The first and only thing in the MTConnect workstream that exercises the driver
against a real Agent; everything else runs on canned XML.
Fixture (Docker/): two services, both stock images with this folder bind-mounted.
- `agent` mtconnect/agent:2.7.0.12 on :5000. NOTE the repo name: the source
project is mtconnect/cppagent but the PUBLISHED image is
mtconnect/agent; mtconnect/cppagent does not exist on Docker Hub.
- `adapter` a stdlib SHDR feeder. Required, not optional: the agent image ships
only the binary + schemas/styles, so a lone Agent answers /probe and
then reports every observation UNAVAILABLE forever, which can prove
nothing about reads or streaming.
Devices.xml seeds one DataItem per inference branch (SAMPLE+units, TIME_SERIES,
PART_COUNT/LINE_NUMBER, controlled vocab, DATA_SET, CONDITION), gives every named
item `name != id` (the inverse of the hand-authored unit fixtures), and leaves one
EVENT permanently unfed so UNAVAILABLE -> BadNoCommunication has a live subject.
Suite (12 tests) asserts STRUCTURALLY against the Agent's own /probe response, never
by literal id, so it survives an edit to Devices.xml and can be pointed at a real
machine tool via MTCONNECT_AGENT_ENDPOINT. It skips cleanly (12/12) when no Agent
answers, and each test carries a hard [Fact(Timeout)] so a half-up fixture cannot
wedge a build.
Three findings from bringing the fixture up, each now pinned in a comment:
- agent.cfg must be pure ASCII; one non-ASCII byte in a COMMENT makes the config
parser reject the whole file with a bare "Failed / Stopped at line: N" and exit.
- `sampleCount` is an attribute of a TIME_SERIES observation, not of a DataItem
declaration. A real Agent meeting one on a declaration DROPS THE ENTIRE DATA ITEM
from the device model, so the inference only ever sees null and a live TIME_SERIES
tag is always variable-length. Asserted, not ignored.
- The Agent's own <Agent> self-model publishes update-rate SAMPLEs that tick whether
or not any adapter is attached. Excluding them is load-bearing: with them included
the "live stream delivered a changed value" test passed with the fixture's data
source deliberately stopped.
MTConnectError-under-HTTP-200 is NOT covered live and cannot be: cppagent 2.7 answers
an unknown device 404 and an out-of-range sequence 400, each with a well-formed error
body. That shape stays canned-only, and the suite says so.
Joseph Doherty
cf9ce91e51