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packages/quiver/test/iterables/partition_test.dart

+// Copyright 2014 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.partition_test;
+
+import 'package:test/test.dart';
+import 'package:quiver/iterables.dart';
+
+main() {
+  group('partition', () {
+    test('should throw when size is <= 0', () {
+      expect(() => partition([1, 2, 3], 0), throwsArgumentError);
+      expect(() => partition([1, 2, 3], -1), throwsArgumentError);
+    });
+
+    test('should return an empty list for empty input iterable', () {
+      expect(partition([], 5), equals([]));
+    });
+
+    test('should return one partition if partition size < input size', () {
+      var it = partition([1, 2, 3], 5).iterator;
+      expect(it.moveNext(), isTrue);
+      expect(it.current, equals([1, 2, 3]));
+      expect(it.moveNext(), isFalse);
+      expect(it.current, isNull);
+    });
+
+    test('should return one partition if partition size == input size', () {
+      var it = partition([1, 2, 3, 4, 5], 5).iterator;
+      expect(it.moveNext(), isTrue);
+      expect(it.current, equals([1, 2, 3, 4, 5]));
+      expect(it.moveNext(), isFalse);
+      expect(it.current, isNull);
+    });
+
+    test('should return partitions of correct size if '
+        'partition size > input size', () {
+      var it = partition([1, 2, 3, 4, 5], 3).iterator;
+      expect(it.moveNext(), isTrue);
+      expect(it.current, equals([1, 2, 3]));
+      expect(it.moveNext(), isTrue);
+      expect(it.current, equals([4, 5]));
+      expect(it.moveNext(), isFalse);
+      expect(it.current, isNull);
+    });
+  });
+}