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Here are things to know when preparing a Swift coding test for potential candidates.

As a Chief Technology Officer (CTO), one of your key responsibilities is ensuring that your software development team has the skills to deliver high-quality software. This often means testing the skills of your developers before they join your team, or as part of their ongoing professional development.

You also probably already know how vital it is to get the best candidates to apply for your job openings. And if you want to do that, you must ensure your application process is as clear and straightforward as possible.

Swift code test assignments are a great way to assess a developer’s knowledge of Swift. It’s also a great way to give your developers a chance to show off their skills.

If you're using Swift as your programming language of choice, then you'll need to prepare Swift code test assignments for potential candidates joining your team. Irmin Dzevlan, an iOS developer, shares his top five assessments to use when testing Swift developers.

Five suggested code test assignments for Swift

These assignments assess a candidate’s Swift programming skills and ability to solve real-world problems using Swift. Here are five suggestions you can use, which you are free to expand on in the test based on your business needs.

1. Weather App: App that displays current weather conditions for a given location. The app should display the current temperature, humidity, and wind speed.

2. Networking and APIs: App that uses an API, such as displaying a list of movies from a movie database or a weather app that pulls data from a weather API. The app should handle networking, parsing JSON data, and displaying the results in a user-friendly way.

3. Data persistence: Use some form of data persistence, such as Core Data or Realm, to store and retrieve data. The app could be a simple to-do list or a more complex one allowing users to track their workouts or expenses.

4. Multithreading and concurrency: Make use of multithreading and concurrency to improve performance, such as a photo gallery that loads images in the background or a messaging app that sends and receives messages asynchronously.

5. Object-oriented design: App that demonstrates great object-oriented design principles, such as encapsulation, inheritance, and polymorphism. The app could be a simple game or utility app that uses classes and structs to model real-world objects and their interactions.

Preparing for the test

Irmin shares why setting clear expectations is critical when preparing the test.

“Before you start creating a Swift code test, you must define the skills and knowledge you're looking for in your candidates. This means defining the scope of the test, the expected outcomes, and the level of expertise you require. Be sure to communicate these expectations to your developers so they know what's expected of them.”

author Irmin Dzevlan

He listed these below as essential to do as well:

Choose relevant topics

The Swift language is vast and covers many topics, from basic syntax to advanced topics like functional programming and concurrency. When preparing your test, make sure you're selecting topics that are relevant to your project and your team's skill level. For example, if you're building a mobile app, you might want to focus on UIKit, networking, and data persistence.

Provide clear instructions

Ensure the Swift code test instructions are clear and easy to understand. This includes providing precise requirements, code submission instructions, and other relevant details. It's also essential to give a timeline for completion so that developers know when to submit their work.

Create a rubric

Create a rubric or scoring system that outlines how you will assess the developer's performance on the coding challenge, including specific criteria such as functionality, code organization, readability, and adherence to best practices.

Use real-world examples

One of the best ways to prepare a Swift code test is to use real-world examples. Try to use real-world scenarios relevant to the job the developer will be doing, as this will help them demonstrate their skills in a more realistic setting.

It will also help developers understand how they can apply the skills they're learning in real-life scenarios. For example, if you're building an e-commerce app, you might ask candidates to implement a shopping cart feature.

Use online tools

There are many online tools available that can help you create and manage Swift code tests. These tools provide a range of features, from code editors to testing frameworks, that can help you streamline the testing process. Some popular tools include HackerRank, CodeSignal, and Codility.

Include a code review

Code review is an essential part of software development and should also be part of your Swift code test. This will help you assess the candidate's coding skills and ability to write clean, maintainable code. Provide feedback on the candidate's code and ask them to make improvements as necessary. In your feedback, include the areas where they excelled and could improve. This will help them learn from the experience and improve their skills for future opportunities.

If possible, consider collaborating with other developers or experts in the field to create or review the coding challenge. This can help ensure that it is accurate, relevant, and effective at assessing the candidate's skills.

Keep the challenge realistic

While it's essential to challenge the developer, it's also important to keep the coding challenge realistic and manageable so that they have a reasonable chance of completing the task within the given timeframe.

Allow adequate time for the developer to complete the coding challenge, taking into account any factors that may affect their ability to work, such as their current workload or time zone differences.

Things that are vital to test in Swift coding assignments

“Swift coding assignments can be a useful tool to evaluate candidates' skills and abilities in various areas, helping to ensure that they are a good fit for the position and have the necessary skills to succeed in the role.”

author Irmin Dzevlan

There are several important aspects that can be tested in Swift coding assignments. Irmin suggests the following:

  • Syntax and language fundamentals: It's crucial to test candidates on their understanding of the syntax and fundamental concepts of Swift, such as variables, data types, control flow, functions, and classes.

  • Problem-solving skills: Coding assignments can help assess a candidate's ability to break down complex problems into smaller, more manageable parts and develop effective solutions.

  • Attention to detail: Assignments can help evaluate a candidate's attention to detail and ability to write clean, organized, and maintainable code.

  • Familiarity with frameworks and APIs: Assignments can help assess a candidate's familiarity with common frameworks and APIs used in iOS app development, such as UIKit, Core Data, and Alamofire.

  • Object-oriented design principles: Swift coding assignments can help evaluate a candidate's ability to apply object-oriented design principles, such as encapsulation, inheritance, and polymorphism, to solve real-world problems.

Benefits of giving candidates real-world coding challenges to solve

Real-world coding challenges can be an effective tool to assess candidates and ensure that you hire the best individuals for the job.

“Real-world coding challenges can provide a more accurate assessment of a candidate's skills and abilities, as they simulate the type of work they will be doing on the job.”

author Irmin Dzevlan

Irmin lists the benefits below:

Demonstrating problem-solving skills

Allow candidates to demonstrate their problem-solving skills in a realistic setting, which can help assess their ability to tackle complex problems and develop practical solutions.

Providing a fair assessment

Provide a level playing field for all candidates, regardless of their educational background or previous work experience. This can help ensure that the best candidates are chosen based on their skills and abilities.

Showing commitment to the job

Demonstrate a candidate's commitment to the job and their willingness to go above and beyond to demonstrate their abilities and prove their worth.

Improving retention rates

By using real-world coding challenges to assess candidates, you can have peace of mind that you are hiring individuals who are well-suited for the job and are more likely to be satisfied with their role. This leads to better retention rates and less turnover.

Things to avoid

If you are responsible for assigning Swift code test assignments to your developers, there are certain things you should avoid doing while preparing them. Here are some things:

  • Don't give developers a Swift code test assignment without instructions or context.

  • Don't make up questions that are unrelated to Swift or Xcode.

  • Don't make up questions that could be answered by Google or Stack Overflow.

  • Don't make the assignment so ambiguous that it would take a long time to complete.

  • Don't make the assignment so simplistic that it wouldn't be challenging enough for developers to learn something new.

As Swift gains more traction among developers, companies increasingly seek talented developers proficient in the language. As a CTO, you play a critical role in ensuring that your development team has the skills to build high-quality Swift code. Swift code testing is essential to this process, and creating practical test assignments is vital to ensuring your team is up to the task.

It’s safe to assume that Swift will be integral to the Apple app ecosystem for years. When hiring Swift developers for your team, you must aim for them to create the best code possible. Give them all the resources they need, then check how they perform. Over time, your standards and expectations will evolve, growing more detailed and complex.

Following the five suggestions outlined in this article, you can design Swift code test assignments that are challenging, engaging, and informative. When preparing, remember to focus on practical, real-world scenarios and give your candidates the freedom to use their creativity and problem-solving skills. Doing so will help your team develop the skills they need to create robust, reliable Swift code that meets your business' and customers' needs.

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