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packages/quiver/test/iterables/enumerate_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.enumerate_test;
+
+import 'package:test/test.dart';
+import 'package:quiver/iterables.dart';
+
+main() {
+  group('enumerate', () {
+    test("should add indices to its argument", () {
+      var e = enumerate(['a', 'b', 'c']);
+      expect(e.map((v) => v.index), [0, 1, 2]);
+      expect(e.map((v) => v.value), ['a', 'b', 'c']);
+    });
+
+    test("should return an empty iterable given an empty iterable", () {
+      expect(enumerate([]), []);
+    });
+
+    test("should add indices to its argument", () {
+      var e = enumerate(['a', 'b', 'c']);
+      expect(e.map((v) => v.index), [0, 1, 2]);
+      expect(e.map((v) => v.index), [ 0, 1, 2 ],
+          reason: 'should enumerate to the same values a second time');
+    });
+
+    test("first", () {
+      var e = enumerate(['a', 'b', 'c']);
+      expect(e.first.value, 'a');
+      expect(e.first.index, 0);
+      expect(e.first.value, 'a');
+    });
+
+    test("last", () {
+      var e = enumerate(['a', 'b', 'c']);
+      expect(e.last.value, 'c');
+      expect(e.last.index, 2);
+      expect(e.last.value, 'c');
+    });
+
+    test("single", () {
+      var e = enumerate(['a']);
+      expect(e.single.value, 'a');
+      expect(e.single.index, 0);
+      expect(e.single.value, 'a');
+
+      expect(() => enumerate([1, 2]).single, throws);
+    });
+
+    test("length", () {
+      expect(enumerate([7, 8, 9]).length, 3);
+    });
+
+    test("elementAt", () {
+      var list = ['a', 'b', 'c'];
+      var e = enumerate(list);
+      for (int i = 2; i >= 0; i--) {
+        expect(e.elementAt(i).value, list[i]);
+        expect(e.elementAt(i).index, i);
+      }
+    });
+
+    test("equals and hashcode", () {
+      var list = ['a', 'b', 'c'];
+      var e1 = enumerate(list);
+      var e2 = enumerate(list);
+      for (int i = 0; i < 2; i++) {
+        expect(e1.elementAt(i), e2.elementAt(i));
+        expect(e1.elementAt(i).hashCode, e1.elementAt(i).hashCode);
+        expect(identical(e1.elementAt(i), e2.elementAt(i)), isFalse);
+      }
+    });
+  });
+}