Test-driven ios development with swift 3 download

In addition to this, you want immediate feedback that is, a failing test whenever new code breaks a seemingly unrelated feature. Immediate feedback means that your memory of the changes that broke the feature is fresh, and the fix is made quickly.

To run one specific test, you can click on the diamond visible next to the test method:. When you click on it, the production code is compiled and launched in the simulator or on the device, and the test is executed. There is another way to execute exactly one specific test. When you open the Test Navigator and hover over one test, a circle with a play icon is shown next to the test method name:.

The test framework identifies tests by the prefix of the method name. If you want to run all tests but one, remove the test prefix from the beginning of this test method name. In the same way as running one specific test, you can run all the tests of a specific test case.

Click on the diamond next to the definition of the test case, or click on the Play button that appears when you hover over the test case name in the Test Navigator. You can choose to run a group of tests by editing the build scheme.

To edit the build scheme, click on Scheme in the toolbar in Xcode, and then click on Edit Scheme Then, select Test , and expand the test suite by clicking on the small triangle. On the right-hand side, there is a column called Test :. The selected scheme only runs the tests that are checked. By default, all the tests are checked, but you can uncheck some tests if you need to.

But don't forget to check all the tests again when you are finished. As an alternative, you can add a build scheme for a group of tests that you want to run regularly without running all tests.

We have already seen the setUp and tearDown instance methods earlier in this chapter. The code in the setUp instance method is run before each test invocation. In our example, we used setUp to initialize the View Controller that we wanted to test. As it was run before each test invocation, each test used its own instance of ViewController. The changes we made to this particular instance in one test didn't affect the other test.

The tests executed independently of each other. The tearDown instance method is run after each test invocation. Use tearDown to perform the necessary cleanup. In addition to the instance methods, there are also the setUp and tearDown class methods. These are run before and after all the tests of a test case, respectively.

Sometimes, but usually rarely, you may need to debug your tests. As with normal code, you can set breakpoints in test code. The debugger then stops the execution of the code at a breakpoint. You can also set breakpoints in the code that will be tested to check whether you have missed something or whether the code you'd like to test is actually executed.

To get a feeling of how this works, let's add an error to a test in the preceding example and debug it. Have you seen the error that we have introduced? The value of the string expectedOutput has a typo. The letter s in iS is an uppercase letter, and the letter i is a lowercase letter. The test fails and Xcode tells you what the problem is.

But for the sake of this exercise, let's set a breakpoint in the line with the XCTAssertEqual function. Click on the area on the left-hand side of the line where you want to set a breakpoint. You have to click on the area next to the red diamond. As a result, your editor will look similar to what is shown here:. Run the tests again.

The execution of the tests stops at the breakpoint. In the console, some test output is visible. The last line starts with lldb and a blinking cursor.

Put in po expectedOutput and hit return. The term po in the code indicates the print object. The console prints the value of expectedOutput :.

To learn more about the debugger, search for lldb in the Apple documentation. For now, keep the typo in expectedOutput as it is, but remove the breakpoint by dragging it with the mouse from the area to the left of the editor.

Xcode has a built-in breakpoint on test failures. When this breakpoint is set, the execution of the tests is stopped, and a debug session is started whenever a test fails.

Usually, this is not what you want in TDD because failing tests are normal in TDD, and you don't need a debugger to find out what's going on. You explicitly wrote the test to fail at the beginning of the TDD workflow cycle. But in case you need to debug one or more failing tests, it's good to know how this breakpoint is activated.

Open the Debug Navigator :. Click on it, and select Test Failure Breakpoint :. As the name suggests, this breakpoint stops the execution of the tests whenever a test fails. We still have a failing test in our example. Run the tests to see the breakpoint in action. The debugger stops at the line with the assertion because the tests fail.

Like in the preceding example, you get a debug session so that you can put in LLDB commands to find out why the test failed. Now, let's fix the error in the tests and learn how to run the previous test again. The test still fails. Fix it by changing iS to Is in expectedOutput. The shortcut is especially useful when you are working on one specific feature, and you need to test whether the implementation is already enough. You only write code that is needed : Following the rules, you have to stop writing production code when all your tests pass.

If your project needs another feature, you need a test to drive the implementation of that feature. The code you write is the simplest code possible. So, all the code ending up in the product is actually needed to implement the features. More modular design : In TDD, you concentrate on one micro feature at a time. And as you write the test first, the code automatically becomes easy to test. Code that is easy to test has a clear interface.

This results in a modular design for your application. Easier to maintain : As the different parts of your application are decoupled from each other and have clear interfaces, the code becomes easier to maintain. You can exchange the implementation of a micro feature with a better implementation without affecting another module. You could even keep the tests and rewrite the complete application. When all the tests pass, you are done. Easier to refactor : Every feature is thoroughly tested.

You don't need to be afraid to make drastic changes because if all the tests still pass, everything is fine. This point is very important because you, as a developer, improve your skills each and every day.

If you open the project after 6 months of working on something else, most probably, you'll have many ideas on how to improve the code. But your memory about all the different parts and how they fit together isn't fresh anymore. So, making changes can be dangerous.

With a complete test suite, you can easily improve the code without the fear of breaking your application. High test coverage : There is a test for every feature. This results in high test coverage. High test coverage helps you gain confidence in your code. Tests document the code : The test code shows you how your code is meant to be used. As such, it documents your code. The test code is sample code that shows what the code does and how the interface has to be used.

Less debugging : How often have you wasted a day to find a nasty bug? How often have you copied an error message from Xcode and searched for it on the Internet?

With TDD, you write fewer bugs because the tests tell you early on whether you've made a mistake. And the bugs you write are found much earlier. You can concentrate on fixing the bug when your memory about what the code is supposed to do and how it does it. No silver bullet : Tests help to find bugs, but they can't find bugs that you introduce in the test code and in implementation code.

If you haven't understood the problem you need to solve, writing tests most probably doesn't help. It seems slower at the beginning : If you start TDD, you will get the feeling that it takes longer to make easy implementations. You need to think about the interfaces, write the test code, and run the tests before you can finally start writing the code. All the members of a team need to do it : As TDD influences the design of code, it is recommended that either all the members of a team use TDD or no one at all.

In addition to this, it's sometimes difficult to justify TDD to the management because they often have the feeling that the implementation of new features takes longer if developers write code that won't end up in the product half of the time. It helps if the whole team agrees on the importance of unit tests. Tests need to be maintained when requirements change : Probably, the strongest argument against TDD is that the tests have to be maintained as the code has to. Whenever requirements change, you need to change the code and tests.

But you are working with TDD. This means that you need to change the tests first, and then make the tests pass. So, in reality, tests help you to understand the new requirements and implement the code without breaking other features. What should be tested? When using TDD and following the rules mentioned in the previous sections, the answer is easy—everything. You only write code because there is a failing test. In practice, it's not that easy. For example, should the position and color of a button be tested?

Should the view hierarchy be tested? Probably not; the color and exact position of the button are not important for the functioning of an app. In the early stages of development, these kinds of things tend to change. With Auto Layout and different localizations of the app, the exact position of buttons and labels depend on many parameters.

In general, you should test the features that make the app useful for a user and those that need to work. The user doesn't care whether the button is exactly 20 points from the rightmost edge of the screen.

All the user is interested in is that the button does what they expect it to and the app looks good. In addition to this, you should not test the whole application in total using unit tests. Unit tests are meant to test small units of computation.

They need to be fast and reliable. Things, such as database access and networking, should be tested using integration tests, where the tests drive the real finished application. Integration tests are allowed to be slow because they are run a lot less often than unit tests. Usually, they are run at the end of the development before the application is released, or they are run with the help of a continuous integration system each night on a server, where it doesn't matter that the complete test suite takes several minutes or even hours to execute.

In this chapter, we saw unit tests in action and how they are set up in Xcode. You learned what TDD is and why it can help build better apps. With the help of TDD, we implemented a feature of a demo app to get used to the workflow. We saw many different possibilities to run tests and how we can find bugs in our tests using LLDB, the debugger integrated into Xcode. Finally, we discussed the advantages and disadvantages of TDD and what should be tested with unit tests.

While working as a university professor, he started iOS development in his spare time. His first app on physics has been an astounding success worldwide. Since then, he has turned himself into a full-time iOS developer, with a number of successful apps to his name. He has been a Swift developer since day one and runs a blog on iOS development.

About this book Test-driven development TDD is a proven way to find software bugs early. Publication date: October Publisher Packt. Pages ISBN Download code from GitHub. Chapter 1. Your First Unit Tests. Building your first automatic unit test. What are unit tests? Implementing a unit test example. This method is called First, an array of characters is defined containing all the vowels in the English alphabet. Tip Note that without the [Character] type declaration right after the name of the constant, this would be created as an array of strings, but we need an array of characters here.

Finally, numberOfVowels is returned. Important built-in assert functions. Understanding TDD. You are not allowed to write any production code unless it is to pass a failing unit test You are not allowed to write any more of a unit test than is sufficient to fail, and compilation failures are failures You are not allowed to write any more production code than is sufficient to pass the one failing unit test.

The TDD workflow - red, green, and refactor. Tip Don't skip this step. TDD in Xcode. An example of TDD. Precondition : None. Red - example 1. Green - example 1. Refactor - example 1. Red - example 2. Green - example 2. Split the string into words. Remove the last space and return the string. Tip Do not skip refactoring. Refactor - example 2. Tip As you can see here, a failing test does not stop the tests in general. A recap. Finding information about tests in Xcode.

Test Navigator. Tests overview. Learn how to identify hard dependencies. Reshape the design of your code quickly, with less risk and less fear.

This book not only shows you how to code in a clean and concise manner, but also the why behind the code. Understanding why will be instrumental in your advancement as a Swift developer. The secondary audience is developers who have experience in iOS and Swift and want a good reference book for concepts they might already know, but are looking to re-enforce. You'll learn about unit testing, mocking and continuous integration and how to get these key ingredients running in your Swift projects.

This book also looks at how to write your Swift apps using test driven development TDD. Done correctly, Agile development results in a significant increase in development efficiency and a reduction in the number of defects. Apple has released unit testing and code coverage frameworks for Swift development in XCode.

Up until now getting unit testing up and running in Swift was not for the faint-hearted. Thankfully now, there is no excuse other than a lack of information on where to get started.

What You Will Learn Write unit tests in Swift Write an application using test driven development Examine GUI testing, refactoring, and mocking frameworks Set up and configure a continuous integration server Measure code coverage Who This Book Is For Swift developers and would be mobile app testers will benefit from the guidance in this book.

Fully updated to cover the latest features in iOS 14, this practical guide will help you get up to speed with writing iOS apps from scratch. First, this approachable text covers the fundamentals of Swift by introducing you to iOS development in this language, and presenting best practices for setting up a development environment and using variables, statements, expressions, operators, functions, and closures. Next, you explore common tasks, such as alert views, table views, and collection views.

You then deepen your knowledge of Swift by considering network programming and local data storage. Finally, this engaging resource dives into slightly more advanced concepts, such as tab bars, web views, the accelerometer, camera, photo library, Google maps, and core location.

Swift was designed by Apple to incorporate modern scripting features while offering simpler, cleaner syntax than Objective-C to maintain a minimal and easy to read style. This more expressive code offers numerous key features, such as closures unified with function pointers, tuples and multiple value returns, generics, and functional programming patterns. Learn how to obtain a device UDID Test your applications on an actual device, so you can see your work in action Distribute your applications outside of the App store, allowing you to test your work with real users Review common reasons why apps are rejected by Apple to strengthen your case when submitting your apps for distribution iOS Swift Hour Trainer is an essential guide to Apple's Swift programming language for beginning programmers.

Inside, you'll be guided through every step of the process for building an app, from first idea to App Store. This book fully covers Swift 4, Xcode 9, and iOS 1. Our video course, iOS Development with Swift in Motion, is the perfect companion to this book, featuring even more projects and examples for you to dig into in the exciting world of iOS development. Find out more at our website: www. About the Technology One billion iPhone users are waiting for the next amazing app. It's time for you to build it!

Apple's Swift language makes iOS development easier than ever, offering modern language features, seamless integration with all iOS libraries, and the top-notch Xcode development environment. And with this book, you'll get started fast. It takes you through the experience of building an app—from idea to App Store. After setting up your dev environment, you'll learn the basics by experimenting in Swift playgrounds.

Then you'll build a simple app layout, adding features like animations and UI widgets. Along the way, you'll retrieve, format, and display data; interact with the camera and other device features; and touch on cloud and networking basics. No prior experience with Swift assumed. About the Author Craig Grummitt is a successful developer, instructor, and mentor.

His iOS apps have had over , downloads combined! You'll have everything you need to create your very own apps for the latest iOS devices. Every single sample app in the book has been rebuilt from scratch using the latest Xcode and the latest bit iOS 8-specific project templates, and designed to take advantage of the latest Xcode features.

Assuming little or no working knowledge of the new Swift programming language, and written in a friendly, easy-to-follow style, this book offers a complete soup-to-nuts course in iPhone, iPad, and iPod touch programming.

The book starts with the basics, walking through the process of downloading and installing Xcode and the iOS 8 SDK, and then guides you though the creation of your first simple application. You'll start with the basics, and then work your way through the process of downloading and installing Xcode and the iOS 10 SDK, and then guides you though the creation of your first simple application.

Assuming little or no working knowledge of the Swift programming language, and written in a friendly, easy-to-follow style, Beginning iPhone Development with Swift 3 offers a comprehensive course in iPhone and iPad programming. Every single sample app in the book has been rebuilt from scratch using the latest Xcode and the latest iOS specific project templates, and designed to take advantage of the latest Xcode features. Discover brand-new technologies, as well as significant updates to existing tools.

This book will help you gain a solid understanding of Swift programming using focused recipes for building Swift apps efficiently. The author assumes you have no experience in app development.

The book starts with the installation of the required programming environment and setting up the simulators. Then, the simplest Hello World app is developed step by step. In the next chapter, basics of the Swift 3 programming language are given with practical examples. Screenshots and code snippets are clearly given in the book to guide the reader.

After the Swift lecture, 7 complete apps including a 2D game are developed in seperate chapters. Chapters of the book and the contents of these chapters are as follows: Chapter 1. Introduction: General info and the steps of developing an iOS app. Chapter 2. Chapter 3. Test drive - the "Hello World" app: Creating a new Xcode project, adding and positioning user interface objects, building the project, running the developed app on the simulator and on the real device.

Chapter 4. Swift programming language: Variables, constants, optionals, arrays, dictionaries, sets, if-else and switch-case decision making statements, for and while loops, functions, classes, objects and inheritance in Swift 3. Each concept is clearly explained step by step with code examples and screenshots. Chapter 5. Disco lights app: Using buttons and connecting actions to buttons in the code. Writing tests before your code improves the structure and maintainability of your apps.

In combination with the improved syntax of Swift 3, there is no excuse or writing bad code. This book will help you understand the process of TDD and how it impacts your apps written in Swift. Through a practical, real-world example app, you'll start seeing how to implement TDD in context. You will begin with an overview of the TDD workflow and then deep dive into unit testing concepts and code cycles.