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packages/quiver/test/iterables/concat_test.dart

+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+library quiver.iterables.concat_test;
+
+import 'package:test/test.dart';
+import 'package:quiver/iterables.dart';
+
+main() {
+  group('concat', () {
+    test('should handle empty input iterables', () {
+      expect(concat([]), isEmpty);
+    });
+
+    test('should handle single input iterables', () {
+      expect(concat([[1, 2, 3]]), [1, 2, 3]);
+    });
+
+    test('should chain multiple input iterables', () {
+      expect(concat([[1, 2, 3], [-1, -2, -3]]), [1, 2, 3, -1, -2, -3]);
+    });
+
+    test('should throw for null input', () {
+      expect(() => concat(null), throws);
+    });
+
+    test('should throw if any input is null', () {
+      expect(() => concat([[1, 2], null, [3, 4]]).toList(), throws);
+    });
+
+    test('should reflectchanges in the inputs', () {
+      var a = [1, 2];
+      var b = [4, 5];
+      var ab = concat([a, b]);
+      expect(ab, [1, 2, 4, 5]);
+      a.add(3);
+      b.add(6);
+      expect(ab, [1, 2, 3, 4, 5, 6]);
+    });
+  });
+}