Karlo Smid – Tentamen Software Testing Blog

Look ma, I have 20 million available oban jobs!

tl;dr In this post, I’ll describe how our team diagnosed and resolved a serious bottleneck when our Oban job queue grew to over 20 million jobs in the “ state—and…

Karlo Smid June 15, 2025

What I learned on Testival #68 Meetup

testival

**Testival #68 Highlights**

On November 11, 2024, Testival #68 brought together nearly 40 software testers at Njuskalo. Katarina’s presentation on Njuskalo’s “tribal” testing structure, supporting continuous delivery, sparked valuable discussions. As an Elixir team lead, I found the meetup an excellent opportunity to refresh testing skills and exchange insights during the networking session. Testival continues to be a key platform for professional growth.

Karlo Smid November 16, 2024

Could not check origin for Phoenix.Socket transport

elixir, phoenix

TL;DR I recently deployed a Phoenix LiveView application and encountered the infamous error: “Could not check origin for Phoenix.Socket”. The solution wasn’t immediately obvious, even with Phoenix’s excellent documentation. Therefore,…

Karlo Smid June 25, 2024

To Mock or not to Mock?

elixir, unit test

TL;DRThis weekend I attended CITCON2024 held in Zagreb. One session caught my attention, To Mock or not to Mock? Session author used some mocks in her unit testes, and wanted…

Karlo Smid May 30, 2024

Solution For Sluggish Erlang Observer

elixir

Erlang Observer Erlang observer is a great tool that helps you to get insights into your running BEAM node or a crash dump file of crashed BEAM node. It is…

Karlo Smid June 27, 2022

Testival Community Ending Scene

testival

“Attack ships on fire off the shoulder of Orion. I watched C-beams glitter in the dark near the Tannhäuser Gate. All those moments will be lost in time, like tears…

Karlo Smid December 2, 2021

Pattern matching trouble in ExUnit

elixir

TL;DR I found an interesting bug, not in the implementation code, but in the ExUnit test. The bug was related to Kernel.match? method. I will explain the root cause of…

Karlo Smid November 17, 2021

How To Log Invalid HTTP Request In Phoenix

elixir, phoenix

The Problem Our service built with Phoenix framework logged the following message: The source that recorded this error was the plug_cowboy function early_error. Logs are integrated with Datadog, otherwise, we…

Karlo Smid August 14, 2021

How To Use Elixir Gettext As A Team

elixir, phoenix

TL;DR You are working on a Phoenix application that uses Elixir Gettext for translations. As all team members are doing changes on translation files, you have a lot of merging…

Karlo Smid April 19, 2021

How To Set Up Your S3 Bucket With Custom Domain Name Parked At CloudFlare

AWS

TL;DR Your application stores files in S3 Bucket. The problem is that the URL to a file stored in S3 Bucket is under the AWS domain name, s3.amazonaws.com. In this post,…

Karlo Smid April 6, 2021

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Author: Karlo Smid

Look ma, I have 20 million available oban jobs!

What I learned on Testival #68 Meetup

Could not check origin for Phoenix.Socket transport

To Mock or not to Mock?

Solution For Sluggish Erlang Observer

Testival Community Ending Scene

Pattern matching trouble in ExUnit

How To Log Invalid HTTP Request In Phoenix

How To Use Elixir Gettext As A Team

How To Set Up Your S3 Bucket With Custom Domain Name Parked At CloudFlare

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