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Android "L" and UiAutomator command line shenanigans

Wow! It has been a long time since I've updated this blog; so long, in fact, that I a whole new version of Android has been announced (okay maybe 2 or 3). Like many of you, I was paying very close attention to the live streamed sessions at this year's Google I/O. At first I thought L contained nothing new for my QA interests but upon further digging I found a few tiny gems:

"You can execute shell commands from your instrumentation test with the new The command execution is similar to running adb shell from a host connected to the device. This allows you to use shell based tools such as dumpsys, am, content, and pm."

Oh that's nice.  I guess that means I don't need these anymore:
-     public static void runShellCommandStringArray(String[] command) throws IOException {
       try {..
-     public static void runShellCommandString(String command) throws IOException {
       try {...

My current project uses Google Tag Manager to provide packaged test configurations for use when launching the app so I'd been using these for launching the app via various intents depending on the test scenario. I'd also been using these to stop the app and clear it between test case executions in my setUp() and tearDown() calls to make sure that each test case can and will be run independently from a clean state.

Now, because reasons, I am planning on using this kind of trick to launch screenrecord and capture a video of the events in my UIAutomator tests, discarding the results for all passing tests and archiving test-case-method-named captures for all failed tests to allow for a sort of replay by testers and developers looking into the results from any given test runs (obviously this takes up space and carries the 3-minute limitation to screenrecord but none of my tests yet run 3 minutes or longer). When used in conjunction with “Show Touches” enabled in the developer settings, recording tests helps to debug failures by capturing exactly what happened from the user’s point of view, including all the steps leading up to the failure. My plan is to implement this in a similar fashion to the way that I previously implemented the screenshot on failed test routine found here in my post, Boom! Screenshot!

So let’s look at the specific code for how you can implement running shell commands from within your test cases. Then we’ll look at example calls to these commands in your test code given the scenarios I’ve described above. This gist is essentially a copy of some code I dug up on (whose URL I’ve lost or I’d reference it for further discussion if you wanted to follow up). I can’t recommend that resource highly enough for this kind of stuff. I mine it for gold regularly.

So as an example you might like to call am force-stop ** and pm clear ** during setUp() to ensure that each test starts from a clean slate. That would look like:

public void setUp() throws Exception {
runShellCommandString(“/system/bin/am force-stop”);
runShellCommandString(“/system/bin/pm clear”);

And finally let’s say you want to start your test by launching your app via Google Tag Manager (like the cool kids do). That would look a little like this:

public void testLaunchWithGoogleTagDemo() throws UiObjectNotFoundException, IOException {
//Do cool stuff like set UiWatchers and other test prep

//Launch app using Google Tag Manager because we’re cool kids
String command = "/system/bin/am";
String subcommand = "start";
String action = "android.intent.action.VIEW";
String urlData = gtmUrl;
Log.d(LOG_TAG, "My gtmUrl is " + gtmUrl);
String flagData = "0x14000000";

String[] gtmLaunchStringArray = new String[] {command, subcommand, "-a", action, "-d", urlData, "-f", flagData, "-W" };



So those are some examples of how to use shell commands inside your test code and why doing so is sometimes useful. There are many other opportunities for awesomeness which is why Google have added support for it directly. Happy testing!


  1. This comment has been removed by the author.

  2. This method cannot be used with the latest Uiautomator 2.0 correct? What can we do in 2.0 to clear cache and cookies before each test run?

  3. Im able to run this command in Uiautomator 2.0...but it breaks with a "UiAutomation Disconnected" error when a UiWatcher kicks in...have you seen this problem?


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