dotdotdotpaul

dotdotdotpaul

Testing Elixir - MapSet.new vs. Enum.sort in unit test example

Title: Testing Elixir - MapSet.new vs. Enum.sort (p. 80 PDF)

The example on this page shows an assertion with the code:

code: assert Enum.sort(actual_fields_with_types) ==
       Enum.sort(@expected_fields_with_types)

But the previous code example (p.77) uses MapSet.New instead of Enum.sort:

code: assert MapSet.new(actual_fields_with_types) ==
       MapSet.new(@expected_fields_with_types)

Not sure which is better, TBH. :smiley:

Also while I’m here – p83, there’s a typo, attibribute should be attribute. :smiley:

…Paul

Marked As Solved

idlehands

idlehands

Author of Testing Elixir

Thanks @dotdotdotpaul! This is funny because I was using Enum.sort and Andrea was pushing for MapSet.new. I let him switch up the code sample (I wrote the majority of that chapter) and it looks like that led to some inconsistency. We will get fix it so that it used one or the other, but I will try to address the trade-offs here so you can decide which you prefer.

MapSet.new is fast and consistent, but, as @hauleth pointed out, it doesn’t allow duplicate entries. So… it honestly just depends on what you need. The thing that I tend to find myself doing is writing a single test assertion helper, called something like assert_unordered_lists_are_equal(lists, opts \\ []) and let the opts include :allow_dupes. Then, you have a clearly stated function and the implementation isn’t as important. In fact, depending on the options, you can do it in a different way. That only issue there, then would be slight inconsistency in the test output.

We don’t write a ton of helper functions in the samples, largely because the more complex or spread the code, the harder it is to fit on the page.

Again, thanks for catching the inconsistency. We’ll get that resolved, but ultimately, both solutions are just fine unless you need duplicates in your list.

Also Liked

dotdotdotpaul

dotdotdotpaul

Not sure if I submitted this right, LMK. :smiley:

hauleth

hauleth

Depends on what you want to test, as the behaviour of these is different in case of actual_fields_with_types = [1,2,1] and @expected_fields_with_types == [2, 1]

dotdotdotpaul

dotdotdotpaul

Yeah, I was thinking that myself, but either way, the text is inconsistent. Not sure if the intent was to switch back to Enum.sort and it didn’t get backported, or the intention was go forward with MapSet.new (which is actually described in the text as the method used) and wasn’t copied all the way through.

Where Next?

Popular Pragmatic Bookshelf topics Top

telemachus
Python Testing With Pytest - Chapter 2, warnings for “unregistered custom marks” While running the smoke tests in Chapter 2, I get these...
New
alanq
This isn’t directly about the book contents so maybe not the right forum…but in some of the code apps (e.g. turbo/06) it sends a TURBO_ST...
New
jeremyhuiskamp
Title: Web Development with Clojure, Third Edition, vB17.0 (p9) The create table guestbook syntax suggested doesn’t seem to be accepted ...
New
AndyDavis3416
@noelrappin Running the webpack dev server, I receive the following warning: ERROR in tsconfig.json TS18003: No inputs were found in c...
New
jskubick
I’m under the impression that when the reader gets to page 136 (“View Data with the Database Inspector”), the code SHOULD be able to buil...
New
adamwoolhether
I’m not quite sure what’s going on here, but I’m unable to have to containers successfully complete the Readiness/Liveness checks. I’m im...
New
brunogirin
When trying to run tox in parallel as explained on page 151, I got the following error: tox: error: argument -p/–parallel: expected one...
New
jonmac
The allprojects block listed on page 245 produces the following error when syncing gradle: “org.gradle.api.GradleScriptException: A prob...
New
davetron5000
Hello faithful readers! If you have tried to follow along in the book, you are asked to start up the dev environment via dx/build and ar...
New
dachristenson
I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...
New

Other popular topics Top

Devtalk
Hello Devtalk World! Please let us know a little about who you are and where you’re from :nerd_face:
New
New
AstonJ
I ended up cancelling my Moonlander order as I think it’s just going to be a bit too bulky for me. I think the Planck and the Preonic (o...
New
Exadra37
Oh just spent so much time on this to discover now that RancherOS is in end of life but Rancher is refusing to mark the Github repo as su...
New
mafinar
Crystal recently reached version 1. I had been following it for awhile but never got to really learn it. Most languages I picked up out o...
New
AstonJ
Continuing the discussion from Thinking about learning Crystal, let’s discuss - I was wondering which languages don’t GC - maybe we can c...
New
New
First poster: joeb
The File System Access API with Origin Private File System. WebKit supports new API that makes it possible for web apps to create, open,...
New
PragmaticBookshelf
Author Spotlight: VM Brasseur @vmbrasseur We have a treat for you today! We turn the spotlight onto Open Source as we sit down with V...
New
PragmaticBookshelf
Develop, deploy, and debug BEAM applications using BEAMOps: a new paradigm that focuses on scalability, fault tolerance, and owning each ...
New

Sub Categories: