blob: 170dba91c62231fb1a853097c0bc509390f464a5 [file] [log] [blame]
// Copyright (c) 2013, 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";
main() {
bool checkedMode = false;
assert((checkedMode = true));
void test(expectedList, generatedIterable) {
Expect.equals(expectedList.length, generatedIterable.length);
Expect.listEquals(expectedList, generatedIterable.toList());
test([], new Iterable.generate(0));
test([0], new Iterable.generate(1));
test([0,1,2,3,4], new Iterable.generate(5));
test(["0","1","2","3","4"], new Iterable.generate(5, (x) => "$x"));
test([2,3,4,5,6], new Iterable.generate(7).skip(2));
test([0,1,2,3,4], new Iterable.generate(7).take(5));
test([], new Iterable.generate(5).skip(6));
test([], new Iterable.generate(5).take(0));
test([], new Iterable.generate(5).take(3).skip(3));
test([], new Iterable.generate(5).skip(6).take(0));
// Test types.
Iterable<int> it = new Iterable<int>.generate(5);
Expect.isTrue(it is Iterable<int>);
Expect.isTrue(it.iterator is Iterator<int>);
Expect.isTrue(it is! Iterable<String>);
Expect.isTrue(it.iterator is! Iterator<String>);
test([0,1,2,3,4], it);
Iterable<String> st = new Iterable<String>.generate(5, (x) => "$x");
Expect.isTrue(st is Iterable<String>);
Expect.isTrue(st.iterator is Iterator<String>);
Expect.isFalse(st is Iterable<int>);
Expect.isFalse(st.iterator is Iterator<int>);
test(["0","1","2","3","4"], st);
if (checkedMode) {
Expect.throws(() => new Iterable<String>.generate(5));
// Omitted generator function means `(int x) => x`, and the type parameters
// must then be compatible with `int`.
// Check that we catch invalid type parameters.
// Valid types:
Iterable<int> iter1 = new Iterable<int>.generate(5);
Expect.equals(2, iter1.elementAt(2));
Iterable<num> iter2 = new Iterable<num>.generate(5);
Expect.equals(2, iter2.elementAt(2));
Iterable<Object> iter3 = new Iterable<Object>.generate(5);
Expect.equals(2, iter3.elementAt(2));
Iterable<dynamic> iter4 = new Iterable<dynamic>.generate(5);
Expect.equals(2, iter4.elementAt(2));
// Invalid types:
Expect.throws(() => new Iterable<String>.generate(5));
Expect.throws(() => new Iterable<Null>.generate(5));
Expect.throws(() => new Iterable<bool>.generate(5));
// Regression:
var count = 0;
var iter = new Iterable.generate(5, (v) { count++; return v; });
Expect.equals(0, count);
Expect.equals(2, iter.elementAt(2)); // Doesn't compute the earlier values.
Expect.equals(1, count);
Expect.equals(2, iter.skip(2).first); // Doesn't compute the skipped values.
Expect.equals(2, count);