Pytest Intro

Pytest Intro Install pytest.

Task 1 Write test asserting product of two numbers is equal the fixture value.

How to run pytest in VS Code

Pytest in VS Code

Patch

Go to utils.py (implementation of Task 2b). Explore the code.

Task 2 Write test for get_ids method using patch.

Patch Patching will be used for the function utils.api_get_data_from_db to return static value.

Dependency in object oriented programming

Object that class has a direct relationship with. Class and directed object type are coupled. Class could depend on another class, because it has an attribute of that type or becauce object of that type is passed as a parameter to method, or because the class inherits. Inheritance introduce the coupling that is hard to remove. Composition is always a better choice then inheritance. Composition and Inheritance

Dependency Injection

Dependency Injection is a design pattern. The idea is that, if the class uses an object of the certain type we are not making that class responsible for that object. Because it shifts the responsibility of creating to another class dependency injection is an inversion of control technique.

Big advanatge of dependency injeciton is that your code is much easier to test.

Dependency inversion

Dependency inversion is a prinicple in SOLID design principles. Decoupled concrete classes uses abstractions, abstract classes, interfaces etc.

Because you need a class in order to construct the object. This also means that dependecy inversion is possible when you separate creation from use. Without Dependency Injection there is no Dependency Inversion.

before

Go to file before.py. Check test_authorizer.py for scucess fail.

Task 3 Create automated tests for classes in file before.py

It is hard to test PaymentProcessor for success and fail, because it creates authoriser object, calls methods and checks wheater is authorized or not.

Problem is that the pay method is responsible for creating objects which means we can NOT create it in test, sets to true and pass to the pay method.

Unit test has a mock method that allows you to mock object that are used in functions and replace that objects in those functions. IT IS HARD.

That's where DEPENDENCY INJECTION pattern comes to play.

Introduce dependency injection to ehnace testability and later dependecy inversion.

We can introduce dependency in parameter of the method or initializer in the class.

The advantage of the second is that we can use it in different places.

Remove from pay function, the generation of sms, because it is not its responsibility. Go to with_dep_inj_test.py.

Task 4 Write test for PaymentProcessor class.

Suggestion: Test how the class is created and init.

Generate the coverage report

Task 5: Check it out

https://coverage.readthedocs.io/en/7.2.7/ coverage html

coverage run test.py

coverage html

check index.html in html reader.

Dependency Inversion

Task 6: Explore the file final.py and write tests for PaymentProcessor with Authorizer_Robot.

We create a layer between that allows us to separate the payment process from authorization much clenanly.

Beacuse the payment processor only calls two methods it does not need to know we are dealing with AuthorizerSMS. We can give him an abstract class, that will have the abstract methods it needs.

Coverage issue due to abstract class

Beacuse we added this abstract class, we introduced two abstract methods which are not tested, which is true. On the other habd is useless to test those methods because they are abstract.

Coeverage ingores the method to test if we replace pass with doctring.

Dependency Inversion

Is important, allows to separate Authorizer and Payment Processor, do not need to know much about them selfs.

VCR

Configuration https://vcrpy.readthedocs.io/en/latest/configuration.html

Task 7 Connect to the url and assert the response content.

Convert the bytes content to json.

Decode and convert.

Assert the first element login and id.

Compare time with api response and without.

Use the url https://api.github.com/users/hadley/orgs.