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Day: January 20, 2023

Designing Test Code for shinytest2

Published 2023-01-20 by Kevin Feasel

Russ Hyde wraps up a series on shinytest2:

UI-driven end-to-end tests require a bit more code than unit tests. For example, starting the app and navigating around to set up some initial state will require a few lines of code. But these are things you’ll likely need to do in several tests. As you add more and more test cases and these commonalities reveal themselves, it pays to extract out some helper functions and / or classes. By doing so, your tests will look simpler, the behaviour that you are testing will be more explicit, and you’ll have less code to maintain. We’ll show some software designs that may simplify your {shinytest2} code.

This post builds upon the previous posts in the series, but is quite a bit more technical than either of them. In addition to shiny development, you’ll need to know how to define functions in R and for the last section you’ll need to know about object-oriented programming in R (specifically using R6). The ideas in that section may be of interest even if you aren’t fluent with R6 classes yet.

Click through for the series finale.

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Emulating Window Functions in MySQL 5.7

Published 2023-01-20 by Kevin Feasel

Lukas Eder says, we have window functions at home:

One of MySQL 8’s biggest improvements is the support of window functions. As I always said in conferences, there’s SQL before window functions and SQL after window functions. Once you start using them, you’ll use them everywhere.

Some of you poor souls are unfortunate enough to be stuck on MySQL 5.7, either of your own choosing, or because you’re using a clone / fork that is still 5.7 compatible. While for most people, this blog post is just for your amusement, or nostalgia, for some of you this post will be quite useful.

If you are in a windowless world, read on to see how you can make life a little more manageable.

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Performance Comparing DISTINCT to GROUP BY

Published 2023-01-20 by Kevin Feasel

Reitse Eskens does a performance comparison:

A few days ago, I heard someone stating that Group By was much quicker than Distinct. Less disk impact, less memory etc.
So, I thought I’d find out if it’s true or not because I found it interesting. I always thought there was no difference. I tested a single small table and found no difference in speed, reads or execution plan. But that’s no real world example. Usually the tables contain a lot of data and are joined to other tables.

Click through for the results of Reitse’s analysis.

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An Overview of the Power BI REST API

Published 2023-01-20 by Kevin Feasel

Reza Rad takes a look at Power BI’s API:

You can interact with the Power BI objects in the Power BI Service through a set of APIs called Power BI REST API. The Power BI REST API can help automate tasks, build tools that work with Power BI, the configuration of Power BI outside of the platform, and embed Power BI into a third-party application. In this article and video, I’ll explain REST API, why it is useful, and a few examples.

Click through for the video and explanation.

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Good Practices for Powershell Development

Published 2023-01-20 by Kevin Feasel

Jeff Hicks shares some good practices with us:

Over the course of the last several weeks, I’ve been sharing and demonstrating techniques for writing effective PowerShell functions. I know I’ve mentioned a few recommended best practices. But since they are important, I want to review and re-emphasize them. These practices will make your code easier to write, easier to debug or troubleshoot, and more secure. I’d like to think some of them are simple, common sense, but sometimes we need someone to remind us. These items are not in any particular order.

There are some Powershell specifics here but most of the advice is language-agnostic.

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Creating a Multi-Function Powershell Module

Published 2023-01-20 by Kevin Feasel

Patrick Gruenauer builds a module:

In this blog post, I will show you how to create a module with multiple functions using an example. You will see that this is not rocket science. Let’s jump in.

In order to use multiple functions in a module, we have to declare them as functions to export. This also means we need a module manifest file with that statements in it.

Read on to see what it takes to build a module in Powershell.

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