Intro to Python Mocks #2: Mocking Exceptions | Python tutorial

This video is the second part of Python testing using Mocks series (or just Python Mocks). In this video we'll touch the mocking of exceptions topic, how to mock exceptions in Python, how to mock the .raise_for_status() function of the Requests library.
In this Python testing tutorial as an example I use a function that makes a request to external API. And as a testing library I use unittest.
It's a Python unittest mock tutorial for beginners.

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Timecodes:

00:00 - Beginning. Adding try/except block to the function under test
02:19 - How to raise an exception from a test, and how to mock an exception using the .side_effect property.
04:23 - Fixing the 'TypeError: catching classes that are not inherit from BaseException is not allowed' when mocking an exception.
07:03 - Using the .raise_for_status() function from the requests library
09:48 - Writing a test to test raise_for_status(), and mocking raise_for_status
13:32 - Checking status codes within an except clause of the try/except block.

Why Python mocks are important:
- Mocks eliminate dependency on network, database calls, calls to OS (it will speed testing)
- we get isolated unit tests,
- we can test methods that have no return value
- reduce test complexity. We don't have to write complex logic to handle behavior of methods under tests.
- don't have to wait to implement other methods.

When should you mock?
When you don't want to actually call an object

#1 Intro to Python Mocks | Python tutorial

#2 Intro to Python Mocks: Mocking Exceptions | Python tutorial

#python #testing #redeyedcoderclub

[RedEyedCoderClub]

What video should I make next? Any suggestions?
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Timecodes:

00:00 - Beginning. Adding try/except block to the function under test
02:19 - How to raise an exception from a test, and how to mock an exception using the .side_effect property.
04:23 - Fixing the 'TypeError: catching classes that are not inherit from BaseException is not allowed' when mocking an exception.
07:03 - Using the .raise_for_status() function from the requests library
09:48 - Writing a test to test raise_for_status(), and mocking raise_for_status
13:32 - Checking status codes within an except clause of the try/except block.

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[zakchips]

Great. Thanks a lot. Very useful and underestimated topic, especially for those who's just found a job as a developer. Looking forward for more.

[charlietodd]

This is a great start to my journey. Security note: the nose module is no longer being maintained and should not be used. Use nose2 if you must, but the preference is to move to pytest.

[serg_D]

Satisfied with your explanations for the lesson. I have not met a better explanation.

[brahimboughanem]

I want to thank you. I was really struggling to grasp the concept of mocking subjects, and your videos have made it so much easier for me to understand

[zzygyx]

awesome video. Thanks! Just wonder why in the end you used nosetests.

[ДанилКочетков-ыв]

This is an interesting video. For more of these in YouTube 👍👍👍

[ВладимирШалун]

Great video. Everything is clear and accessible.

[oliveratkinson]

Learn with your help the possibilities of Python Mock, get acquainted with the Requests library, using functions is a good opportunity to broaden your horizons and professionalism

[ОльгаЛебедева-цв]

Thank you. Your video helped me figure everything out.

[ВиталинаСмоленск]

Everything is smart and understandable. Thank you for the video.

[passhabi]

Why keep using MagicMock instead of Mock?

[МаринаПеткова-ум]

Great video tutorial and explanation. Thank you for the wonderful material.

[ЛарисаАфаринова]

It's something with something. 👍👍👍

[Инна-хк]

This information is really useful to me.

[olyfomina]

Great job thanks for it, your video lesson helped me a lot!! Good luck to you!!!

[kostya]

Thank you very much for the interesting and informative video.

[liliaharchikova]

Cool. Everything is clear and understandable.

[АнтонинаХохлова-сн]

it was interesting, thanks for the video.

[vanderfed]

Two comments about the code presented:

1. It's a very bad practice to use structures like "except SomeException: pass". That's how you can make exceptions untraceable and very difficult to debug.
2. If you mock not "main.requests" but "main.requests.get" you can get rid of all the fuzz about mocking raise_for_status. It is so much better to mock actually what you need to mock specifically than the whole requests library