function test snapshot
This function is called from snapshot, which implements the 'snapshot' phase of test processing. This is done right before the 'run' phase, and is intended to be used to capture information about the state of the machine that might help diagnose any errors found during a test.
If a test does not have have a test_snapshot function, then a default set of data is collected from the board (by calling the ov_rootfs_state function). If desired, this function may be called to get the default information, and then additional commands may be executed (usually with the cmd function, to retrieve additional snapshot data from the target._
This function can perform any operations on the host or board that are desired, to gather state information that might be relevant to the test. Each operation should append it's output to the file named by $SNAPSHOT_FILENAME.
Core interfaces and Variables)
$SNAPSHOT_FILENAME has the name of the snapshot file.
There are no arguments to this function.
An example path would be: /fuego-core/engine/tests/Functional.hello_world/fuego_test.sh (inside the Docker container)