2020 Year in Review
What I've been up to in 2020...
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Exhaustiveness Checking with Mypy
What if mypy could warn you about possible problems at "compile time"? In this article I share a little trick to get mypy to fail when a value in an enumeration type is left unhandled.
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The Surprising Impact of Medium-Size Texts on PostgreSQL Performance
Any database schema is likely to have plenty of text fields. In this article I demonstrate the surprising impact of medium-size texts on query performance.
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Simple Anomaly Detection Using Plain SQL
Many developers think that having a critical bug in their code is the worse thing that can happen. Well, there is something much worst than that: Having a critical bug in your code and not knowing about it! Using some high school level statistics and a fair knowledge of SQL, I implemented a very simple anomaly detection system.
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Some SQL Tricks of an Application DBA
Some tips and misconceptions about database development I gathered along the way.
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Stop Using datetime.now!
If you ever had a test that one day just started to fail, unprovoked, or a test that fails once every blue moon for no apparent reason, it's possible your code is relying on something that is not deterministic. In this article I describe a practical approach to dependency injection in Python that when used correctly, can eliminate nondeterminism and make your code easier to maintain and to test.
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How to Move a Django Model to Another App
In my latest article for RealPython I cover some exotic migration operations, many of the built-in migration CLI commands and demonstrate important migrations concepts such as reversible migrations, migration plans and introspection.
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Testing an Interactive Voice Response System With Python and Pytest
It can be very challenging to test a system that rely heavily on a third party service such as Twilio. In this article, I show how to organize your code in a way that would isolate your bushiness logic and make it easier for you to test it separately.
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How to Provide Test Fixtures for Django Models in Pytest
One of the most challenging aspects of writing good tests is maintaining test fixtures. Good test fixtures motivate developers to write better tests, and bad fixtures can cripple a system to a point where developers fear and avoid them all together. The article covers everything from setting up Pytest for a Django project, creating test fixtures and how to create dependency between fixtures.
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Using Markdown in Django
How we developed a Markdown extension to manage content in Django sites.
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