My iOS Dev Courses (Swift, SwiftUI & UIKit) - seanallen.teachable.com

I'm at the point where I'm learning job-ready skills. unit testing was next on my list to tackle and Then the goat pops out with a video about unit testing.

Thank you Sean, you have a great ability of making any complex notion/concept into simple …keep going 👍

Straightforward and easy to grasp. Thanks I've been hearing about unit testing for years but didn't actually see it in action until now.

Thanks for the nicely explained summary! Easily the most straightforward explanation and example I’ve seen. Will look to adopt this at least partially into my apps.

thank you so much! I find your teaching style works for me so well, I'm so lucky and thanks a lot for your hard work and kindness to share

I enjoyed this topic, Its bout 9 months since I start writing tests for my code, and I think it is very important (if your code will not change in the soon future) because it makes you sure that your app has a solid foundation and you can be built more features upon it. Thanks Allen

I have a mobile app on the App Store. Unit tests didn’t make sense building the MVP. Now that it’s live, it’s so helpful knowing my tests pass before releasing an update. That’s why they make sense for me.

Thanks so much for this video! Now I really have very good visualization of unit tests and whether they are really important to me. Guess I will stick to my own simulator/device testing for the time being.

always happy to see a new video!!!

Crazy. I have just been listening to swift over coffee s1, listening to you talking about testing or lack of testing in some cases 😂

Thanks, Sean! Superb as always.

Thanks! Been waiting for this one.

Great intro to testing - really helped me get an idea of where to start. Thanks!! 🙂

This is coming at the right time. Just getting into testing. Thanks a lot Sean. Will we see other testing videos?

This is my first time looking into anything XCode tests related frameworks. I like it and a lot… I have read and/or entertained Test Driven Development (as a hobby, never in practice) and can get behind the benefits. There’s some functions that just get harder and tricky to test by having to launch the whole app constantly and getting to the state where the bug might or might not trigger… Those tests can run larger loops to test a lot of different numbers, file or directory paths (for me a pain to handle always no matter the language if it has to go through the whole UI to test), so on and so forth. What makes me wonder though, does XCode testing tools offer the possibility to simulate an environment? Let’s suppose our app needs to save to the Documents folder, so a test that finds the right folder and file name paths is understandable. And whether the app has access to the Documents folder enabled or not can be handled by an injected Boolean. But would it be possible to test the process of that? As in: “testSaveToFileAsksForDownloadsFolderAccess() -> void { // assert that this asks for download folder access if there’s no access available }”, or something like that where before when the test is run, macOS itself removes access to that.

Thank you for clear explanation 🙏

I've been coding a number of years and I really don't think any professional developer should deploy an app without at least about 10 % of something they have written having some form of unit testing. Even if its just we made the file did some set up and covered a single test case. Just enough to set up the foundation for adding more tests. I say this because I've found it's harder to add the very first test for code but once you get past that very first one. The rest are waaaaayyyyyy easier.

Fantastic - Unit Tests are exactly the sort of skill that employers are looking for experience in when interviewing for Junior iOS Devs (I’m finding!)

thanks Sean!

Do you have any plans to offer courses on unit testing in the future? Thank you for your video; it has been very helpful to me.

Another great video. I finally understand what those new folders that keep popping up on any new app that I make and why I need them. Sean, I wanted to ask, given that Xcode updates often and knowing they are requiring that all apps on the App Store are updated to Xcode 15 is that what are you using on your current apps, OR are you coding up to Xcode 17.2? Struggling to figure out how updated my app should be given users are not updating their devices as quickly as Xcode is being updated.

Thanks for the video. The `@testable import` helps resolve compiler time errors, but I still get build errors (linker errors). There must be something I need to place in the Build Setting to make this work. Furthermore, importing the entire app seems like overkill for really large projects.

Documentation and tests are the most neglected elements of software development, but are the most critical reasons why engineering teams begin to unravel as they scale. My suggestion, whether you are writing simple or complicated functions, over-document it with comments. What is each variable being declared, why does this conditional cause an early return, what outputs can we expect from this function. For tests, even when the team is small and scrappy, I recommend using them if your application has complex logic on the frontend. Granted, I always recommend putting business logic on the backend, but there is still a lot of frontend logic that determines UI state and navigation that is worth writing tests for. One example is if you have a list of lists, and there is some multi-select functionality that takes into account minimums and maximums, and auto-navigating to the next lists, write a test for it. General rule of thumb: documentation comment as you write, and if it is complicated for you to explain, then it deserves tests.

I've worked on embedded firmware for medical devices and unit testing is required. It's a very significant amount of work and unpleasant to boot. Other clients without FDA requirements rarely want to pay for unit testing, but our company did do some level of unit testing anyway to protect ourselves from unwanted surprises. Releasing code for manufacturing processes, for example, may not fall under FDA quidelines, but clients will still be very upset if something goes wrong. That said, one approach is to install unit tests in your project so that you have the infrastructure in place. Then when you do run into a bug, write unit tests to expose that bug. Then when you fix the bug you can be confident that a real world bug will not reappear some time in the future. You're probably covering some other bugs, as well. It also serves as a documented history of bug fixes.

Nice Video Sean.Please made a video on API Testing with mock data.

Unit testing is not just about finding errors it can be a useful tool to help design functions and can allow you to visualise data in terms of a function.

What are the state-of-the-art style for benchmarks in Swift?

When I try to create a target for testing it says none on targets to be tested and I can't figure out why it is not allowing me to select the main Target or any for that matter. Please help!!

Thanks!

Great code!

Thanks.

It’s really very useful video for developers, I followed all your playlists videos on time. Can you continue XCTestCases video using API calling.

🎉 awesome Sean

Hello I am new to Swift. As soon as I rename my unit test from "testAdd" to just for example "add" or simply something without the "test" prefix my test disappears. Is it necessary in Swift for tests to have the "test" prefix?

The test class will have access to the Calculation struct if it will be a separate file.

YESSS!!!!

Actually, regression tests literally mean “going back” and testing what you did before to make sure nothing broke,it’s not that you are preventing code breakage from regressing functionality.

I really miss mocks and swift makes cheap mocks impossible.

"Look! I designed this exotic vehicle that can reach over 100 Km/H! It's all done; it just needs to be tested. Do you want to drive it?" "Look! I built this building entirely from scratch, and it's all done! It just needs the calculations checked. Do you want to buy it?" Come on, guys! If you want to ensure that your work is correct, you need TO TEST IT, PLEASE! There is no such thing as "Everything is ready to go, just needs testing."

Why does it need a device to run a unit test? Seems so silly.

Unit testing is great (and important!)... We've added tests at my jobs, but now I need to figure out how to get my side app (which is using Core Data) to have some unit tests!