Android Studio 3.0 and FLAG_TEST_ONLY
AndroidManifest.xml file can have an
This value then shows up in
This has been around since API Level 4, which is practically forever in
Android terms. According to what little docs we have,
it serve as:
Option to indicate this application is only for testing purposes. For example, it may expose functionality or data outside of itself that would cause a security hole, but is useful for testing. This kind of application can not be installed without the INSTALL_ALLOW_TEST flag, which means only through
On the whole, this may seem unremarkable, considering that few people have remarked on it since it was introduced in 2009. However, there are two things to note about it:
You cannot install an app with
android:testOnly="true"by conventional means, such as from an Android file manager or from a download off of a Web site
Android Studio 3.0 sets
android:testOnly="true"on APKs that are run from the IDE
For many developers, this is of little consequence. However, if you have ever
taken an APK lying around your
build/ directory and sent it to somebody,
that will only work if you did something other than run the app in
Android Studio in order to create that APK, such as:
Built the app using the “Build APK(s)” menu option
Built the app using the
Built the app using something else that might use those tasks, such as a CI server
If, instead, you ship the APK that Android Studio built just by you running
the app, the APK cannot be installed normally.
adb install, for example, will report:
Failed to install app-debug.apk: Failure [INSTALL_FAILED_TEST_ONLY: installPackageLI]
adb install -t will install such a test-only app, however.
I don’t really have a problem with Android Studio 3.0 adding this flag. After all, the APK that you run from the IDE may bear little resemblance to the APK that your users will use (hello, Instant Run!). Using this flag to steer developers towards shipping APKs built by other means is fairly reasonable.
Unfortunately, this change is not covered in
the Android Studio 3.0 release notes,
the Android Studio 3.0 migration document.
It is mentioned in
the “Build and Run Your App”
page, though the docs there do not mention the need for the
So, just make sure that when you send an APK to somebody, you built it by some means other than just running it from Android Studio.