feat: Add serial compass support #0

test/widgets/compass_math_test.dart

@@ -0,0 +1,36 @@
+import 'dart:math';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:meshcore_sar_app/widgets/map/compass/compass_math.dart';
+
+void main() {
+  group('compass dial math', () {
+    test('rotates the rose opposite the heading', () {
+      expect(compassRoseRotationRadians(0), closeTo(0, 1e-10));
+      expect(compassRoseRotationRadians(90), closeTo(-pi / 2, 1e-10));
+      expect(compassRoseRotationRadians(450), closeTo(-pi / 2, 1e-10));
+    });
+
+    test('places east at the top when heading east', () {
+      expect(
+        compassDialAngleRadians(markerDegrees: 90, headingDegrees: 90),
+        closeTo(-pi / 2, 1e-10),
+      );
+      expect(
+        compassDialAngleRadians(markerDegrees: 270, headingDegrees: 90),
+        closeTo(pi / 2, 1e-10),
+      );
+    });
+
+    test('places west at the top when heading west', () {
+      expect(
+        compassDialAngleRadians(markerDegrees: 270, headingDegrees: 270),
+        closeTo(-pi / 2, 1e-10),
+      );
+      expect(
+        compassDialAngleRadians(markerDegrees: 90, headingDegrees: 270),
+        closeTo(pi / 2, 1e-10),
+      );
+    });
+  });
+}