qrloop/src/__tests__/errors.ts

Envelop big blob of data into frames that can be displayed in series of QR Codes

import {
  dataToFrames,
  parseFramesReducer,
  areFramesComplete,
  currentNumberOfFrames,
  totalNumberOfFrames,
  framesToData,
} from "..";

test("premature framesToData should throw", () => {
  expect(() => framesToData()).toThrow();
  expect(() => framesToData(null)).toThrow();

  const data = Buffer.from(
    Array(1000)
      .fill(null)
      .map((_, i) => i % 256)
  );
  const framesExport = dataToFrames(data, 200);
  expect(framesExport.length).toBeGreaterThan(2);
  const framesImport = parseFramesReducer(
    parseFramesReducer(null, framesExport[0]),
    framesExport[1]
  );

  expect(areFramesComplete(framesImport)).toBe(false);
  expect(currentNumberOfFrames(framesImport)).toBeLessThan(
    totalNumberOfFrames(framesImport) || -1
  );
  expect(() => framesToData(framesImport)).toThrow();
});

test("corrupted data through framesToData should throw", () => {
  const data = Buffer.from(
    Array(1000)
      .fill(null)
      .map((_, i) => i % 256)
  );
  const framesExport = dataToFrames(data, 200);
  const framesImport = framesExport.reduce(parseFramesReducer, null);

  if (!framesImport) throw new Error("falsy framesImport");

  framesImport.frames[1].data[10]++; // corrupt one bit of the second frame

  expect(() => framesToData(framesImport)).toThrow();
});

test("corrupted data can be recoverable", () => {
  const data = Buffer.from(
    Array(1000)
      .fill(null)
      .map((_, i) => i % 256)
  );
  const framesExport = dataToFrames(data, 200);

  const framesImport = framesExport.reduce(parseFramesReducer, null);
  if (!framesImport) throw new Error("falsy framesImport");

  framesImport.frames[1].data[10]++; // corrupt one bit of the second frame
  expect(() => framesToData(framesImport)).toThrow();

  const framesImport2 = framesExport.reduce(parseFramesReducer, framesImport);
  expect(framesToData(framesImport2)).toMatchObject(data);
});