add AddressType test

+import 'package:flutter_test/flutter_test.dart';
+import 'package:mobile_scanner/src/enums/address_type.dart';
+
+void main() {
+  group('$AddressType tests', () {
+    test('can be created from raw value', () {
+      const values = <int, AddressType>{
+        0: AddressType.unknown,
+        1: AddressType.work,
+        2: AddressType.home,
+      };
+
+      for (final MapEntry<int, AddressType> entry in values.entries) {
+        final AddressType result = AddressType.fromRawValue(entry.key);
+
+        expect(result, entry.value);
+      }
+    });
+
+    test('invalid raw value creates unknown address type', () {
+      final AddressType negative = AddressType.fromRawValue(-1);
+      final AddressType outOfRange = AddressType.fromRawValue(3);
+
+      expect(negative, AddressType.unknown);
+      expect(outOfRange, AddressType.unknown);
+    });
+
+    test('can be converted to raw value', () {
+      const values = <AddressType, int>{
+        AddressType.unknown: 0,
+        AddressType.work: 1,
+        AddressType.home: 2,
+      };
+
+      for (final MapEntry<AddressType, int> entry in values.entries) {
+        final int result = entry.key.rawValue;
+
+        expect(result, entry.value);
+      }
+    });
+  });
+}