The challenge

Our client was a large international hotel brand and was suffering from extremely slow and unstable automated mobile testing for their business facing mobile app.

Our Approach

We partnered with the business and brought on our leading Solution Architect to analyze the current state of the automated Java mobile code. The code was in serious need of updating as it was using extremely old technologies with outdated testing methodologies. Over numerous months we worked with the customer to refactor the mobile test automation to work with Java, Junit, and Appium.

Script Atomic Tests

There’s no more important best practice to create a better and faster automation experience than to run atomic tests. These focus on just one piece of application functionality and are much faster and easier to execute than longer tests assessing multiple pieces of functionality.

Let’s examine what this looks like in practice. Suppose an online retailer needs to validate that users can log in, view their gift card balance, add items to their cart, proceed to checkout and successfully process a transaction. Even an experienced tester will often make the mistake of scripting a single test to validate those five functions. The far better approach, especially if the aim is to reduce run time and improve test quality, is to write five separate tests, each specifically focused on one piece of functionality. Running individually but in parallel, these five “atomic” tests will execute in far less time than one longer test.

Run Tests in Parallel

Of course, if those five atomic tests are executed sequentially—that is, one at a time, one after the other—they’ll take even longer to complete than the one screen flow test, negating any potential runtime benefit. That’s why running tests in parallel is an equally critical component of any strategy to reduce test run times. Consider the hypothetical example of a test suite with 100 atomic tests, each of which takes two minutes to execute. Run those 100 tests sequentially and they’ll take more than three hours to complete. Run them in parallel, and all 100 will complete in just two minutes.

Remember, too, not to get thrown by the volume of tests in a given suite. It’s tempting to think that a suite with 10 long tests that each take 5 minutes to complete will execute faster than one with 100 atomic tests that each take 1 minute to execute. But even if executed in parallel, the suite with the 10 long tests will still take 5 minutes to run—five times longer than the suite with 100 atomic tests.

Reduce the Number of Selenium Commands

Having too many Selenium commands in your test script flies in the face of atomic testing and is one of the most common underlying causes of long and unstable tests. Every single command takes time to execute and represents a new opportunity for something to go wrong. Minimize the number of commands required to execute a test case and run time will shrink accordingly.

Use Explicit Waits

Another effective way to reduce test run time is to use explicit waits rather than implicit waits. Implicit waits set a default wait time between each step or command across a test script, such that the subsequent step only executes after the pre-defined amount of time has elapsed. Explicit waits, on the other hand, enable the next step in a script to execute as soon as the preceding step is complete. Though more complicated to implement, using only explicit waits can have a significant positive impact on test run time.

Putting it Together

The example below shows an unoptimized test suite with 311 commands run against a mobile device. This example took 1,265 seconds (or more than 21 minutes) to execute. If delivering better software faster is the aim, that’s not going to work.

Applying the aforementioned tactics to the same test suite executed against the same device, however, drove the total number of commands down to just 127 and enabled the suite to execute in just 430 seconds (or just over 7 minutes), a 66% improvement in test run time.

Though the prospect of reducing test run time may be daunting, by focusing on a limited set of key tactics and best practices, the end goal of shorter, more stable tests is indeed attainable.

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