Add min and max to Iterable and Stream.

tests/corelib/iterable_min_max_test.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#import "dart:collection";
+
+class C {
+  final x;
+  const C(this.x);
+  int get hashCode => x.hashCode;
+  bool operator==(var other) => other is C && x == other.x;
+}
+
+var inf = Double.INFINITY;
+
+var intList = const [0,1,-1,-5,5,-1000,1000,-7,7];
+var doubleList = const [-0.0, 0.0, -1.0, 1.0, -1000.0, 1000.0, -inf, inf];
+var stringList = const ["bbb", "bba", "bab", "abb", "bbc", "bcb", "cbb", "bb"];
+var cList = const [const C(5), const C(3), const C(8),
+                   const C(0), const C(10), const C(6)];
+int compareC(C a, C b) => a.x.compare(b.x);
+
+
+testMinMax(iterable, min, max) {
+  Expect.equals(min, iterable.min());
+  Expect.equals(min, iterable.min(Comparable.compare));
+  Expect.equals(min, Collections.min(iterable));
+  Expect.equals(min, Collections.min(iterable, Comparable.compare));
+  Expect.equals(max, iterable.min((a, b) => Comparable.compare(b, a)));
+
+  Expect.equals(max, iterable.max());
+  Expect.equals(max, iterable.max(Comparable.compare));
+  Expect.equals(max, Collections.max(iterable));
+  Expect.equals(max, Collections.max(iterable, Comparable.compare));
+  Expect.equals(min, iterable.max((a, b) => Comparable.compare(b, a)));
+}
+
+
+main() {
+  testMinMax(const [], null, null);
+  testMinMax([], null, null);
+
+  testMinMax(intList, -1000, 1000);  // Const list.
+  testMinMax(new List.from(intList), -1000, 1000);  // Non-const list.
+  testMinMax(new Set.from(intList), -1000, 1000);  // Set.
+
+  testMinMax(doubleList, -inf, inf);
+  testMinMax(new List.from(doubleList), -inf, inf);
+  testMinMax(new Set.from(doubleList), -inf, inf);
+
+  testMinMax(stringList, "abb", "cbb");
+  testMinMax(new List.from(stringList), "abb", "cbb");
+  testMinMax(new Set.from(stringList), "abb", "cbb");
+
+  // Objects that are not Comparable.
+  Expect.equals(const C(0), cList.min(compareC));
+  Expect.equals(const C(0), Collections.min(cList, compareC));
+  Expect.equals(const C(0), new List.from(cList).min(compareC));
+  Expect.equals(const C(0), Collections.min(new List.from(cList), compareC));
+  Expect.equals(const C(0), new Set.from(cList).min(compareC));
+  Expect.equals(const C(0), Collections.min(new Set.from(cList), compareC));
+
+  Expect.equals(const C(10), cList.max(compareC));
+  Expect.equals(const C(10), Collections.max(cList, compareC));
+  Expect.equals(const C(10), new List.from(cList).max(compareC));
+  Expect.equals(const C(10), Collections.max(new List.from(cList), compareC));
+  Expect.equals(const C(10), new Set.from(cList).max(compareC));
+  Expect.equals(const C(10), Collections.max(new Set.from(cList), compareC));
+
+  Expect.throws(cList.min, (e) => e is NoSuchMethodError);
+  Expect.throws(cList.max, (e) => e is NoSuchMethodError);
+}
+