOrder.isFilled()) self.assertEqual(testOrder._orderFilled, -1) self.fooSource.hasInventory.assert_called_once_with("cabbage") print self.fooSource.mock_calls # ... continued in the next listing |
测试例程testD_orderFilled()(Listing Twenty-seven)模拟了一个成功的订单事务。fooSource的hasInventory()方法响应True,getinventory()方法返回10。例程调用fill()方法传入mock对象,然后检查订单是否已完成(17~18行)。它也检查了是否采用正确的顺序和正确的参数调用了 正确的mock方法(20~24行)。
Listing Twenty-seven
# ... see previous listing # test: fulfilling an order # objective: how does the order object behave with a successful transaction def testD_orderFilled(self): """Test routine D""" # creating a test order testOrder = Order("mushrooms", 10) print repr(testOrder) # perform the test testOrder.fill(self.fooSource) print testOrder.isFilled() |