micarrsim/tests/unit/activity-monitor.test.js

import {
  analyzeCfarActivity,
  estimateCfarActivityWorkload,
} from "/packages/acoustics-core/activity-monitor.js";

function sinusoid(sampleCount, sampleRate, frequencyHz, amplitude = 1) {
  return Float64Array.from(
    { length: sampleCount },
    (_, index) =>
      amplitude * Math.sin((2 * Math.PI * frequencyHz * index) / sampleRate),
  );
}

function detectorOptions(overrides = {}) {
  return {
    samples: sinusoid(128, 6_400, 1_200),
    sampleRate: 6_400,
    fftSize: 64,
    hopSize: 64,
    window: "hann",
    channelId: "mic-reference",
    detector: "os-cfar",
    trainingCellsPerSide: 4,
    guardCellsPerSide: 1,
    rank: 6,
    nominalFalseAlarmProbability: 0.01,
    ...overrides,
  };
}

test("CFAR activity workload counts complete frames and every one-sided bin", () => {
  const workload = estimateCfarActivityWorkload({
    sampleCount: 160,
    fftSize: 64,
    hopSize: 32,
  });
  assertEqual(workload.frameCount, 4, "complete frame count");
  assertEqual(workload.binCount, 33, "one-sided bin count");
  assertEqual(workload.binDecisionCount, 132, "all frame/bin records");
  assertEqual(workload.fftButterflyCount, 768, "radix-2 butterfly count");
});

test("CFAR activity monitor preserves raw bins without time, microphone, or band fusion", async () => {
  const result = await analyzeCfarActivity(detectorOptions());
  assertEqual(result.kind, "micarrsim.cfar-activity-analysis/1", "result kind");
  assertEqual(result.channel.channelId, "mic-reference", "explicit channel");
  assertEqual(result.channel.microphoneFusion, "none", "no microphone fusion");
  assertEqual(result.frames.length, 2, "every complete frame retained");
  assertEqual(result.frames[0].bins.length, 33, "every one-sided bin retained");
  assertEqual(result.frames[0].bins[0].status, "untested", "DC remains untested");
  assertEqual(
    result.frames[0].bins[32].status,
    "untested",
    "Nyquist remains untested",
  );
  assertEqual(result.summary.selectionApplied, false, "no selection");
  assertEqual(result.summary.clusteringApplied, false, "no clustering");
  assertEqual(result.summary.localizationApplied, false, "no localization");
  assertEqual(
    result.detectorModel.processing.bandFusion,
    false,
    "no band fusion",
  );
  assert(
    result.frames.some((frame) => frame.bins[12].status === "detected"),
    "the exact 1.2 kHz ADC bin is reported as detected",
  );
});

test("above-Nyquist analog tone is reported only at its observable ADC alias", async () => {
  const sampleRate = 6_400;
  const analogFrequencyHz = 7_600;
  const result = await analyzeCfarActivity(detectorOptions({
    samples: sinusoid(128, sampleRate, analogFrequencyHz),
  }));
  assert(
    result.frames.some((frame) => frame.bins[12].status === "detected"),
    "7.6 kHz samples expose the 1.2 kHz ADC bin",
  );
  assertEqual(
    result.input.analogFrequencyOrAliasOrderInferred,
    false,
    "monitor does not infer analog alias order",
  );
  assertEqual(result.input.sceneTruthUsed, false, "Scene truth is not an input");
  assertEqual(
    Object.prototype.hasOwnProperty.call(result.input, "analogFrequencyHz"),
    false,
    "the result does not invent an analog carrier field",
  );
  assertEqual(
    Object.prototype.hasOwnProperty.call(result.frames[0].bins[12], "analogFrequencyHz"),
    false,
    "the detected ADC bin contains no hidden analog carrier",
  );
});

test("CA and OS activity analyses stay separate algorithms", async () => {
  const ca = await analyzeCfarActivity(detectorOptions({
    detector: "ca-cfar",
    rank: undefined,
  }));
  const os = await analyzeCfarActivity(detectorOptions());
  assertEqual(ca.detectorModel.detector, "ca-cfar", "CA identity");
  assertEqual(os.detectorModel.detector, "os-cfar", "OS identity");
  assertEqual(
    ca.detectorModel.processing.detectorFusion,
    false,
    "CA has no detector fusion",
  );
  assertEqual(
    os.detectorModel.processing.detectorFusion,
    false,
    "OS has no detector fusion",
  );
});

test("CFAR activity monitor is deterministic and preserves raw powers", async () => {
  const first = await analyzeCfarActivity(detectorOptions());
  const second = await analyzeCfarActivity(detectorOptions());
  for (let frameIndex = 0; frameIndex < first.frames.length; frameIndex += 1) {
    for (let bin = 0; bin < first.frames[frameIndex].bins.length; bin += 1) {
      const left = first.frames[frameIndex].bins[bin];
      const right = second.frames[frameIndex].bins[bin];
      assertEqual(left.status, right.status, "deterministic status");
      assertEqual(left.cutPower, right.cutPower, "deterministic raw CUT power");
      assertEqual(
        left.referencePower,
        right.referencePower,
        "deterministic reference power",
      );
      assertEqual(
        left.thresholdPower,
        right.thresholdPower,
        "deterministic threshold",
      );
    }
  }
});

test("CFAR activity monitor rejects implicit channel fusion and hard-cap overflow", async () => {
  let channelError = null;
  try {
    await analyzeCfarActivity(detectorOptions({
      samples: [
        sinusoid(64, 6_400, 1_200),
        sinusoid(64, 6_400, 1_200),
      ],
    }));
  } catch (error) {
    channelError = error;
  }
  assert(channelError instanceof Error, "nested channel input is rejected");

  let capError = null;
  try {
    await analyzeCfarActivity(detectorOptions({
      maximumBinDecisionCount: 65,
    }));
  } catch (error) {
    capError = error;
  }
  assert(
    capError?.message.includes("maximumBinDecisionCount"),
    "bin decision cap rejects work instead of truncating results",
  );
});

test("CFAR activity monitor honors an already-aborted signal", async () => {
  const controller = new AbortController();
  controller.abort();
  let abortError = null;
  try {
    await analyzeCfarActivity(detectorOptions({ signal: controller.signal }));
  } catch (error) {
    abortError = error;
  }
  assertEqual(abortError?.name, "AbortError", "typed abort");
});