Target Preparers are invoked before the tests in the test level in which they are defined. This allows the setup of any device for tests to run smoothly.
Base interface
The base interface is
ITargetPreparer,
which allows implementation of a setUp
method that will be executed. We
recommend implementing our basic abstract class
BaseTargetPreparer,
which provides a built-in disablement feature to easily disable a preparer.
Cleaner interface
The natural extension of setUp
is tearDown
and is provided by a different
interface
ITargetCleaner. That provides the tearDown
interface
that allows cleaning up anything that was done in setUp
after the test
execution.
The BaseTargetPreparer
class also extends ITargetCleaner
.
Recommendations
We recommend each preparer be limited to a single main function, for example installing an APK or running a command. This allows for easier re-use of preparers.
You should also check the list of available preparers before adding a new one to avoid duplicating work. Preparers are available in tools/tradefederation/core/src/com/android/tradefed/targetprep/.
XML configuration
The object tag will be target_preparer
, for example:
<target_preparer class="com.android.tradefed.targetprep.InstallApkSetup">
<option name="install-arg" value="-d"/>
</target_preparer>
Also refer to Suite Setup for context.
Top-level setup
If specified in a top-level setup, the preparer will be run only once for each device. An example is cts-common.xml, which is a top-level setup for Android Compatibility Test Suite (CTS) tests.
Module-level setup
If specified at the module level, the preparer will always be run before that
module. An example is
backup/AndroidTest.xml,
which defines how Tradefed runs the backup
CTS module.
Note that while the preparer will run before the module, it will run after any System Status Checkers.