Migrate test block 10 to Dart 2.0.

tests/corelib/iterable_fold_test.dart

-// Copyright (c) 2014, 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 "package:expect/expect.dart";
-import 'dart:collection';
-import 'dart:typed_data';
-
-class MyList extends ListBase {
-  List list;
-  MyList(this.list);
-
-  get length => list.length;
-  set length(val) {
-    list.length = val;
-  }
-
-  operator [](index) => list[index];
-  operator []=(index, val) => list[index] = val;
-}
-
-id(x) => x;
-
-main() {
-  for (var iterable in [
-    const [1, 2, 3],
-    [1, 2, 3],
-    new List(3)
-      ..[0] = 1
-      ..[1] = 2
-      ..[2] = 3,
-    {1: 1, 2: 2, 3: 3}.keys,
-    {1: 1, 2: 2, 3: 3}.values,
-    new Iterable.generate(3, (x) => x + 1),
-    new List.generate(3, (x) => x + 1),
-    [0, 1, 2, 3].where((x) => x > 0),
-    [0, 1, 2].map((x) => x + 1),
-    [
-      [1, 2],
-      [3]
-    ].expand(id),
-    [3, 2, 1].reversed,
-    [0, 1, 2, 3].skip(1),
-    [1, 2, 3, 4].take(3),
-    new Uint8List(3)
-      ..[0] = 1
-      ..[1] = 2
-      ..[2] = 3,
-    (new HashMap()
-          ..[1] = 1
-          ..[2] = 2
-          ..[3] = 3)
-        .keys,
-    (new HashMap()
-          ..[1] = 1
-          ..[2] = 2
-          ..[3] = 3)
-        .values,
-    (new SplayTreeMap()
-          ..[1] = 0
-          ..[2] = 0
-          ..[3] = 0)
-        .keys,
-    (new SplayTreeMap()
-          ..[0] = 1
-          ..[1] = 2
-          ..[2] = 3)
-        .values,
-    new HashSet()..add(1)..add(2)..add(3),
-    new LinkedHashSet()..add(1)..add(2)..add(3),
-    new SplayTreeSet()..add(1)..add(2)..add(3),
-    "\x01\x02\x03".codeUnits,
-    "\x01\x02\x03".runes,
-    new MyList([1, 2, 3]),
-  ]) {
-    int callCount = 0;
-    var result = iterable.fold(0, (x, y) {
-      callCount++;
-      return x + y;
-    });
-    Expect.equals(6, result, "${iterable.runtimeType}");
-    Expect.equals(3, callCount);
-  }
-
-  // Empty iterables are allowed.
-  for (var iterable in [
-    const [],
-    [],
-    new List(0),
-    {}.keys,
-    {}.values,
-    new Iterable.generate(0, (x) => x + 1),
-    new List.generate(0, (x) => x + 1),
-    [0, 1, 2, 3].where((x) => false),
-    [].map((x) => x + 1),
-    [[], []].expand(id),
-    [].reversed,
-    [0, 1, 2, 3].skip(4),
-    [1, 2, 3, 4].take(0),
-    new Uint8List(0),
-    (new HashMap()).keys,
-    (new HashMap()).values,
-    (new SplayTreeMap()).keys,
-    (new SplayTreeMap()).values,
-    new HashSet(),
-    new LinkedHashSet(),
-    new SplayTreeSet(),
-    "".codeUnits,
-    "".runes,
-    new MyList([]),
-  ]) {
-    Expect.equals(42, iterable.fold(42, (x, y) => throw "Unreachable"));
-  }
-
-  // Singleton iterables are calling reduce function.
-  for (var iterable in [
-    const [1],
-    [1],
-    new List(1)..[0] = 1,
-    {1: 1}.keys,
-    {1: 1}.values,
-    new Iterable.generate(1, (x) => x + 1),
-    new List.generate(1, (x) => x + 1),
-    [0, 1, 2, 3].where((x) => x == 1),
-    [0].map((x) => x + 1),
-    [
-      [],
-      [1]
-    ].expand(id),
-    [1].reversed,
-    [0, 1].skip(1),
-    [1, 2, 3, 4].take(1),
-    new Uint8List(1)..[0] = 1,
-    (new HashMap()..[1] = 0).keys,
-    (new HashMap()..[0] = 1).values,
-    (new SplayTreeMap()..[1] = 0).keys,
-    (new SplayTreeMap()..[0] = 1).values,
-    new HashSet()..add(1),
-    new LinkedHashSet()..add(1),
-    new SplayTreeSet()..add(1),
-    "\x01".codeUnits,
-    "\x01".runes,
-    new MyList([1]),
-  ]) {
-    Expect.equals(43, iterable.fold(42, (x, y) => x + y));
-  }
-
-  // Concurrent modifications not allowed.
-  testModification(base, modify, transform) {
-    var iterable = transform(base);
-    Expect.throws(() {
-      iterable.fold(0, (x, y) {
-        modify(base);
-        return x + y;
-      });
-    }, (e) => e is ConcurrentModificationError);
-  }
-
-  void add4(collection) {
-    collection.add(4);
-  }
-
-  void put4(map) {
-    map[4] = 4;
-  }
-
-  testModification([1, 2, 3], add4, id);
-  testModification(new HashSet()..add(1)..add(2)..add(3), add4, id);
-  testModification(new LinkedHashSet()..add(1)..add(2)..add(3), add4, id);
-  testModification(new SplayTreeSet()..add(1)..add(2)..add(3), add4, id);
-  testModification(new MyList([1, 2, 3]), add4, id);
-
-  testModification([0, 1, 2, 3], add4, (x) => x.where((x) => x > 0));
-  testModification([0, 1, 2], add4, (x) => x.map((x) => x + 1));
-  testModification([
-    [1, 2],
-    [3]
-  ], add4, (x) => x.expand((x) => x));
-  testModification([3, 2, 1], add4, (x) => x.reversed);
-  testModification({1: 1, 2: 2, 3: 3}, put4, (x) => x.keys);
-  testModification({1: 1, 2: 2, 3: 3}, put4, (x) => x.values);
-  var hashMap = new HashMap()
-    ..[1] = 1
-    ..[2] = 2
-    ..[3] = 3;
-  testModification(hashMap, put4, (x) => x.keys);
-  hashMap = new HashMap()
-    ..[1] = 1
-    ..[2] = 2
-    ..[3] = 3;
-  testModification(hashMap, put4, (x) => x.values);
-  var splayMap = new SplayTreeMap()
-    ..[1] = 1
-    ..[2] = 2
-    ..[3] = 3;
-  testModification(splayMap, put4, (x) => x.keys);
-  splayMap = new SplayTreeMap()
-    ..[1] = 1
-    ..[2] = 2
-    ..[3] = 3;
-  testModification(splayMap, put4, (x) => x.values);
-}