Wrote unit tests for testing parsing location from EXIF

test/utils/parsing_loc_from_exif_test.dart

@@ -0,0 +1,121 @@
+import "package:photos/services/location_service.dart";
+import "package:test/test.dart";
+
+void main() {
+  group('toLocationObj', () {
+    test('returns null if lat or long are null', () {
+      final gpsData = GPSData(null, null, null, null);
+      expect(gpsData.toLocationObj(), isNull);
+
+      final gpsDataWithLatOnly = GPSData(null, [1, 2, 3], null, null);
+      expect(gpsDataWithLatOnly.toLocationObj(), isNull);
+
+      final gpsDataWithLongOnly = GPSData(null, null, null, [1, 2, 3]);
+      expect(gpsDataWithLongOnly.toLocationObj(), isNull);
+    });
+
+    test('returns null if lat or long have less than 3 elements', () {
+      final gpsData1 = GPSData(null, [1, 2], null, [1, 2, 3]);
+      expect(gpsData1.toLocationObj(), isNull);
+
+      final gpsData2 = GPSData(null, [1, 2, 3], null, [1, 2]);
+      expect(gpsData2.toLocationObj(), isNull);
+
+      final gpsData3 = GPSData(null, [1, 2], null, [1, 2]);
+      expect(gpsData3.toLocationObj(), isNull);
+    });
+
+    test('returns null if latRef or longRef is of invalid format', () {
+      final gpsData1 = GPSData("A", [1, 2, 3], "xyz", [1, 2, 3]);
+      expect(gpsData1.toLocationObj(), isNull);
+    });
+
+    void testParsingLocation(
+      String? latRef,
+      List<double> lat,
+      String? longRef,
+      List<double> long,
+      double expectedLat,
+      double expectedLong,
+    ) {
+      final gpsData = GPSData(latRef, lat, longRef, long);
+      final location = gpsData.toLocationObj();
+      expect(location, isNotNull);
+      expect(location!.latitude, closeTo(expectedLat, 0.00001));
+      expect(location.longitude, closeTo(expectedLong, 0.00001));
+    }
+
+    test('converts coordinates with different latRef and longRef combinations',
+        () {
+      testParsingLocation(
+        "N",
+        [40, 26, 46.84],
+        "E",
+        [79, 58, 56.33],
+        40.446344,
+        79.982313,
+      );
+      testParsingLocation(
+        "N",
+        [40, 26, 46.84],
+        "W",
+        [79, 58, 56.33],
+        40.446344,
+        -79.982313,
+      );
+      testParsingLocation(
+        "S",
+        [40, 26, 46.84],
+        "E",
+        [79, 58, 56.33],
+        -40.446344,
+        79.982313,
+      );
+      testParsingLocation(
+        "S",
+        [40, 26, 46.84],
+        "W",
+        [79, 58, 56.33],
+        -40.446344,
+        -79.982313,
+      );
+    });
+
+    test(
+        'converts coordinates with missing latRef and longRef but with signed lat and long',
+        () {
+      testParsingLocation(
+        null,
+        [40, 26, 46.84],
+        null,
+        [79, 58, 56.33],
+        40.446344,
+        79.982313,
+      );
+      testParsingLocation(
+        null,
+        [-40, 26, 46.84],
+        null,
+        [79, 58, 56.33],
+        -40.446344,
+        79.982313,
+      );
+      testParsingLocation(
+        null,
+        [40, 26, 46.84],
+        null,
+        [-79, 58, 56.33],
+        40.446344,
+        -79.982313,
+      );
+      testParsingLocation(
+        null,
+        [40, -26, 46.84],
+        null,
+        [79, -58, 56.33],
+        -40.446344,
+        -79.982313,
+      );
+    });
+  });
+}