snapshot_power_test is a standalone test to simulate power failures during a snapshot-merge operation.
Start by creating two large files that will be used as the pre-merge and post-merge state. You can take two different partition images (for example, a product.img from two separate builds), or just create random data:
dd if=/dev/urandom of=pre-merge count=1024 bs=1048576 dd if=/dev/urandom of=post-merge count=1024 bs=1048576
Next, push these files to an unencrypted directory on the device:
adb push pre-merge /data/local/unencrypted adb push post-merge /data/local/unencrypted
Next, run the test setup:
adb sync data adb shell /data/nativetest64/snapshot_power_test/snapshot_power_test \ /data/local/unencrypted/pre-merge \ /data/local/unencrypted/post-merge
This will create the necessary fiemap-based images.
The actual test can be run via run_power_test.sh. Its syntax is:
run_power_test.sh <POST_MERGE_FILE>
POST_MERGE_FILE should be the path on the device of the image to validate the merge against. Example:
run_power_test.sh /data/local/unencrypted/post-merge
The device will begin the merge with a 5% chance of injecting a kernel crash every 10ms. The device should be capable of rebooting normally without user intervention. Once the merge has completed, the test will run a final check command to validate the contents of the snapshot against the post-merge file. It will error if there are any incorrect blocks.
Two environment variables can be passed to run_power_test.sh:
FAIL_RATE - A fraction between 0 and 100 (inclusive) indicating the probability the device should inject a kernel crash every 10ms.DEVICE_SERIAL - If multiple devices are attached to adb, this argument is passed as the serial to select (to adb -s).