Read an ADS-B vertical rate from one shared field reader

src/sources/adsbFields.test.mjs

@@ -0,0 +1,33 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { readAdsbVerticalRateFpm } from './adsbFields.js';
+
+test('the barometric rate wins, a barometric 0 included', () => {
+  assert.equal(
+    readAdsbVerticalRateFpm({ baro_rate: -640, geom_rate: -832 }),
+    -640,
+  );
+  assert.equal(readAdsbVerticalRateFpm({ baro_rate: 0, geom_rate: 600 }), 0);
+});
+
+test('a GNSS rate stands in when no barometric rate is usable', () => {
+  for (const baro_rate of [
+    undefined,
+    null,
+    Number.NaN,
+    Infinity,
+    '300',
+    false,
+  ]) {
+    assert.equal(readAdsbVerticalRateFpm({ baro_rate, geom_rate: -832 }), -832);
+  }
+});
+
+test('no usable rate reads as null', () => {
+  assert.equal(readAdsbVerticalRateFpm({}), null);
+  assert.equal(readAdsbVerticalRateFpm(null), null);
+  assert.equal(
+    readAdsbVerticalRateFpm({ baro_rate: '300', geom_rate: true }),
+    null,
+  );
+});