Black Box LAVA testing for Android

This module contains a collection of tools that run on an Android system and simplify the automation of tests. Android includes a lot of built-in tests but they differ in output formats and a way of executing them.

How to use

To use this software you need to incorporate it in your build. The best way to do that is to augment the manifest to pull code from the official github repository: git://github.com/zyga/android-lava-wrapper.git

For instance, to add it to one of the Linaro builds all I had to do was to patch the manifest with the following diff:

    diff --git a/landing-snowball.xml b/landing-snowball.xml
    index f3764b4..7d53aa1 100644
    --- a/landing-snowball.xml
    +++ b/landing-snowball.xml
    @@ -10,6 +10,8 @@
                fetch="git://git.linaro.org/" />
       <remote  name="android_input_bridge"
                fetch="git://github.com/rperier/" />
    +  <remote  name="android-lava-wrapper"
    +           fetch="git://github.com/zyga/" />
       <default revision="refs/tags/android-4.1.1_r4"
                remote="aosp"
                sync-j="4" />
    @@ -20,6 +22,7 @@
       <!-- External extras -->
       <project path="packages/apps/0xbench" name="platform/packages/apps/0xbench" revision="linaro-master" />
       <project path="external/android_input_bridge" name="android_input_bridge" remote="android_input_bridge" revision="master" />
    +  <project path="external/android-lava-blackbox" name="android-lava-blackbox" remote="android-lava-blackbox" revision="master" />
     
       <!-- Linaro extras -->
       <project path="packages/apps/DisableSuspend" name="platform/packages/apps/DisableSuspend" revision="master" />

Having done that run repo sync to fetch the new repository.

It is important to know that android-lava-blackbox runs only in builds made with TARGET_BUILD_VARIANT=tests. If in doubt have a look at my build scripts at http://github.com/zyga/android-build-scripts The configurations ending with -tests build the proper variant.

Once you have a build transfer it onto your device (make flash if you have used my build scripts) and get adb shell or direct serial shell to your device. You will need to run as root so you may need to use su first. This is also patched in Linaro builds.

To run all of the tests at once simply run:

$ lava-blackbox --run-all-tests

Observe the output as tests fly by to know where each one gets saved but in general all results will be saved to /sdcard/LAVA.

How to grab results

You can fetch each result with adb pull but ideally you will use lava-android-test to run this and obtain a single bundle directly.

This topic shall be extended as lava-android-test parts get written.

Which tests are supported

All of the tests that use the Google test framework are supported. Support for additional tests can be added in the future. You can add support for additional tests by simply shipping a wrapper finder that will identify new tests.

How it works

This tool, runs on an Android device, once triggered it requires no outside help to produce test results. It follows this simple algorithm to complete its task:

  1. Any file named *_test is considered a possible candidate
  2. Each candidate is offered to a subsequent wrapper-finders. Wrapper finders are small programs that are saved to /system/bin and follow a simple naming convention lava-wrapper-finder-*
  3. The first wrapper finder that offers a non-empty response wins. The text returned by the last wrapper finder is used to know which wrapper should be used to run the specified test
  4. The wrapper is started with the test name as argument and the -o option, to select the output file with the test results.
  5. The wrapper does whatever is needed to execute the tests, interpret the results and save the bundle to the requested file.
  6. The loop continues with subsequent test candidate to point 2

There are a few other things to know about:

  • The tool creates a directory to store all of the bundles. By default that is /sdcard/LAVA but it can be overridden on the command line. Inside that directory, each time the script runs, a new unique directory is created. Inside that directory, in turn, are all of the bundles created by subsequent wrappers.

  • The tool passes -r option to each wrapper to produce human readable output.

  • There is no way for two wrapper finders to offer support for a single test, if that happens the result is not deterministic and depends on the ordering of file system traversal.

  • If a test or test wrapper hangs the whole tool will hang as well.

Glossary

lava-blackbox: Main executable of this projnect that should be launched (on an Android device) to start testing.

wrapper finders: Small programs that help lava-blackbox to recognize valid tests and suggests which wrappers should be used to process that test. android-lava-wrapper ships with one wrapper finder by default, lava-wrapper-finder-gtest that recognizes certain gtest-based tests. All wrapper finders must be placed in /system/bin and must follow the naming convention lava-wrapper-finder-*

wrappers: Small utilities that can convert output of a certain kind of tests into the Linaro Dashboard Bundle format. Each wrapper has a standardized interface and must accept -o and -r options as well as a single argument that points to the test to execute. The wrapper must execute the test in any means necessary and create a bundle with the processed test results. android-lava-wrapper ships with lava-gtest-wrapper that knows how to execute and parse gtest-based tests.

Linaro Dashboard Bundle: A JSON-based data interchange format designed to store test results and rich meta-data. This format is consumed by the LAVA Dashboard. The format is documented at http://linaro-dashboard-bundle.readthedocs.org/

LAVA Dashboard: Part of LAVA that stores displays test results. You can think of it a big web-accessible archive. You can learn more about it at http://lava-dashboard.rtfd.org/