Skip to main content
Version: v0.1.8

Generate vendor-quirk fixtures

A spec-clean fixture shows that a parser reads a correct message. A quirk fixture shows how it handles the deviations real vendor traffic carries: does it read the message, and does it raise the right warning?

Each quirk changes the structure of a message that otherwise reads back with no warnings, so that a parse with no profile raises exactly one intended warning code. The quirks are the ones the Cosyte parsers' own profile systems (defineProfile in @cosyte/hl7, defineCcdaProfile in @cosyte/ccda, defineAstmProfile in @cosyte/astm) describe as tolerable. Where a built-in public profile claims the deviation, the round trip also parses under that profile and reports whether it was suppressed or re-badged to PROFILE_QUIRK_APPLIED. Every quirk generator checks the intended warning before it returns, so it never hands you a fixture that does not raise it.

A quirk changes the shape of a message, never where its values come from, so a quirk fixture is as synthetic as any other. Quirks ship for HL7 v2, C-CDA, and ASTM; the quirk catalog lists every one.

HL7 v2: a vendor Z segment​

A site-defined Z segment is the usual HL7 v2 quirk. A parse with no profile flags it UNKNOWN_SEGMENT; a profile that declares the segment suppresses it. Here that is @cosyte/hl7's public visage imaging profile, which declares ZDS:

import { generateHl7Quirk, hl7QuirkRoundTrip } from "@cosyte/synth/hl7";

const rt = hl7QuirkRoundTrip(generateHl7Quirk({ seed: 12345, quirk: "unknown-zsegment" }));
rt.warnings; // => ["UNKNOWN_SEGMENT"]
rt.intendedWarningHeld; // => true
rt.withProfile?.tolerated; // => true

C-CDA: a deprecated LOINC code​

C-CDA profiles re-badge a tolerated deviation to PROFILE_QUIRK_APPLIED. A deprecated result LOINC code raises DEPRECATED_LOINC, and @cosyte/ccda's public smartScorecard profile re-badges it:

import { generateCcdaQuirk, ccdaQuirkRoundTrip } from "@cosyte/synth/ccda";

const rt = ccdaQuirkRoundTrip(generateCcdaQuirk({ seed: 12345, quirk: "deprecated-loinc" }));
rt.warnings; // => ["DEPRECATED_LOINC"]
rt.withProfile?.warnings; // => ["PROFILE_QUIRK_APPLIED"]
rt.withProfile?.tolerated; // => true

ASTM: a non-standard escape​

An ASTM &Z& escape raises ASTM_UNKNOWN_ESCAPE_SEQUENCE, and @cosyte/astm's public referenceCorpus profile, grounded in the open-source python-astm and SENAITE corpora, re-badges it:

import { generateAstmQuirk, astmQuirkRoundTrip } from "@cosyte/synth/astm";

const rt = astmQuirkRoundTrip(generateAstmQuirk({ seed: 12345, quirk: "unknown-escape" }));
rt.warnings; // => ["ASTM_UNKNOWN_ESCAPE_SEQUENCE"]
rt.withProfile?.tolerated; // => true

An unknown quirk name throws​

A quirk name outside the format's registry throws SYNTH_UNSUPPORTED_QUIRK. It is never ignored, and no fixture is made up for it:

import { generateHl7Quirk } from "@cosyte/synth/hl7";

let code = "";
try {
  generateHl7Quirk({ seed: 1, quirk: "no-such-quirk" as never });
} catch (err) {
  code = (err as { code?: string }).code ?? "";
}
code; // => "SYNTH_UNSUPPORTED_QUIRK"

Branch on err.code, never on err.message. The message is a fixed entry in the frozen SYNTH_FATAL_MESSAGES table and does not name the quirk you asked for: SynthError takes a code and no value, so nothing you pass reaches the thrown object. To see what a format accepts, read its registry directly: Object.keys(HL7_QUIRKS), Object.keys(CCDA_QUIRKS), Object.keys(ASTM_QUIRKS).

Build a quirk corpus​

Each format has a quirk corpus that cycles through every quirk in its registry. Its manifest lists the quirks applied, and each artifact's warnings holds the intended codes:

import { ccdaQuirkCorpus } from "@cosyte/synth/ccda";

const corpus = ccdaQuirkCorpus({ seed: 42 });
[...corpus.manifest.quirks].sort(); // => ["deprecated-code-system", "deprecated-loinc", "template-extension-absent"]

Choose the quirks with a profile​

defineSynthProfile names a set of quirks once, and a quirk corpus takes it as profile. Each format also exports a profile with every quirk it ships (hl7QuirkProfile, ccdaQuirkProfile, astmQuirkProfile):

import { defineSynthProfile } from "@cosyte/synth";
import { hl7QuirkCorpus } from "@cosyte/synth/hl7";

const labFeed = defineSynthProfile({ name: "lab-feed", quirks: ["unknown-escape"] });
const corpus = hl7QuirkCorpus({ seed: 1, count: 2, profile: labFeed });

corpus.manifest.quirks; // => ["unknown-escape"]
corpus.artifacts.map((a) => a.warnings); // => [["UNKNOWN_ESCAPE_SEQUENCE"], ["UNKNOWN_ESCAPE_SEQUENCE"]]

A profile that names a quirk outside the format's registry throws SYNTH_UNSUPPORTED_QUIRK. defineSynthProfile also accepts givenNames and familyNames and stores them on the profile, but no generator reads them in this release.

Where each quirk comes from​

Every quirk is grounded in a deviation that is documented in public, or in a parser's public profile: a published implementation guide, a vendor interface specification, or an open-source corpus that may be redistributed. A quirk that would need a private, vendor-attributed corpus is not shipped. Quirks for FHIR, X12, and NCPDP are not generated yet.