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Version: v0.1.11

Test your C-CDA handling with generated fixtures

In this tutorial we write a small piece of code that reads C-CDA R2.1 documents and test it with fixtures from @cosyte/synth. We start from one generated Continuity of Care Document (CCD) and end with a document that carries a deprecated code and the warning it should raise. Every document is synthetic, so the tests can live in a public repository and print their input to a CI log.

You need @cosyte/synth and @cosyte/ccda installed (Installation). Each step is a complete program you can run on its own.

1. Write the code under test​

The code under test reads a document with @cosyte/ccda and pulls out its type, the patient's family name, and how many problems and medications it lists. Feed it a generated CCD, serialized to the XML a sending system would hand you:

import { parseCcda, serializeCcda } from "@cosyte/ccda";
import { generateCcd } from "@cosyte/synth/ccda";

function summarizeDocument(xml: string) {
  const doc = parseCcda(xml);
  return {
    documentType: doc.documentType,
    family: doc.getPatient()?.name?.family,
    problems: doc.getProblems().length,
    medications: doc.getMedications().length,
  };
}

const xml = serializeCcda(generateCcd({ seed: 12345 }));
const summary = summarizeDocument(xml);

summary.documentType; // => "ccd"
summary.problems > 0; // => true
summary.medications > 0; // => true

generateCcd returns @cosyte/ccda's document model; serializeCcda gives the XML.

2. Check what the fixture carries​

A generated value is not a value you typed, so assert on its kind rather than its spelling. The family name comes from the shipped pool of invented names, and the document reads back with no warnings:

import { parseCcda, serializeCcda } from "@cosyte/ccda";
import { SYNTHETIC_FAMILY_NAMES } from "@cosyte/synth";
import { generateCcd } from "@cosyte/synth/ccda";

const doc = parseCcda(serializeCcda(generateCcd({ seed: 12345 })));

SYNTHETIC_FAMILY_NAMES.includes(doc.getPatient()?.name?.family ?? ""); // => true
doc.warnings.length; // => 0

3. Run both document types through it​

ccdaCorpus alternates a CCD and a Referral Note. With a count of 2 you get one of each, and each artifact's kind says which. The code under test should report the same type the generator was asked for:

import { parseCcda } from "@cosyte/ccda";
import { ccdaCorpus } from "@cosyte/synth/ccda";

const corpus = ccdaCorpus({ seed: 42, count: 2 });
const types = corpus.artifacts.map((artifact) => parseCcda(artifact.content).documentType);

corpus.artifacts.map((artifact) => artifact.kind); // => ["ccd", "referralNote"]
types; // => ["ccd", "referralNote"]

4. Pin the seed​

A test that regenerates its fixture from a seed needs no fixture file, and its input does not change between runs, because the same seed gives the same bytes:

import { serializeCcda } from "@cosyte/ccda";
import { generateCcd } from "@cosyte/synth/ccda";

const first = serializeCcda(generateCcd({ seed: 12345 }));
const again = serializeCcda(generateCcd({ seed: 12345 }));

first === again; // => true

The bytes come from @cosyte/ccda's serializer, so pin the versions of @cosyte/synth and @cosyte/ccda in your lockfile as well as the seed.

5. Add a deprecated code​

Documents from older systems carry codes that have since been retired. generateCcdaQuirk puts a deprecated LOINC code in an otherwise clean document, and checks before it returns that @cosyte/ccda raises exactly the warning the quirk is meant to cause. Your code should still read the document, and the parser should flag the code:

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

const fixture = generateCcdaQuirk({ seed: 12345, quirk: "deprecated-loinc" });
const doc = parseCcda(fixture.content);

fixture.intendedWarnings; // => ["DEPRECATED_LOINC"]
doc.warnings.map((w) => w.code); // => ["DEPRECATED_LOINC"]
doc.documentType; // => "ccd"

What you built​

A reader for C-CDA documents, tested against a CCD and a Referral Note regenerated from a seed, plus a document with a known deviation and the warning it raises. None of it holds patient data.

Where to go next​