Measurement-output test vectors (contract §5.5)
vectors.json pins what a connector in measurement output publishes for given readings: the
measurement messages, their grouping and splits, the units metadata, and which readings still
publish a sample. The Rust SDK (impl/rust/crates/sdk/src/measure.rs) and the C SDK
(impl/c/sdk/src/measure.c, run by impl/c/tests/measure.c) both run every case in their unit
tests. The file is how the two implementations are kept identical below the end-to-end suites.
Each case has these fields:
| Field | Meaning |
|---|---|
name | What the case shows. |
config | A complete connector configuration (TOML), loaded by the build’s own loader. Its [connector] sets output = "measurements". |
generate | Optional. Points appended to the configuration: count points of datatype, with ids from the id pattern, where {i:04} is the point’s index with four digits. |
steps | Events in order. at is the device clock in milliseconds since the point tables were built. |
messages | The messages published, in order: topic, retain, and payload as JSON ("" for an empty, clearing payload). Compared as JSON, not as text. |
routing | One entry per read step: sample (the sample envelope is published) and measured (the reading also became a series, so the envelope carries "measured": true). |
split | Instead of messages and routing, for a case too large to list: the topic of every message and the number of series in each, in order. |
A step is one of the following:
| Step | Meaning |
|---|---|
{"at": t, "read": {...}} | A reading the report policy let through is offered. |
{"at": t, "read_all": {...}} | The same reading of every point of a device, in configuration order. |
{"at": t, "pass": true} | The end of a runtime pass: messages grouped by time are published. |
{"at": t, "due": true} | Frames whose window ended and samples that are due are published. The sample time is 2026-01-01T00:00:00.000Z plus at. |
{"at": t, "stale": {"device": d, "stale": b}} | The device’s link went down (true) or came back (false). |
A reading has a device, a point, a value (a number, a boolean or a string), a ts (RFC 3339
with milliseconds) and an optional quality ("good" by default, "bad" or "stale"). The
runner builds the sample as the module would return it for the configured point: a raw point
carries no value.
Numbers in a payload are written as an integer when they have no fraction and are below 1e15,
and otherwise in the shortest form that reads back as the same double, laid out as Rust’s ryu
prints it (1e20, 1.5e-7, 0.0001). Both builds format them alike, so their size estimates and
split points agree.
The split case checks the size budget: 2,000 series of about 65 bytes each split into messages
of 191 series, the most that keeps the thin-edge size plus 12 bytes per series under 15,000 bytes.