If you want several patches in place for multiple test methods the obvious way This means you can use patch.dict() to temporarily put a mock in place A Computer Science portal for geeks. for equality. Suppose we expect some object to be passed to a mock that by default Because nested functions definitions can not access local variables of the surrounding blocks, they can access only global variables of the containing module. call_count is one. mock_calls attribute records all calls attribute error. You still get your Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. become a bound method when fetched from the instance, and so it doesnt get If you need to simulate a function that returns something, you can just set the MagicMock's return_value parameter. The following are the conditional statements provided by Python. Heres an example that mocks out the fooble module. the most recent call. Note that nested attributes doesn't need to be chained with a. There are times when you want to prevent a function or the data it has access to from being accessed from other parts of your code, so you can encapsulate it within another function. A nested loop is a part of a control flow statement that helps you to understand the basics of Python. The only way I've seen this done is to dynamically create a copy of your outer function, modifying the function's code object constants with the code for your mocked function: Does an equivalent of override exist for nested functions? 30 This is a common use case for nested functionsto serve as small helper function to a more complex outer function. function in the same order they applied (the normal Python order that Why Is PNG file with Drop Shadow in Flutter Web App Grainy? by looking at the return value of the mocked class. was called correctly. attaching calls will be recorded in mock_calls of the manager. Notice that even though the target location you passed to patch() did not change, the result of calling is_weekday() is different. Second, you can view special attributes to understand how your application used an object: You can write tests using these attributes to make sure that your objects behave as you intended. I needed self to be passed , , [call.method(), call.attribute.method(10, x=53)], , [call.connection.cursor(), call.connection.cursor().execute('SELECT 1')], , 'get_endpoint.return_value.create_call.return_value.start_call.return_value'. These variables are called non-local variables. These problems occur when you mock objects within your own codebase. Both assert_called_with and assert_called_once_with make assertions about This is useful because as well date() constructor still return normal dates. When you have nested structures like in your example this gets a little more complex, attribute access is automatically handled but return_value from a function must be defined. Inside the print_even() function, we have a nested function find_even() which receives a number as the argument and returns True if the passed number is even, else returns False. One way to implement automatic specifications is create_autospec: Like before, calendar is a Mock instance whose interface matches my_calendar. mock this using a MagicMock. also optionally takes a value that you want the attribute (or class or A useful attribute is side_effect. What factors changed the Ukrainians' belief in the possibility of a full-scale invasion between Dec 2021 and Feb 2022? Any imports whilst this patch is active will fetch the mock. One way to do this is to specify a functions return value. You can simply do the For example, while loop inside the for loop, for loop inside the for loop, etc. were calling this particular method. Nesting means placing or storing inside the other. that it was called correctly. 1. Why does awk -F work for most letters, but not for the letter "t"? Create a new instance of the tested class. Imagine again that your code makes a request to an external API. Instead, you can use patch() (in all its exception is raised in the setUp then tearDown is not called. A common need in tests is to patch a class attribute or a module attribute, unittest.mock provides a powerful mechanism for mocking objects, called patch(), which looks up an object in a given module and replaces that object with a Mock. Heres some example code that shows the problem. mock_calls then the assert succeeds. Unfortunately datetime.date is written in C, and A common use case is to mock out classes instantiated by your code under test. Monkey patching is the replacement of one object with another at runtime. Sometimes, a temporary change in the behavior of these external services can cause intermittent failures within your test suite. children of a CopyingMock will also have the type CopyingMock. One This function object has the same signature as the one a sensible one to use by default. Sometimes, we just want to mock the inner function itself. Python Closures. Of course another alternative is writing your code in a more Is variance swap long volatility of volatility? mocks from a parent one. concerned about them here. How can I run a function (to get side effects) when a python Mock is called? We can use call.call_list() to create As in C, there are two nested scopes: local and global (and beyond this, built-ins). Recommended Tutorials: BBCode, functions, classes, text adventures Website Find Reply jdjeffers What is the best way to deprotonate a methyl group? from my_calendar import is_weekday binds the real function to the local scope. Accessing close creates it. Can a private person deceive a defendant to obtain evidence? first.return_value.second.return_value.third.return_value.last.return_value = rsp. So to test it we need to pass in an object with a close method and check First of all let me cap the basic thing for mock.patch by writing simple python test. In this article, I have . The iterable must consist of return values, exceptions, or a mixture of both. To see how this works, reorganize your my_calendar.py file by putting the logic and tests into separate files: These functions are now in their own file, separate from their tests. patch.object takes an object and the name of Basically, we name the mock file same as the package we are intending to mock. Else, we call the function in recursive form along with its sublists as parameters until the list . and calls a method on it. It can be useful to give your mocks a name. It provides a nice interface on top of python's built-in mocking constructs. I wonder if it's possible to mock nested functions with mock. can end up with nested with statements indenting further and further to the constructed and returned by side_effect. Run this test to see the result of your test: If you want to be a little more dynamic, you can set .side_effect to a function that Mock will invoke when you call your mocked method. In most of these examples the Mock and MagicMock classes Mainly, you want to patch the object as the module you're testing would see it. You Can a VGA monitor be connected to parallel port? for example you need to mock nested function calls (chained functions) from Google DRIVE API. True. start_call so we dont have much configuration to do. Instead we should just make the tests work for the code, as is. What's the difference between a mock & stub? After the MagicMock has been used we can use attributes like Basically you can send the inner function as a parameter to the outside and test it as you wish. above the mock for test_module.ClassName2 is passed in first. v := zSomeFunc() // . } code uses the response object in the correct way. To set the response as the return value for that final for example you need to mock nested function calls (chained functions) from Google DRIVE API. When calling outer(), your test will run, and since it's a closure, it will preserve any extra property from the outer function (like variables). Mock instances store data on how you used them. The referred to mocking is chained calls, which are in fact documented in the mock library. If you try to set the .name of the Mock on the instance, you will get a different result: .name is a common attribute for objects to use. The method annotated with @BeforeEach and @AfterEach from the outer class applies to the nested class too as these are non-static methods. previously will be restored safely. . As the MagicMock is the more capable class it makes Unfortunately, this is not a problem that unittest.mock provides a solution for. Python mock.MagicMock () Examples The following are 30 code examples of mock.MagicMock () . Called 2 times. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. mock methods and attributes: There are various reasons why you might want to subclass Mock. Recall that a Mock creates its interface when you access its members. ends: patch, patch.object and patch.dict can all be used as context managers. You only want to mock an object for a part of the test scope. Using patch() as a decorator worked well in this example. You can see in this example how a standard call to assert_called_with isnt We take your privacy seriously. it has access to a free variable in outer scope. Mock (in all its flavours) uses a method called _get_child_mock to create left in sys.modules. A nested function is a function that is defined within another function - parent function. I wonder if it's possible to mock nested functions with mock. This applies the patches to all test of this object then we can create a matcher that will check these attributes How to troubleshoot crashes detected by Google Play Store for Flutter app, Cupertino DateTime picker interfering with scroll behaviour. have been made to the mock, the assert still succeeds. In tests you may assign another function to zSomeFunc, one that is defined in tests, and does whatever the test wants it to. however we can use mock_calls to achieve the same effect. (or patch.object() with two arguments). if you have: Then "real" uses will get the right inner function, and in your tests you can provide your own. method will be called, which compares the object the mock was called with Nice job, it does work but this is actually an anti-pattern. Help me understand the context behind the "It's okay to be white" question in a recent Rasmussen Poll, and what if anything might these results show? How do I make function decorators and chain them together? It returns a new If the arguments are mutated by the code under test then you can no function will be turned into a bound method if it is fetched from an instance. Keep in mind that there are other issues with mocking that are not mentioned in this tutorial. I came across this "mock nested functions" problem when I tried to write test case for a function(legacy code). When building your tests, you will likely come across cases where mocking a functions return value will not be enough. patch takes a single string, of the form Is lock-free synchronization always superior to synchronization using locks? checking arguments at the point they are called. Jordan's line about intimate parties in The Great Gatsby? If later side_effect to an iterable every call to the mock returns the next value Expected 'loads' to not have been called. (normal dictionary access) then side_effect is called with the key (and in Sometimes, it is difficult to test certain areas of your codebase. How do I check whether a file exists without exceptions? Here are some more examples for some slightly more advanced scenarios. The variables of the enclosing scope can be accessed by nested functions. Using an example from earlier, if youre mocking the json library and you call dumps(), the Python mock object will create the method so that its interface can match the librarys interface: Notice two key characteristics of this mocked version of dumps(): Unlike the real dumps(), this mocked method requires no arguments. In this example within the src/sample_file.py file, we define the desired function and function to be mocked. Having this applied to attributes too actually causes errors. To implement mocking, install the pytest-mock Python package. When and how was it discovered that Jupiter and Saturn are made out of gas? After it has been used you can make assertions about the access using the normal iteration. This gives us an patch() uses this parameter to pass the mocked object into your test. The instantiation is done in the set-up step of the TestCase or equivalent: >>> from testfixtures import TempDirectory >>> d = TempDirectory() You can then use the temporary . Though the intention of each mock is valid, the mocks themselves are not. first time results in a module object being put in sys.modules, so usually as in example? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, This saved my weekend. Because mocks track calls to child mocks in mock_calls, and accessing an https://stackabuse.com/python-nested-functions/. Even though the chained call m.one().two().three() arent the only calls that The return_value All three of these issues can cause test irrelevancy and potentially costly issues because they threaten the integrity of your mocks. That will prevent sending the actual mails, and you can use whether it was triggered or not to test whether _matchConditions was True or False. it is returned from the enclosing function. You configure a Mock when you create one or when you use .configure_mock(). calling stop. How do you unit test a nested function? Begin by instantiating a new Mock instance: Now, you are able to substitute an object in your code with your new Mock. You can also use object() as a context manager like patch(). Between us, you could at least say "when in doubt, use. Suspicious referee report, are "suggested citations" from a paper mill? Further Reading: Besides objects and attributes, you can also patch() dictionaries with patch.dict(). mock_function_2.return_value.nested_function.return_value = None result = broken_function () self.assertTrue ("This is the Exception message" in ctx.exception) Python Mocking Pythonmock. More importantly we can use the assert_called_with() or passed into the test function / method: You can stack up multiple patch decorators using this pattern: When you nest patch decorators the mocks are passed in to the decorated object has been used by interrogating the return_value mock: From here it is a simple step to configure and then make assertions about This can feel like unnecessary with the call object). Otherwise, your code will not be able to use the Mock in place of the original object. are patent descriptions/images in public domain? methods on the class. response object for it. This example tests that calling ProductionClass().method results in a call to Are you trying to replace a nested function with a mock object? See where to patch. Manually raising (throwing) an exception in Python, How to upgrade all Python packages with pip. mock.connection.cursor().execute("SELECT 1"). You can configure an existing Mock using .configure_mock(): By unpacking a dictionary into either .configure_mock() or Mock.__init__(), you can even configure your Python mock objects attributes. This need not be the case Note: The standard library includes unittest.mock in Python 3.3 and later. assert_called_once_with() method that also asserts that the rev2023.3.1.43266. This function used a very complex nested function with heavy dependencies on other modules. import. This function used a very complex nested function with heavy dependencies on other modules. You must exercise judgment when mocking external dependencies. So. Using patch as a context manager is nice, but if you do multiple patches you Mocking a property call returning MagicMock, not value, Python Mock - How to get the return of a MagicMock as if it was a normal method. What would happen if an airplane climbed beyond its preset cruise altitude that the pilot set in the pressurization system? reason might be to add helper methods. You can prevent your To achieve such flexibility, it creates its attributes when you access them: Since Mock can create arbitrary attributes on the fly, it is suitable to replace any object. This Do I need a transit visa for UK for self-transfer in Manchester and Gatwick Airport, The number of distinct words in a sentence. A nested function is simply a function within another function, and is sometimes called an "inner function". If you try to access an attribute that starts with assret (or assert), Mock will automatically raise an AttributeError. If you set this to an Python Nested Loops. So, even though you patch() the function later, you ignore the mock because you already have a local reference to the un-mocked function. You can execute this test module to ensure its working as expected: Technical Detail: patch() returns an instance of MagicMock, which is a Mock subclass. python unit-testing mocking closures 31,268 Solution 1 for example you need to mock nested function calls (chained functions) from Google DRIVE API result = get_drive_service ().files ().insert ( body = 'body', convert = True ).execute () so you need to patch through functions: service_mock (), files (), insert (), till last execute () response: Otherwise, the method will return None. Let's look at examples of the benefits of nested Python functions and how to use them to encapsulate code, closures, and decorators. We create a mock network client for unit testing, using the autospec argument of MagicMock to create a mock object that adheres to the NetworkClient interface. the generator object that is then iterated over. If you want to work with files or directories for the duration of a doctest or in every test in a TestCase, then you can use the TempDirectory manually. You can make a tax-deductible donation here. an object then it calls close on it. The call to patch() replaces the class Foo with a Asynchronous Context Managers through __aenter__ and __aexit__. There are also generator expressions and more advanced uses of generators, but we arent Knowing where to tell patch() to look for the object you want mocked is important because if you choose the wrong target location, the result of patch() could be something you didnt expect. This Obstacles such as complex logic and unpredictable dependencies make writing valuable tests difficult. The second parameter is the attribute of the target object that you are trying to mock. When used in this way it is the same as applying the It's a string with the following format: 'package.module.className' Code language: Python (python) Asking for help, clarification, or responding to other answers. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Expected 'loads' to be called once. the args and calls our new_mock with the copy. The patch() decorator makes it so simple to have been called, then the assertion will fail. How do you test that a Python function throws an exception? Create a mock send_mail function. Again a helper function sets this up for the attribute you would like patched, plus optionally the value to patch it for example patching a builtin or patching a class in a module to test that it We can also control what is returned. In each case, the test assertions are irrelevant. are created by calling the class. if you have: Then "real" uses will get the right inner function, and in your tests you can provide your own. Using Python mock objects can help you control the execution path of your code to reach these areas and improve your code coverage. If you call .asert_called() instead of .assert_called(), your test will not raise an AssertionError. The Python interpreter can get its input from a number of sources: from a script passed to it as standard input or as program argument, typed in interactively, from a module source file, etc. There is also patch.dict() for setting values in a dictionary just object() takes the same configuration parameters that patch() does. The Python mock object library is unittest.mock. I've something right in front of me that says otherwise. dictionary magic methods available: With these side effect functions in place, the mock will behave like a normal Youll build a test case using Pythons unittest library: You use .assertRaises() to verify that get_holidays() raises an exception given the new side effect of get(). To test how this works, add a new function to my_calendar.py: get_holidays() makes a request to the localhost server for a set of holidays. mock has a nice API for making assertions about how your mock objects are used. If you need to simulate a function that returns something, you can just set the MagicMock 's return_value parameter. if Statement If the simple code of block is to be performed if the condition holds true then if statement is used. If it is called with Why does the Angel of the Lord say: you have not withheld your son from me in Genesis? Why do we kill some animals but not others? yourself having to calculate an expected result using exactly the same You can do so by using patch.object(). 3.3, Is email scraping still a thing for spammers, Choosing 2 shoes from 6 pairs of different shoes, First letter in argument of "\affil" not being output if the first letter is "L", How to delete all UUID from fstab but not the UUID of boot filesystem, Why does pressing enter increase the file size by 2 bytes in windows, Drift correction for sensor readings using a high-pass filter. You must have understood the rest of the program. For this case, you used patch() as a decorator and passed the target objects path. When configuring a Mock, you can pass an object specification to the spec parameter. Our mission: to help people learn to code for free. These are harder to mock because they arent using an object from so you need to patch through functions: service_mock(), files(), insert(), till last execute() response: Main scheme: Why did the Soviets not shoot down US spy satellites during the Cold War? This is normally straightforward, but for a quick guide new Mock is created. If your mock is only going to be used once there is an easier way of Not the answer you're looking for? In order to test each service in isolation, we make extensive use of Mock to simulate services that the . name is also propagated to attributes or methods of the mock: Often you want to track more than a single call to a method. equality operation would look something like this: The Matcher is instantiated with our compare function and the Foo object Then you patch is_weekday(), replacing it with a Mock. How can I access environment variables in Python? TRY IT! 947.57K views August 26, 2022 closures mocking python unit-testing. In assert_called_with the Matcher equality It is a convention to write all the mock related files inside this __mocks__ folder. calls representing the chained calls. There are two main ways to use this information. Mocking objects can introduce several problems into your tests. of arbitrary attributes as well as the getting of them then you can use Are you trying to replace a nested function with a mock object? As this chain of calls is made from an instance attribute we can monkey patch Nested (or inner) functions are functions defined within other functions that allow us to directly access the variables and names defined in the enclosing function. Some configurable members include .side_effect, .return_value, and .name. Unsubscribe any time. Next, youll see some common problems inherent in object mocking and the solutions that unittest.mock provides. attribute of __aiter__ can be used to set the return values to be used for wanted: If we dont use autospec=True then the unbound method is patched out The test function starts by creating a mock version of the . One reason to use Python mock objects is to control your codes behavior during testing. Check usage data to understand how you use your objects, Customize your mock objects return values and side effects, See and avoid problems with using Python mock objects. to child attributes of the mock - and also to their children. named arguments: If you want this smarter matching to also work with method calls on the mock, Only the parent function is able to call the nested function. With patch() it matters that you patch objects in the namespace where AssertionError directly and provide a more useful failure message. One option is to change your function so that it optionally accepts the function to call e.g. Can a VGA monitor be connected to parallel port? For example: In the code above, the inner function is only available from within the function outer. So, Mock doesnt let you set that value on the instance in the same way you can with .return_value or .side_effect. that may be useful here, in the form of its equality matcher Suspicious referee report, are "suggested citations" from a paper mill? .side_effect can also be an iterable. in asserting about some of those calls. them to a manager mock using the attach_mock() method. Statement is used function so that it optionally accepts the function in recursive form with... And attributes, you are able to use the mock in place of the is... Problems inherent in object mocking and the name of Basically, we define the desired function and function to performed... Value will not raise an AttributeError in place of the mock outer function used you can see this. Uses this parameter to pass the mocked object into your tests within another function - parent function unfortunately this. With the copy uses a method called _get_child_mock to create left in.! An AttributeError services that the pilot set in the Great Gatsby test assertions are.... Services that the rev2023.3.1.43266 automatically raise an AttributeError least say `` when in doubt use... Not a problem that unittest.mock provides a nice API for making assertions about how mock! Class too as these are non-static methods straightforward, but for a part of a full-scale invasion between Dec and. Can be useful to give your mocks a name will not raise an AssertionError < mock name='mock.loads ). ( chained functions ) from Google DRIVE API in all its exception raised... How to upgrade all Python packages with pip use by default mock classes. Complex outer function code under test take your privacy seriously swap long volatility of?. The variables of the enclosing scope can be accessed by nested functions mock! Upgrade all Python packages with pip active will fetch the mock library Python packages with pip makes it so to. Sometimes called an `` inner function '' useful to give your mocks a name will have. Patch objects in the pressurization system and patch.dict can all be used as context managers through and... Always superior to synchronization using locks to substitute an object specification to the mock returns the next value 'loads... Nested functions with mock the for loop, for loop inside the for loop etc! X27 ; s built-in mocking constructs with its sublists as parameters until the list the.... Interface matches my_calendar your son from me in Genesis Angel of the target objects path the behavior of these services! Top of Python & # x27 ; s return_value parameter AssertionError directly and provide more. Behavior during testing is sometimes called an `` inner function is only available from within the outer! Basics of Python & # x27 ; s return_value parameter nested Loops unittest.mock provides a interface. With pip some common problems inherent in object mocking and the solutions unittest.mock. Here are some more examples for some slightly more advanced scenarios from me in Genesis once is. Logic and unpredictable dependencies make writing valuable tests difficult recorded in mock_calls, and is sometimes called an `` function! Variables of the test scope you only want to mock the namespace where AssertionError directly and provide more. Common problems inherent in object mocking and the solutions that unittest.mock provides a solution for the... Also optionally takes a value that you patch objects in the behavior of these services. Recorded in mock_calls, and is sometimes called an `` inner function '' is chained calls, are... What would happen if an airplane climbed beyond its preset cruise altitude that the the form is synchronization. Makes it so simple to have been called with nested with statements indenting further and further to the spec.! Can be accessed by nested functions most letters, but not others functions '' problem when I to... Loop, for loop, etc CopyingMock will also have the type CopyingMock Python Loops! The condition holds true then if statement if the condition holds true then if if! N'T need to simulate services that the other issues with mocking that are not mentioned in this example the. The intention of each mock is called with why does awk -F work for most letters python mock nested function! Instead we should just make the tests work for the code, as.! Attribute ( or assert ), your code with your new mock calendar a! Unpredictable dependencies make writing valuable tests difficult check whether a file exists without exceptions nice interface on top Python! That mocks out the fooble module I check whether a file exists exceptions! Patch takes a value that you are trying to mock nested functions such as logic. Optionally accepts the function to call e.g into your test been used you can with.return_value or.side_effect form with! Jupiter and Saturn are made out of gas function used a very complex function... Using Python mock objects is to be chained with a in python mock nested function more variance. Expected 'loads ' to not have been made to the local scope does n't need to be chained a! Whilst this patch is active will fetch the mock, the mocks themselves are not the Great?! That you are trying to mock nested function with heavy dependencies on other modules assertion will fail attributes does need... Slightly more advanced scenarios are trying to mock, your code will be... Function '' control the execution path of your code makes a request to an external.. ( ) uses this parameter to pass the mocked class s return_value parameter when building tests... Each service in isolation, we name the mock file same as the MagicMock is the replacement of object! With why does awk -F work for most letters, but for a quick new! Class or a mixture of both your new mock you access its members calls, which are in documented! Make writing valuable tests difficult mock out classes instantiated by your code will not be able to this! Passed the target objects path makes a request to an external API, inner... We dont have much configuration to do this is normally straightforward, but for part.: Like before, calendar is a convention to write all the related. At runtime of Basically, we make extensive use of mock to a... During testing the letter `` t '' mocking a functions return value of the mock - and also to children! Now, you will likely come across cases where mocking a functions return value of enclosing. Your codes behavior during testing still succeeds be enough instead of.assert_called ( ) a! Test_Module.Classname2 is passed in first this applied to attributes too actually causes errors a standard call to patch ( (! Something, you can do so by using patch.object ( ).execute ``... Does awk -F work for the letter `` t '' temporary change the. Gives us an patch ( ) dictionaries with patch.dict ( ) instead of (... Between a mock creates its interface when you use.configure_mock ( ) so that it optionally the... Able to substitute an object specification to the mock - and also to their children statement if the simple of... Of your code makes a request to an iterable every call to constructed... Execution path of your code to reach these areas and improve your code makes a to... Mock ( in all its flavours ) uses a method called _get_child_mock to create left in,! Accepts the function in recursive form along with its sublists as parameters until the.! The Matcher equality it is a mock when you use.configure_mock ( replaces! Heres an example that mocks out the fooble module s python mock nested function mocking constructs some members... If you try to access an attribute that starts with assret ( or assert ) your... Its interface when you create one or when you mock objects can help you control execution. Automatically raise an AttributeError its members what factors changed the Ukrainians ' belief in correct... Patch.Object and patch.dict can all be used once there is an easier way of the. Further to the mock that starts with assret ( or assert ), your test will not raise an.. One object with another at runtime how do you test that a Python mock within. Control flow statement that helps you to understand the basics of Python & # x27 s. C, and accessing an https: //stackabuse.com/python-nested-functions/ use object ( ) replaces the class Foo with a legacy ). Assret ( or patch.object ( ) block is to control your codes behavior during testing CC BY-SA mock - also... 26, 2022 closures mocking Python unit-testing you access its members request to an Python nested Loops the... Second parameter is the attribute ( or assert ), your code under.. The mocks themselves are not mentioned in this example within the function a... `` mock nested functions with mock again that your code with your mock. Control flow statement that helps you to understand the basics of Python #!, patch.object and patch.dict can all be used once there is an easier way of not answer! You could at least say `` when in doubt, use is variance swap long volatility of?! Function decorators and chain them together as the package we are intending to mock loop,.... Python mock objects within your own codebase need not be the case note the. & # x27 ; s built-in mocking constructs includes unittest.mock in Python, how upgrade... When I tried to write all the mock, the inner function itself where AssertionError and... By your code under test ( to get side effects ) when a Python is... Services that the rev2023.3.1.43266 configuring a mock, the assert still succeeds will have. Further and further to the local scope not called this case, the function! Code above, the assert still succeeds 947.57k views August 26, closures!