add BarcodeType test

+import 'package:flutter_test/flutter_test.dart';
+import 'package:mobile_scanner/src/enums/barcode_type.dart';
+
+void main() {
+  group('$BarcodeType tests', () {
+    test('can be created from raw value', () {
+      const values = <int, BarcodeType>{
+        0: BarcodeType.unknown,
+        1: BarcodeType.contactInfo,
+        2: BarcodeType.email,
+        3: BarcodeType.isbn,
+        4: BarcodeType.phone,
+        5: BarcodeType.product,
+        6: BarcodeType.sms,
+        7: BarcodeType.text,
+        8: BarcodeType.url,
+        9: BarcodeType.wifi,
+        10: BarcodeType.geo,
+        11: BarcodeType.calendarEvent,
+        12: BarcodeType.driverLicense,
+      };
+
+      for (final MapEntry<int, BarcodeType> entry in values.entries) {
+        final BarcodeType result = BarcodeType.fromRawValue(entry.key);
+
+        expect(result, entry.value);
+      }
+    });
+
+    test('invalid raw value creates unknown barcode type', () {
+      final BarcodeType negative = BarcodeType.fromRawValue(-1);
+      final BarcodeType outOfRange = BarcodeType.fromRawValue(13);
+
+      expect(negative, BarcodeType.unknown);
+      expect(outOfRange, BarcodeType.unknown);
+    });
+
+    test('can be converted to raw value', () {
+      const values = <BarcodeType, int>{
+        BarcodeType.unknown: 0,
+        BarcodeType.contactInfo: 1,
+        BarcodeType.email: 2,
+        BarcodeType.isbn: 3,
+        BarcodeType.phone: 4,
+        BarcodeType.product: 5,
+        BarcodeType.sms: 6,
+        BarcodeType.text: 7,
+        BarcodeType.url: 8,
+        BarcodeType.wifi: 9,
+        BarcodeType.geo: 10,
+        BarcodeType.calendarEvent: 11,
+        BarcodeType.driverLicense: 12,
+      };
+
+      for (final MapEntry<BarcodeType, int> entry in values.entries) {
+        final int result = entry.key.rawValue;
+
+        expect(result, entry.value);
+      }
+    });
+  });
+}