webcodr goes Netlify CMS

Until today posts on webcodr were published via a simple git-based workflow. If I wanted to create a new posts, I had to open the repository in Visual Studio Code and created a markdown file. After pushing the commit with the new file, a GitHub hook notified Netlify to pull the repo and build and publish the site.

It was quite simple and effective, but lacks comfort and does not work on iOS/iPadOS devices. After buying a new iPad Air and Magic Keyboard, I wanted a pragmatic way to write posts without my MacBook or PC.

I always wanted to try Netlify CMS, so this was my chance. The transition was really simple. I followed the guide for Hugo-based sites and adjusted the config to work with Hugo. That‘s it. Netlify CMS works just fine with the already existing markdown files. Even custom frontmatter fields within the markdown files are no problem, just set them up in the config file.

A little more configuration in the Netlify admin panel is necessary, but the guide explains everything very well. It was just a matter of 15 minutes to get everything going.

If you use a static site generator and want to have a little more comfort, Netlify CMS makes it really simple. They provide guides for every major player like Gatsby, Jekyll or Nuxt and of course Hugo. You don‘t even have to use GitHub. GitLab and BitBucket are supported as well. As are more complex workflows for more than one editor, custom authentication with OAuth or custom media libraries.


Netlify CMS supports markdown and has a basic, but decent editor with rich-text mode. But I wanted a little bit more, so I decided to write my posts in Ulysses — a specialized writing app with support of GitHub-flavored markdown, including syntax highlighting preview . It‘s available for macOS and iOS/iPadOS. All files and settings are synched via iCloud. So, once you have setup everything, you‘re good to go on any of your Apple devices.

Since Ulysses requires a subscription, I will use this to „force“ me writing more posts. 😁

I wrote this post entirely on my iPad Air and so far, I‘m quite happy with the new workflow. Of course I will not write every post this way. New posts with code examples will be easier to handle on a Mac or PC. (Hey Apple, how about IntelliJ on an iPad?)

btw: even as an enthusiast of mechanical keyboards I have to say, it‘s quite nice to type on a Magic Keyboard. I just have to get used to the smaller size. The Magic Keyboard for the 10.9“ iPad Air or 11“ iPad Pro is a compromise in size and some keys like tab, shift, backspace, enter and the umlaut keys (bracket keys on english keyboard layouts) are way smaller compared to normal-sized keyboards. It‘s bigger brother for the 13“ iPad Pro has a normal layout, but that monster of an iPad seems a bit excessive for my use case.

Kotest and JUnit with IntelliJ or: don’t frak up your toolchain upgrades

My team and I recently decided to use Kotlin for new features in our existing project. It was a great choice to implement a new authentication process and we’re now rewriting some older parts of the application from Java to Kotlin.

Actually I wanted to use Kotlin for a while now, but there were only minor tasks within the Java part of the project. That finally changed and we can focus to improve the Java backend drastiscally.

Part of this process was a library update. We decided to upgrade JUnit from 4 to 5. A big pain in the ass. I don’t think, I would do it again. JUnit 5 was also part of a bigger problem, even if it was actually PEBCAC.

Kotest and MockK features

If you already know about Kotest or want to know more about the problem I had, just skip to next headline. The Kotest introduction is a little bit longer.

As I dived more and more into Kotlin, I stumbled over a Kotest. A really neat testing framework for Kotlin. There’s nothing wrong with JUnit, but Kotest gives you way more awesome ways to structure your tests.

A little example:

package io.webcodr.demo

import io.webcodr.demo
import io.kotest.assertions.throwables.shouldThrow
import io.kotest.core.spec.style.FunSpec
import io.mockk.*

class UserServiceTest : FunSpec() {
    private val userRepository = mockk<UserRepository>()
    private val service = UserService(userRepository)
    private lateint var user: User

    init {
        beforeTest {
            user = User(1, "Jane", "Doe", "[email protected]")

        afterTest {

        context("getUser()") {
            fun verifyRepoCalls() {
                verify {


            test("should succeed") {
                every {
                } returns user



            test("should fail") {
                every {
                } throws UserNotFoundException()

                shouldThrow<UserNotFoundException> {


Kotest offers serveral different styles to write tests. I chose the FunSpec style for this example. You could also use a BDD-like or Jasmine-like style, if you want to.

It’s much more intuitive to nest tests with Kotest. To be fair, JUnit 5 allows you to use @Nested with an inner class to acomplish nesting as well, but it’s not as intuitive and harder to read than trailing lambdas.

Assertions are also a little easier to write. Kotest has over 100 different matchers. You can use them as extensions functions, like in the example above or alternatively as infix functions, for example service.getUser(1) shouldBe user. It’s also quite simple to write custom matchers.

There are many more features like soft assertions, tagging, easy temporay file creation or handling for non-deterministic test cases.

For mocking we decided to use MockK, since it’s way more intuitive to use than Mockito with Kotlin. Don’t get me wrong, Mockito is a great library, but it has one flaw: the when method. when is a keyword in Kotlin and to use it with Mockito, you need to write it in backticks. That’s quite ugly and not intuitive at all.

So, in summary, Kotest offers a bunch of pretty neat features and is very intuitive to use. Of course, JUnit can achieve much of this as well, it’s just not that shiny and little harder to read.

The actual problem or: why the frak is there IntelliJ in the title?

If you migrate an old codebase to Kotlin and want to use Kotest, you will have no choice and have to use JUnit and Kotest in coexistence.

That shouldn’t be a problem, since Kotest uses the JUnit 5 Jupiter engine under the hood. But …

As I wrote a new service in Kotlin and some tests with Kotest, I could not start the JUnit tests anymore. As soon as the maven depedency of Kotest was present, IntelliJ didn’t recognize JUnit tests and used the Kotest files only. With mvn test (Maven Surefire) everything worked fine.

I tried several things and was ready to give up. Search engines didn’t find anything about this problem. Nothing on GitHub, nothing on Stack Overflow.

I hate to give up, so I decided to create a small demo project to open a GitHub issue. Well, that didn’t work out as intended, since the discovery of JUnit tests in the demo project worked fine. The IntelliJ JUnit runner did what it was supposed to: run JUnit and Kotest.

Well, frak. There must be some kind configuration problem with my real project. I already looked at the IntelliJ runner config, Maven files etc. — nothing worked.

I compared the Maven files from both codebases and there was one difference: my real project did not include the JUnit Jupiter Engine depedency. Bingo. I added to the Maven file and guess what? It worked like a charm.

What an embarassment. As we upgraded from JUnit 4 to 5, we forgot to add the new depedency for the engine. I don’t know why the tests worked at all, but it seems the engine is not really necessary for all cases. But it can screw up test discovery quite well, if you forget it.

The dependency configuration in POM file should like this:


Well, that was a long post, but IMO it was necessary to show how this problem came to be and even if you have no trouble at all, perhaps you’ll consider to use Kotest. It’s awesome!


I’m not sure, but this issue could happen with Gradle as well, when you are migrating to JUnit 5.

macOS Catalina EDID Override AKA HDMI color fix

HDMI connections from your Mac to monitor can be a pain in the ass. There is a chance that macOS will detect your monitor as a TV and set the color space to YCbCr. You will get wrong colors and sometimes blurry fonts.

If you’re having this problem, like me, you know the fix: a patched EDID created with this little Ruby script.

The installation of this EDID override could be tedious since the release of El Capitan, as SIP won’t let you access the necessary system files. Just disable it in recovery mode, copy the file and enable it again. Sucks, but works just fine.

Now, Catalina is out for a few hours and has a new way to annoy people who need EDID overrides. All system-related directories and files are read-only, regardless of the status of SIP.

Fortunately Apple was not crazy enough to disable the write access completely.

Help is on the way, ETA 0 seconds!

  1. Patch your EDID
  2. Boot into recovery mode with CMD+R
  3. Login with your user
  4. Open Disk Utility, select your volume (in most cases Macintosh HD) and mount it with your password (yes, again)
  5. Close the Disk Utility and open a Terminal window
  6. Copy the directory with the patched EDID to /Volumes/$VOLUME_NAME/System/Library/Displays/Contents/Resources/Overrides
  7. Reboot and enjoy the right colors again

Here’s an example of the shell commands:

cd /Volumes/Macintosh\ HD/System/Library/Displays/Contents/Resources/Overrides
cp -rf /Volumes/Macintosh\ HD/Users/webcodr/DisplayVendorID-5a63 .

Don’t forget to use the correct volume and user names!

Dear Apple

Just add a simple solution to select the HDMI color space. A simple shell commando with sudo would suffice or at least let us use an override directory within the user library as it was possible many years ago. It just sucks to do this after every macOS upgrade and every time you improve system security, it gets harder.

Please, don’t forget us powers users …

Hello, Dark Mode

Dark mode for Android and iOS? Hold my beer …

It’s quite simple to implement. Every modern browser can evaluate media queries in JavaScript with window.matchMedia() and supports CSS variables.

I added the following to my application JavaScript file:

const preferColorSchemeResult
  = window.matchMedia('(prefers-color-scheme: dark)')

if (preferColorSchemeResult && preferColorSchemeResult.matches === true) {
  document.documentElement.setAttribute('data-theme', 'dark')
} else {
  document.documentElement.setAttribute('data-theme', 'light')

The script will set the data attribute theme on the document element (html) with the possible values dark or light depending on the result of the media query.

There’s no need for a polyfill, even IE 10 supports window.matchMedia()

Stylesheet changes is even simpler, since I already had introduced SCSS color variables a while ago. I just had to replace them with CSS variables.

// colors
$c_white: #fff;
$c_dark-grey: #4A4A4A;

:root {
  --container-background-color: #{$c_white};

[data-theme="dark"] {
  --container-background-color: #{darken($c_dark-grey, 20%)};

That’s basically it. If you use SCSS, please take notice to use interpolations to map the SCSS variables to CSS variables. This change in SassScript expressions was necessary to provide full compatibility with plain CSS.

Since the theme selection is fully automated, I will provide a toggle possibiliry in a future release for those of you who prefer the light mode. This can be easily achieved with a flag in local storage and some minor changes in the JavaScript part.

Snapshot Tests With Jest

Writing tests can sometimes be a tedious task. Mocks and assertions can be a pain in the ass. The latter is especially nasty when HTML is involved. Give me the second p element from the 30th div within an article in aside etc. – no thanks.

The creators of Jest (Facebook) have found a better way: Snapshot tests!

How does it work?

Take a look the following assertion:

it('should create a foo bar object', () => {
  const result = foo.bar()

toMatchSnapshot() takes what ever you give to expect(), serializes it and saves it into a file. The next test run will compare the expected value to the stored snapshot and will fail if they don’t match. Jest shows a nicely formatted error message and diff view on failed tests.

This is really useful with generated HTML and/or testing UI behaviour. Just call the method and let it compare to the snapshot.

Updating snapshots

You added something to your code and the snapshot has to be updated? No problem:

jest --updateSnapshot

If you’re using the Jest watcher it’s even simpler. Just press u to update all snapshots or press i to update the snapshots interactively.

What about objects with generated values?

Here’s an example with an randomized id:

it('should fail every time', () => {
  const ship = {
    id: Math.floor(Math.random() * 20),
    name: 'USS Defiant'


The id will change on every test run, so this test will fail every time. Well, shit? Nope. Jest got you covered:

it('should create a ship', () => {
  const ship = {
    id: Math.floor(Math.random() * 20),
    name: 'USS Defiant'

    id: expect.any(Number)

Jest will now only compare the type of the id and the test will pass.

For certain objects like a date, there is another possibility:

Date.now = jest.fn(() => 1528902424828)

A call of Date.now() will call the mock method and always return the same value.

Some advice

  1. Always commit your snapshots! If they are missing,CI systems will always create new snapshots and the tests will become useless.

  2. Snapshot tests are an awesome tool, but don’t be too lazy. They are no replacement for other assertion types, especially if you’re working test-driven. Rather use them alongside with your other tests.

  3. Write meaningful test names. Well, you heard that one before, didn’t you? Really, it helps a a lot when tests fail or you have to look inside a snapshot file. Jest takes a test name as an id inside a snapshot file. That’s why you have to update a snapshot after changing the name.