Today, we started running Robocop and xpcshell tests in an Android x86 emulator environment on tbpl.
Firefox for Android has been running on Android x86 for over a year now  and we have had Android x86 builds on tbpl for nearly as long , but our attempts to run test suites on Android x86  have been more problematic. (See  to get an appreciation of the complications.)
This is the first of our Android test jobs to run in an emulator (Android 2.2 test jobs run on Tegra boards and Android 4.0 jobs run on Panda boards). The Android x86 tests run in Android x86 emulators running Android 4.2. The emulators run on Linux 64-bit in-house machines, and we run up to 4 emulators at a time on each Linux machine.
The new tests are labelled “Android 4.2 x86 Opt” on tbpl and look like this:
Each “set” contains up to 4 test jobs, reflecting the set of emulators that are run in parallel on each Linux box. For now, only set S4 is run on trunk trees; S4 contains xpcshell tests and robocop tests, broken up into 3 chunks, robocop-1, robocop-2, and robocop-3:
Other test suites – mochitests, reftests, etc – run on Android 4.2 x86 Opt only on the Cedar and Ash trees at this time. They mostly work, but have intermittent infrastructure failures that make them too unreliable to run on trunk trees (bug 927602 is the main issue).
If you need to debug a test failure on this platform, try server support is available, or you can borrow a releng machine and run the mozharness job yourself.