Dave Schweisguth in a Bottle

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Archive for the ‘Testing’ Category

Using and testing automatic accessors and virtual attributes of ActiveRecord models

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An ordinary ActiveRecord model object has an attribute for each column in its table. Each attribute has a reader method and a writer method. However, ActiveRecord also defines accessors on the fly to hold non-column query results. Also, sometimes it’s useful to define a new attribute, one not corresponding to a column or even to a field in a query result. These different kinds of extra attributes can interfere with one another, making them tricky to use and test. The best defense is to understand all of them well before using any of them. Let’s have a look.

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Written by dschweisguth

August 11, 2016 at 09:44

Posted in Programming, Rails, Ruby, Testing

Controlling database usage in RSpec and factory_girl, part 2: association strategy and unstubbed queries

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An important part of testing a Rails application is establishing the correct relationship between the specs of each layer and the database. To correctly test the layer that they test, some types of specs (model and feature specs) should run against the database; other types should not. As well as ensuring correctness, policing database usage optimizes performance: tests that use the database are slower.

This post, part 2 in a two-part series, describes two measures that you can take to minimize incorrect and unnecessary database usage in RSpec specs that use factory_girl.

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Written by dschweisguth

June 21, 2014 at 15:45

Posted in Programming, Rails, Ruby, Testing

Controlling database usage in RSpec and factory_girl, part 1: Choosing and allowing appropriate strategies

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When testing each layer of a Rails application, it’s important to create test model instances in the right way for that layer. Some specs need model instances that have been saved in the database, or that appear to have been; others need instances that have not. It’s also important to not use the database when you don’t have to, because every use makes your tests take a little bit longer.

This post, part 1 in a two-part series, lays out the appropriate use of factory_girl in specs of each layer of Rails, and gives a way to enforce that usage.

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Written by dschweisguth

June 21, 2014 at 12:27

Posted in Programming, Rails, Ruby, Testing

Dark corners of unit-testing lore

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The software community’s understanding of developer testing (unit testing, acceptance testing, etc.) has come a long way since “Extreme Programming Explained” and “Refactoring” and JUnit got everyone interested almost fifteen years ago. There was a time when developers argued whether unit testing was valuable (never mind TDD); now it’s taught in code camps as an essential skill.

But some testing techniques have remained out of the mainstream, for whatever reason. A couple of them came up on Stack Overflow recently and I was inspired to give long answers. Whether or not these techniques eventually become part of standard practice, they’re interesting to know about and possibly useful in shaping your thinking about mainstream practices.

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Written by dschweisguth

June 3, 2014 at 14:13

Posted in Java, Programming, Testing

How I spent my working vacation

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While at Fandor (still the finest independent and international film streaming service) I had almost no time for personal projects, but I did manage to write a few blog posts on Fandor’s late engineering blog, “Behind the Fan Door” (as my Fandor doppelgänger, fandave). These fit the best with my own interests and the rest of this blog:

Also, the idea of data testing is interesting, although its context in that post is less so. And, for completeness, here’s every single one.

[2017 update: “Behind the Fan Door” is gone, so I’ve replaced links to it with links to archived copies on my own site. Links in the copies are, unfortunately, mostly broken.]

Written by dschweisguth

March 2, 2014 at 08:31

Posted in Programming, Testing

Succinct specs for Rails named routes

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I like all of my routes tested, and I like all of my routes named, and I like all of my named routes tested. I even like to test my RESTful routes; even though it feels a bit like testing Rails, it more than paid for itself when migrating to Rails 3. How, then, to spec a named route succinctly?

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Written by dschweisguth

May 11, 2011 at 08:48

Posted in Programming, Rails, Ruby, Testing

Rails’ named routes considered helpful

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The current Rails best practice is to use RESTful routes. One nice thing about a RESTful route is that it comes with a name. Similarly, :member and :collection routes are automatically named. But sometimes you need a plain old arbitrary route, which you can then name or not as you wish. It may seem like overkill to give every route a name, especially if the route is referred to infrequently in templates. But there’s another place where you’re virtually guaranteed to need that named route again: in tests.

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Written by dschweisguth

May 11, 2011 at 08:36

Posted in Programming, Rails, Ruby, Testing