Instead of calling the actual method, you want to mock the return value. How to mock properties in Python using PropertyMock. It doesn’t happen all that often, but sometimes when writing unit tests you want to mock a property and specify a return value. Returning a few different values from Mock, raising different exceptions . The mock library provides a PropertyMock for that, but using it probably doesn’t work the way you would initially think it would.. os_stat.return_value by default, returns a new Mock object instance that will be substituted for the constructor method's return value (the stat object instance) - in the scope of def test, which includes the nested function call to original_func. I want to mock out this class using the Python Mock library. How do I attach the return value of mock.patch(…).start() to a parent mock? How to return a value from a method by delay? How to Mock a javax.servlet.ServletInputStream; To Verify a mock, is a return required to verify; How to return a particular value from a method? Add to this the fact that practically every class in the computer world has either a title or a name attribute and you have got yourself a … How to return a Enum value from a string? But then there is name , which nobody ever remembers. unittest.mock provides a class called Mock which you will use to imitate real objects in your codebase.Mock offers incredible flexibility and insightful data. Instead of calling the actual method, you want to mock the return value. The @mock.patch("os.stat") decorator is mocking os.stat(), the constructor method of the stat class. My favorite documentation is objective-based: I’m trying to achieve X objective, here are some examples of how library Y can help. patch will forward keyword arguments to the Mock class, so to configure a return_value we simply add it as one: Mocking classes It’s quite common to patch classes completely or partially. This, along with its subclasses, will meet most Python mocking needs that you will face in your tests. The following are 30 code examples for showing how to use unittest.mock.return_value().These examples are extracted from open source projects. The library also provides a function, called patch(), which replaces the real objects in your code with Mock instances. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. The rule is simple – if a value passed as side_effect is an Exception class or instance, it will get raised. However, it turns out side_effect has more interesting applications…. Here are the examples of the python api mock.return_value taken from open source projects. class Foo: def method_1(): results = uses_some_other_method() def method_n(): results = uses_some_other_method() Suppose the above code is in foo.py and uses_some_other_method is defined in … Questions: I have a class that I’m testing which has as a dependency another class (an instance of which gets passed to the CUT’s init method). By voting up you can indicate which examples are most useful and appropriate. The Mock class has a few input arguments, most of them (like return_value ) are easy to remember. class Foo: def method_1(): results = uses_some_other_method() def method_n(): results = uses_some_other_method() Okay, suppose the above code is in foo.py, uses_some_other_method … Exception class or instance, it will get raised which examples are extracted open... 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