Migrated test block 168 to Dart 2.0.

tests/lib/async/future_foreach_test.dart

-// Copyright (c) 2017, 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.
-
-library future_foreach_test;
-
-import 'package:async_helper/async_helper.dart';
-import "package:expect/expect.dart";
-import 'dart:async';
-
-main() {
-  asyncStart();
-
-  testForeach(<int>[]);
-  testForeach(<int>[0]);
-  testForeach(<int>[0, 1, 2, 3]);
-
-  testForeachIterableThrows(
-      new Iterable<int>.generate(5, (i) => i < 4 ? i : throw "ERROR"),
-      4,
-      "ERROR");
-
-  testForeachFunctionThrows(new Iterable<int>.generate(5, (x) => x), 4);
-
-  asyncEnd();
-}
-
-void testForeach(Iterable<int> elements) {
-  for (var delay in [0, 1, 2]) {
-    asyncStart();
-    int length = elements.length;
-    int count = 0;
-    int nesting = 0;
-    Future.forEach<int>(elements, (int value) {
-      Expect.isTrue(nesting == 0, "overlapping calls detected");
-      if (delay == 0) return "something-$delay";
-      nesting++;
-      var future;
-      if (delay == 1) {
-        future = new Future(() => null);
-      } else {
-        future = new Future.microtask(() => null);
-      }
-      return future.then<String>((_) {
-        Expect.equals(1, nesting);
-        nesting--;
-        return "something-$delay";
-      });
-    }).then((_) {
-      asyncEnd();
-    }).catchError((e) {
-      Expect.fail("Throws: $e");
-    });
-  }
-}
-
-void testForeachIterableThrows(Iterable<int> elements, n, error) {
-  for (var delay in [0, 1, 2]) {
-    asyncStart();
-    int count = 0;
-    Future.forEach<int>(elements, (_) {
-      count++;
-      Expect.isTrue(n >= 0);
-      switch (delay) {
-        case 1:
-          return new Future<String>(() {});
-        case 2:
-          return new Future<String>.microtask(() {});
-      }
-    }).then((_) {
-      Expect.fail("Did not throw");
-    }, onError: (e) {
-      Expect.equals(n, count);
-      Expect.equals(error, e);
-      asyncEnd();
-    });
-  }
-}
-
-void testForeachFunctionThrows(Iterable<int> elements, n) {
-  for (var delay in [0, 1, 2]) {
-    asyncStart();
-    Future.forEach<int>(elements, (v) {
-      if (v == n) {
-        switch (delay) {
-          case 0:
-            throw "ERROR";
-          case 1:
-            return new Future<String>(() {
-              throw "ERROR";
-            });
-          case 2:
-            return new Future<String>.microtask(() {
-              throw "ERROR";
-            });
-        }
-      }
-      switch (delay) {
-        case 1:
-          return new Future(() {});
-        case 2:
-          return new Future.microtask(() {});
-      }
-    }).then((_) {
-      Expect.fail("Did not throw");
-    }, onError: (e) {
-      Expect.equals("ERROR", e);
-      asyncEnd();
-    });
-  }
-}