test(types): add pair tests

packages/wyatt_type_utils/test/pair_test.dart

@@ -0,0 +1,39 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:test/test.dart';
+import 'package:wyatt_type_utils/wyatt_type_utils.dart';
+
+void main() {
+  group('Pair<L,R>', () {
+    test('left returns correct value', () {
+      const Pair<int, bool> myPair = Pair(42, false);
+      expect(myPair.left, 42);
+    });
+    test('right returns correct value', () {
+      const Pair<int, bool> myPair = Pair(42, false);
+      expect(myPair.right, false);
+    });
+    test('toString() returns correct value', () {
+      const Pair<int, bool> myPair = Pair(42, false);
+      expect(myPair.toString(), '(42, false)');
+    });
+    test('toList() returns correct values', () {
+      const Pair<int, int> myPair = Pair(42, 10);
+      expect(myPair.toList(), [42, 10]);
+    });
+  });
+}