4 Steps to Improve Your Test Coverage

Sarah Mischinger

September 11, 2019

It’s no secret that you need to provide your users with highly functional and robust apps to stay relevant. And you know that you need to test your products to achieve that goal. But how can you measure your testing efforts? Your app test coverage tells you whether you are testing enough and where there’s room for improvement. Although wide test coverage doesn’t guarantee the release of bug-free apps, it helps you a great deal with this endeavor. Follow these 4 steps to improve your test coverage and provide your users with more robust and enjoyable mobile products.

What is Test Coverage?

Test coverage measures how much of your application you test. And it’s not only about how many tests you perform. It’s also about what real devices, browsers, and operating system versions you review! The more possible devices and operating system combinations you test, and the more code your tests cover, the higher your test coverage.

Note, that it is unrealistic to achieve 100% test coverage. In general, it may be enough for you to reach 70%. Additionally, achieving higher test coverage may take more time and delay your app launch. To determine the right number, you must assess your needs and analyze the risks associated with lower test coverage. After careful evaluation, you can make a safer bet about how much test coverage you need to publish a stable and reliable application.

If you know the test coverage of your app, you can also find the neglected parts in your code that you don’t test. As a result, you get new ideas on how to increase test coverage and reduce the risk of releasing malformed applications. Additionally, you can better estimate the time and cost and allocate resources more efficiently. And what’s not to like about that?

Now, you may be wondering how to improve your test coverage. How can you get the most out of your team’s testing time and deliver satisfying mobile apps to your audience? Let’s get you started with the following four tips to increase your application’s test coverage.

#1 Create a Plan and Set a Goal

You can’t improve your test coverage without having a plan. You need to define various aspects of your testing strategy, so your team knows what to do and when.

For example, you should define the devices, operating systems, and OS versions on which you want to run your tests. Be sure to update this list when new devices and operating system versions are released, and older ones disappear from the market. Also, consider what’s popular with your users! Focus on testing what your actual customers use to provide them with an outstanding experience with your product. In short, you need to define your app test device coverage.

But there’s more to think about and plan! How often do you test? Do you also examine how your app behaves under different real-world conditions? For example, do you apply different network connectivity profiles?

Always take into account how much time these tests will take, and whether you can afford it. In the end, you often have to weigh potential risks against available resources to decide what and how regularly something should be tested.

Note, though, that even 100% test coverage does not mean releasing flawless products! That’s why you should never stop testing – even post-release.

Lest not forget: You also need a goal that you can work towards! How much test coverage does your app need? Define a percentage of your test device coverage and code coverage your testers need to reach before your team can release the app to your users. Continue working on your strategy and evaluate the results. Analyze what works and what doesn’t, streamline your plan accordingly, and get your team on the same page. In this way, you can gradually increase your test coverage!

#2 Increase Code Coverage

Traditionally, many software development teams like to define their test coverage through their code coverage. Code coverage is determined by how many lines of code a component has and how many of these lines get executed in test cases.

The formula you need to apply to calculate the code coverage looks like this:

(Code lines executed by tests / total code lines) * 100 = code coverage in percent

You may be wondering how you can know about your code coverage. Typically, if you use a Continuous Integration tool, you can run code coverage against all your code. The result of this operation will give you an excellent insight into the status quo. Your team can then create a plan of action, allowing them to improve code coverage by writing missing tests.

Usually, the goal should be at least 80% – the higher, the better. The more tests you perform for your components, the less undetected bugs are awaiting your users. However, keep in mind that code coverage doesn’t tell you anything about other essential criteria like code quality! So don’t rely on code coverage alone to ensure the release of high-quality apps.

#3 Enhance Test Automation

You know the deal: Test automation lets you perform more tests in less time. Relying on only manual testing leads to bottlenecks and slows down your time-to-market. Continuous integration and continuous deployment with test automation help you identify errors and bottlenecks in your product early in the development lifecycle. Besides, by automating repetitive test cases, your team can focus on more exciting and challenging tasks.

Depending on your test requirements, of course, test automation may not be a feasible option to achieve the expected results. In general, we’ve seen some common use cases where manual testing on real devices is a better option. For example, you need to manually test whether your app looks and feels right to ensure that the user experience is spot-on.

However, most times, you can bet on automation for other testing scenarios, such as repetitive tests or test that expects a specific result.

Most likely, you have already automated a good portion of your tests. To improve test coverage, try to automate wherever it’s possible and feasible. As a result, you can use the gained time to test on more devices or increase your code coverage.

#4 Test on a Larger Scale

As described in one of our previous articles, you can get even more out of your automated test setup by testing on an unlimited number of devices at the same time.

Running automated tests takes time – the more sophisticated a test case, the longer it takes. Think about it: If you run your automated tests on one device at a time, you won’t publish your app for a while. This circumstance worsens if you want to achieve high device coverage!

To ensure timely publication, you need to conduct your tests on a larger scale. You need to use an environment in which you can test an unlimited number of devices simultaneously. As a result, you can conduct as many combinations of devices and operating system versions as needed in the shortest possible time.

And again, you can use the time, saved by testing on as many devices as possible, elsewhere. For example, you could increase your test device or code coverage, perform more necessary manual tests, and so on.

Bonus: Increase Test Coverage by Running Tests with a Cloud Test Service

Your customers expect your app to run smoothly and error-free. To make sure to live up to these expectations, you need to deploy stable and functional products. Creating a testing strategy and defining your desired test coverage help you with that.

Track your performance and see if you can improve your app test coverage with the four tips presented in this article. We wish you good luck!

However, to get the best out of your plan, you need a suitable infrastructure for testing. You need an environment where you can improve and reach your test coverage goals. Why not give Bitbar’s device testing cloud a shot? Use your favorite testing frameworks, perform automated and manual tests, and enjoy unlimited device concurrency.