CircleCI enginecore tests do not complete

[ylei-tsubame]

Python BDD behave scenarios under build-enginecore fail with

Failed to write data to connection Address(host='localhost', port=7687) (Address(host='127.0.0.1', port=7687)); ("0; 'Underlying socket connection gone (_ssl.c:2263)'")

The error message appear in both passed and failed tests.

Due to the randomness in its occurrence, initial suspected causes is neo4j is being killed due to OOM.

[ylei-tsubame]

At this point, many of the tests do not complete due to pieces of the system being outdated. It is recommended to revisit the CI solution.

Some known requirements that are not documented:

1. IPMI-related tests requires setting up a VM named test-ipmi (although this name can be changed in behave.ini). When the tests setup the IPMI simulation, it uses the defaults hard coded in system_modeler.py. Note that vmport is the port on the VM that is responsible for accepting incoming requests, i.e., ipmitool queries; it is set when configuring the BMC QEMU device; see where 9102 appears in the doc's BMC server section).
2. It is a requirement to install libvirt because the IPMI tests require a VM; this is not listed under the dev requirements.