Fredrik Teschke

I'm a freelance Elixir developer with
a passion for testing,
an eye for design and
a love of agile team work.

[Fredrik Teschke @aeftes]

phoenix_test_playwright v0.12.0 released 🥳
Shorthand to eval JS in browser, assert_path fixes for LiveView navigations, and more.
Also ships with https://t.co/68ep5ob2ZX for LLM coding agents. 🤖

#elixirlang

[Fredrik Teschke @aeftes]

Rewrote https://t.co/RaVKia5WBN from JS to Elixir 🎸 Free tool to convert music chordsheets (UltimateGuitar → ChordPro, etc.).
Ported ChordsheetJS to Elixir with Claude — surprisingly few manual interventions needed. Now on Phoenix and finally motivated to build new features!

[Fredrik Teschke @aeftes]

Playwright remote server support (websocket) for phoenix_test_playwright 🥳

Looking for early feedback — especially around CI setups.
"Remote server playbook" for the docs.

Please give the main branch a spin:
https://t.co/eWOGAAtnH5

Hat tip to Carson and Tyler!
#elixirlang

[Fredrik Teschke @aeftes]

phoenix_test_playwright 0.10.1 released 🥳

Small macro, big effect 🪄:
step/3 groups trace actions and AUTOMATICALLY links to source code line

Big thanks to @nathanl for adding this!

[Fredrik Teschke @aeftes]

TIL Oban's unique job period uses fixed time windows, not sliding windows.

A job with unique: [period: {7, :days}] can still allow duplicates 2 days apart if they fall into different buckets.

For sliding windows use a custom query.

https://t.co/x3fo3NUiaT
#elixirlang #oban

[Fredrik Teschke @aeftes]

🎉 phoenix_test_playwright 0.10.0-rc.0 released
Breaking changes - if you are reaching beyond the PhoenixTest API into internals.

Upside:
Browser pooling by default.
Well documented, consistent PlaywrightEx API for advanced use cases.

Early adopters ftw!

#elixirlang

[Fredrik Teschke @aeftes]

🎉 playwright_ex 0.2 released

Focus: documentation and consistency
Added docs and typespecs
Ensured API consistency, especially 'Channel' modules (browser, frame, ...)

#elixirlang
https://t.co/8MqLOyA7Z4

[Fredrik Teschke @aeftes]

Tinkering:
phoenix_test browser based tests with WebDriver bidi.

Using butterbee lib (#gleamlang).
https://t.co/EUlJLI2dea

#elixirlang

[Fredrik Teschke @aeftes]

I present: playwright_ex

A simple Playwright client for #elixirlang.
Experimental.
Extracted from phoenix_test_playwright.

PRs welcome!

It's not comprehensive, because that's a daunting task (see playwright-elixir).
But easy to extene

https://t.co/8MqLOyA7Z4

[Fredrik Teschke @aeftes]

#ElixirConfEU call for talks is open (Apr 23-24, Malaga).

I submitted: Changeset driven forms.

Interested?
Which aspects should I focus on? 👇

#elixirlang
https://t.co/F5mYEILb9A

[Fredrik Teschke @aeftes]

Call for feedback:
phoenix_test_plawright browser pooling

Please run locally & in CI.
Useful? Stable? Configurable to your needs?

https://t.co/hB7ijJSEWu

#elixirlang

[Fredrik Teschke @aeftes]

Surprising ⚡️:
Performance of phoenix_test_playwright already pretty good.
Compared to official javascript client.

Many tests: browser re-use (experimental) brings slight boost.
Unclear if worth the complexity.

Do you need it?
https://t.co/8OtP6O63hI

#elixirlang

[Fredrik Teschke @aeftes]

phoenix_test 💆
#elixirlang

[Fredrik Teschke @aeftes]

"Let it Crash - Designing Robust Systems"
Our talk included a Live Demo with audience participation.

👇 More details about what Marcus and I did at Dev Connect OWL.
https://t.co/1EDT0qkjlm
#elixirlang

[Fredrik Teschke @aeftes]

How do you find a misbehaving part of your software?

Patience 🤣
Monitoring & Metrics (Prometheus, Grafana, cAdvisor, PRTG)
Error Tracking & Logging (Sentry, Firebase, log files)
Observability & Tracing (OpenTelemetry, metrics, distributed tracing)
User Feedback

[Fredrik Teschke @aeftes]

We asked two questions at our talk "Let it Crash - Designing Robust Systems".

What are your building blocks for robust systems?
How do you find a misbehaving part of your software?

Great answers in thread👇
My takeaway: The BEAM provides.
#elixirlang #devconnectowl

[Fredrik Teschke @aeftes]

What are your building blocks for robust systems?

Testing & Monitoring (unit/load tests, monitor, health checks)
Fault Tolerance (redundancy, circuit breakers, loose coupling)
Simple Architecture (KISS)
Load Distribution (client-side calcs)
"I would ask you" 🤣

[Fredrik Teschke @aeftes]

PhoenixTestPlaywright 0.8 released

- speed up refute_has
- support bunx
- support phoenix_test 0.8

And other quality of life improvements.

#elixirlang

[Fredrik Teschke @aeftes]

Common phoenix pitfalls when upgrading to LiveView 1.1
Tests may break in several ways.

- HTML boolean attrs like 'checked' rendered differently
- stricter CSS selectors due to lazy_html
- phoenix_test needs fix #45 (unreleased)