Ideally, you should be following TDD principles, if you’re not familar with them then I recommend watching the following video from Uncle Bob. TDD can provide instant feedback on whether or not the code you’re writing is doing the correct thing, which can be very useful particularly in complex applications that are hard to test […]
Knowing what to test is difficult, but the important question you should always ask yourself is; “Am I just writing this test to increase the code coverage?” If the answer is yes, then chances are that test isn’t adding any value. Let’s look at an example I like to use; Here we have a custom […]
This post is the first in a series on the why, what and how of unit testing. It was originally going to be a single post but there was so much I wanted to cover it didn’t seem right to do it as a single post. For this post we’re going to look at why […]
Sometimes a unit test needs to do more than validate the good or correct path, what about failure scenarios? Let’s consider a search function, it returns an object when it finds what’s being requested but throws an exception when it can’t, any calling method would need to handle that exception and then behave accordingly. Here’s […]
Previously (here, here and here) we looked at users.py and how we can create a set of tests using mocks to validate it’s working as intended. The subject we were mocking in those previous examples was file_utils.py. Here’s what file_utils.py looks like; Very simple, one function writes to a file and the other one reads […]
Before reading this post I’d recommend reading my previous ones available here and here. In the previous tutorial we used unittest.mock to mock out our test subject’s dependencies, this simplified our tests and allowed us to focus on one piece of functionality at a time. Unfortunately the approach detailed previously has a drawback! Let’s make […]
This post follows on from a previous post, available here. I’d recommend giving it a read as we’re going to be building on that knowledge of Python’s unit test framework. In my previous post I gave examples of how to write simple unit tests and while that’s fine when your functions are that simple what […]
