July 26, 2023

Top Test Coverage Metrics for Flawless Apps

Mobile Application Testing
Accessibility Testing

"What should I be testing now?”

If you or other members of your team have asked this question, you are not alone. Quarter by quarter and year by year, the digital landscape shifts and the app your team has worked so hard on must shift with it. Otherwise, you risk falling behind the times and losing users.

With new devices, market updates, OS releases, there is a lot to keep up with. Determining the combination of these factors to test against is the bedrock of your testing strategy. That is not even taking into account yet-to-be-released updates and releases! 

Test coverage metrics are important to consider. In this blog, we break down what test coverage metrics are, why test coverage analysis is important, and the latest test coverage trends that you should be aware of.

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What Is Test Coverage in Software Testing?

Test coverage means your tests are covering things like test requirements, code, different user scenarios, and platforms such as mobile devices or browsers. It is a useful metric for measuring the effectiveness of your testing efforts. Test coverage is important for finding defects before they reach users.

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What Are Test Coverage Metrics?

Test coverage metrics are used to measure and monitor your testing activity. By helping your team answer important questions such as the number of bugs found and the amount of time it takes to test, test coverage metrics also help you improve the testing process and maximize efficiency.

Test coverage metrics help you improve the testing process and maximize efficiency.

You can use test coverage metrics to get the answers to important questions, like:

  • How much of the software was tested?
  • How many bugs did the test team not find?
  • How long will it take to test?
  • Am I testing against the right environments/platforms?

But which test coverage metrics matter? Perfecto publishes a comprehensive mobile and web test coverage guide annually to help you understand. 

This index includes:

  • The latest annual web and mobile release calendar.
  • Our proven methodology.
  • The phones and browsers most used by your audience.
  • Insights from countries across North America, Asia, and Europe.

Latest Test Coverage Guide

Get your copy of the latest test coverage index today.

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Continuous Improvement Through Test Metrics

You can’t iterate and improve upon your tests without a reliable set of test metrics. Without them, you have no guideposts to know whether your tests are even giving you the information you need.  

Measuring test success through test metrics allows teams to know where improvement is needed. This information can then be reapplied through the engineer’s perspective to create and foster a culture of continuous improvement.

An important consideration when leveraging test metrics is to make sure teams are looking at the impact of and whether the current processes being implemented are successful. Properly used test metrics will illuminate where you need (and are able) to take your testing further.

The tricky thing about test metrics, however, is subjectivity can bleed into them if you let it. Think about whether you are measuring or assessing your testing process. Metrics can always be gamed depending on how you want to view them, so having actionable metrics and data associated with them to drive strategic decision-making is the way to improve — as opposed to a framework that looks or feels good.

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How to Measure Test Coverage

There’s a simple formula often used to measure the percentage of code test coverage. Divide the number of lines of code all test cases currently execute by the total lines of code in the software you are testing.

In addition to code coverage metrics, it’s important to look into covering the right test scenarios. This provides the highest value from a feedback perspective as well as the right target platforms (web and mobile). These two considerations are two sides of the same coin.

Ensure that you get the right test coverage metrics by testing the right scenarios.


As part of each group mix, the following attributes should be considered:

  • Device and OS popularity, including Custom OS versions  (market share).
  • Screen sizes, resolution, and other screen attributes such as pixel per inch (PPI).
  • Device age (launch date).
  • New and trending devices and platforms.
  • Operating system version update rate (e.g., reference devices like Android Pixel get a higher score).
  • Unique device properties important for testing purposes — chipset, CPU, memory.
  • Audience demographics.

The second and third groups offer the highest test coverage and the least risk to digital teams.

You should also have an ongoing process of refreshing your test lab. This is usually done on a quarterly basis, to make sure nothing major has changed in your user base or in the market that would require a new device or OS.

Learn about using tools to secure and optimize processes at scale with Perforce's enterprise automation 101 >>

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The Increasing Importance of Accessibility Testing

Accessibility testing is quickly becoming one of the most vital aspects of any testing strategy. When apps are in development, accessibility is now a regular factor with the definition of “done” — the same way functional correctness and security scanning are viewed.

The importance of being able to run accessibility tests at scale and at will cannot be overstated.

To assist you with improving the accessibility of your applications, Perfecto provides integration with the mobile platform accessibility tools Accessibility Inspector (iOS) and Accessibility Scanner (Android). With these tools, you can check the current screen of an application for accessibility issues. In other words, these tools run accessibility audits per screen, not on the entire application.

And Perfecto always keeps an eye toward innovation — we will be offering accessibility test integration with voiceover and talkback accessibility testing soon. 

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Ensure Comprehensive Test Coverage With Perfecto

Test coverage doesn’t need to be daunting. With Perfecto, you’ll get the tools and tips you need to ensure test coverage — for every metric.

Perfecto’s cloud-testing platform gives you access to all of the devices, platforms, and browsers that you need to test your app on. You’ll be able to use this cloud-based lab to ensure proper test coverage for your devices, platforms, and user conditions.

Get started today with a free 14-day trial.

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This blog was originally published on June 3, 2022. It has since been updated with new information.

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