mirror of
https://github.com/dart-lang/sdk
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b101a7d002
Change-Id: Ib33169c3e0ffc870915c189404074a1dea472546 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/196548 Reviewed-by: Bob Nystrom <rnystrom@google.com> Commit-Queue: Leaf Petersen <leafp@google.com>
75 lines
2.7 KiB
Dart
75 lines
2.7 KiB
Dart
// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// @dart = 2.9
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import "package:expect/expect.dart";
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main() {
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void test(expectedList, generatedIterable) {
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Expect.equals(expectedList.length, generatedIterable.length);
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Expect.listEquals(expectedList, generatedIterable.toList());
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}
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test([], new Iterable.generate(0));
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test([0], new Iterable.generate(1));
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test([0, 1, 2, 3, 4], new Iterable.generate(5));
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test(["0", "1", "2", "3", "4"], new Iterable.generate(5, (x) => "$x"));
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test([2, 3, 4, 5, 6], new Iterable.generate(7).skip(2));
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test([0, 1, 2, 3, 4], new Iterable.generate(7).take(5));
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test([], new Iterable.generate(5).skip(6));
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test([], new Iterable.generate(5).take(0));
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test([], new Iterable.generate(5).take(3).skip(3));
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test([], new Iterable.generate(5).skip(6).take(0));
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// Test types.
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Iterable<int> it = new Iterable<int>.generate(5);
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Expect.isTrue(it is Iterable<int>);
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Expect.isTrue(it.iterator is Iterator<int>);
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Expect.isTrue(it is! Iterable<String>);
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Expect.isTrue(it.iterator is! Iterator<String>);
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test([0, 1, 2, 3, 4], it);
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Iterable<String> st = new Iterable<String>.generate(5, (x) => "$x");
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Expect.isTrue(st is Iterable<String>);
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Expect.isTrue(st.iterator is Iterator<String>);
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Expect.isFalse(st is Iterable<int>);
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Expect.isFalse(st.iterator is Iterator<int>);
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test(["0", "1", "2", "3", "4"], st);
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Expect.throws(() => new Iterable<String>.generate(5));
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// Omitted generator function means `(int x) => x`, and the type parameters
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// must then be compatible with `int`.
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// Check that we catch invalid type parameters.
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// Valid types:
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Iterable<int> iter1 = new Iterable<int>.generate(5);
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Expect.equals(2, iter1.elementAt(2));
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Iterable<num> iter2 = new Iterable<num>.generate(5);
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Expect.equals(2, iter2.elementAt(2));
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Iterable<Object> iter3 = new Iterable<Object>.generate(5);
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Expect.equals(2, iter3.elementAt(2));
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Iterable<dynamic> iter4 = new Iterable<dynamic>.generate(5);
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Expect.equals(2, iter4.elementAt(2));
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// Invalid types:
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Expect.throws(() => new Iterable<String>.generate(5));
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Expect.throws(() => new Iterable<Null>.generate(5).elementAt(2)); //# 01: ok
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Expect.throws(() => new Iterable<bool>.generate(5));
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// Regression: https://github.com/dart-lang/sdk/issues/26358
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var count = 0;
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var iter = new Iterable.generate(5, (v) {
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count++;
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return v;
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});
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Expect.equals(0, count);
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Expect.equals(2, iter.elementAt(2)); // Doesn't compute the earlier values.
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Expect.equals(1, count);
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Expect.equals(2, iter.skip(2).first); // Doesn't compute the skipped values.
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Expect.equals(2, count);
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}
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