1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
package scala.collection
import org.junit.Assert._
import org.junit.Test
import org.junit.runner.RunWith
import org.junit.runners.JUnit4
import scala.tools.testing.AssertUtil._
import Seq.empty
@RunWith(classOf[JUnit4])
class IteratorTest {
@Test def groupedIteratorShouldNotAskForUnneededElement(): Unit = {
var counter = 0
val it = new Iterator[Int] { var i = 0 ; def hasNext = { counter = i; true } ; def next = { i += 1; i } }
val slidingIt = it sliding 2
slidingIt.next
assertEquals("Counter should be one, that means we didn't look further than needed", 1, counter)
}
@Test def groupedIteratorIsLazyWhenPadded(): Unit = {
var counter = 0
def it = new Iterator[Int] { var i = 0 ; def hasNext = { counter = i; true } ; def next = { i += 1; i } }
val slidingIt = it sliding 2 withPadding -1
slidingIt.next
assertEquals("Counter should be one, that means we didn't look further than needed", 1, counter)
}
@Test def dropDoesNotGrowStack(): Unit = {
def it = new Iterator[Throwable] { def hasNext = true ; def next = new Throwable }
assertEquals(it.drop(1).next.getStackTrace.length, it.drop(1).drop(1).next.getStackTrace.length)
}
@Test def dropIsChainable(): Unit = {
assertSameElements(1 to 4, Iterator from 0 take 5 drop 1)
assertSameElements(3 to 4, Iterator from 0 take 5 drop 3)
assertSameElements(empty, Iterator from 0 take 5 drop 5)
assertSameElements(empty, Iterator from 0 take 5 drop 10)
assertSameElements(0 to 4, Iterator from 0 take 5 drop 0)
assertSameElements(0 to 4, Iterator from 0 take 5 drop -1)
assertSameElements(2 to 8 by 2, Iterator from 0 take 5 drop 1 map (2 * _))
assertSameElements(2 to 8 by 2, Iterator from 0 take 5 map (2 * _) drop 1)
assertSameElements(3 to 4, Iterator from 0 take 5 drop 1 drop 2)
assertSameElements(3 to 4, Iterator from 0 take 5 drop 2 drop 1)
}
@Test def sliceIsChainable(): Unit = {
assertSameElements(3 to 6, Iterator from 0 slice (3, 7))
assertSameElements(empty, Iterator from 0 slice (3, 3))
assertSameElements(0 to 2, Iterator from 0 slice (-1, 3))
assertSameElements(empty, Iterator from 0 slice (3, -1))
assertSameElements(6 to 12 by 2, Iterator from 0 slice (3, 7) map (2 * _))
assertSameElements(6 to 12 by 2, Iterator from 0 map (2 * _) slice (3, 7))
assertSameElements(4 to 6, Iterator from 0 slice (3, 7) drop 1)
assertSameElements(4 to 7, Iterator from 0 drop 1 slice (3, 7))
assertSameElements(4 to 5, Iterator from 0 slice (3, 7) slice (1, 3))
assertSameElements(4 to 6, Iterator from 0 slice (3, 7) slice (1, 10))
}
// test/files/run/iterator-concat.scala
@Test def concatIsStackFriendly(): Unit = {
// Create `size` Function0s, each of which evaluates to an Iterator
// which produces 1. Then fold them over ++ to get a single iterator,
// which should sum to "size".
def mk(size: Int): Iterator[Int] = {
//val closures = (1 to size).toList.map(x => (() => Iterator(1)))
//closures.foldLeft(Iterator.empty: Iterator[Int])((res, f) => res ++ f())
List.fill(size)(() => Iterator(1)).foldLeft(Iterator.empty: Iterator[Int])((res, f) => res ++ f())
}
assertEquals(100, mk(100).sum)
assertEquals(1000, mk(1000).sum)
assertEquals(10000, mk(10000).sum)
assertEquals(100000, mk(100000).sum)
}
@Test def from(): Unit = {
val it1 = Iterator.from(-1)
val it2 = Iterator.from(0, -1)
assertEquals(-1, it1.next())
assertEquals(0, it2.next())
}
@Test def range(): Unit = {
assertEquals(5, Iterator.range(0, 10, 2).size)
assertEquals(0, Iterator.range(0, 10, -2).size)
assertEquals(5, Iterator.range(10, 0, -2).size)
assertEquals(0, Iterator.range(10, 0, 2).size)
assertEquals(1, Iterator.range(0, 10, 11).size)
assertEquals(10, Iterator.range(0, 10, 1).size)
assertEquals(10, Iterator.range(10, 0, -1).size)
}
@Test def range3(): Unit = {
val r1 = Iterator.range(0, 10)
assertTrue(r1 contains 5)
assertTrue(r1 contains 6)
assertFalse(r1 contains 4)
val r2a = Iterator.range(0, 10, 2)
assertFalse(r2a contains 5)
val r2b = Iterator.range(0, 10, 2)
assertTrue(r2b contains 6)
val r3 = Iterator.range(0, 10, 11)
assertFalse(r3 contains 5)
assertTrue(r3.isEmpty)
}
@Test def take(): Unit = {
assertEquals(10, (Iterator from 0 take 10).size)
}
@Test def foreach(): Unit = {
val it1 = Iterator.from(0) take 20
var n = 0
it1 foreach { n += _ }
assertEquals(190, n)
}
// ticket #429
@Test def fromArray(): Unit = {
val a = List(1, 2, 3, 4).toArray
var xs0 = a.iterator.toList;
var xs1 = a.slice(0, 1).iterator
var xs2 = a.slice(0, 2).iterator
var xs3 = a.slice(0, 3).iterator
var xs4 = a.slice(0, 4).iterator
assertEquals(14, xs0.size + xs1.size + xs2.size + xs3.size + xs4.size)
}
@Test def toSeq(): Unit = {
assertEquals("1x2x3x4x5", List(1, 2, 3, 4, 5).iterator.mkString("x"))
}
@Test def indexOf(): Unit = {
assertEquals(3, List(1, 2, 3, 4, 5).iterator.indexOf(4))
assertEquals(-1, List(1, 2, 3, 4, 5).iterator.indexOf(16))
}
@Test def indexWhere(): Unit = {
assertEquals(3, List(1, 2, 3, 4, 5).iterator.indexWhere { x: Int => x >= 4 })
assertEquals(-1, List(1, 2, 3, 4, 5).iterator.indexWhere { x: Int => x >= 16 })
}
// iterator-iterate-lazy.scala
// was java.lang.UnsupportedOperationException: tail of empty list
@Test def iterateIsSufficientlyLazy(): Unit = {
//Iterator.iterate((1 to 5).toList)(_.tail).takeWhile(_.nonEmpty).toList // suffices
Iterator.iterate((1 to 5).toList)(_.tail).takeWhile(_.nonEmpty).map(_.head).toList
}
// SI-3516
@Test def toStreamIsSufficientlyLazy(): Unit = {
val results = collection.mutable.ListBuffer.empty[Int]
def mkIterator = (1 to 5).iterator map (x => { results += x ; x })
def mkInfinite = Iterator continually { results += 1 ; 1 }
// Stream is strict in its head so we should see 1 from each of them.
val s1 = mkIterator.toStream
val s2 = mkInfinite.toStream
// back and forth without slipping into nontermination.
results += (Stream from 1).toIterator.drop(10).toStream.drop(10).toIterator.next()
assertSameElements(List(1,1,21), results)
}
// SI-9332
@Test def spanExhaustsLeadingIterator(): Unit = {
def it = Iterator.iterate(0)(_ + 1).take(6)
val (x, y) = it.span(_ != 1)
val z = x.toList
assertEquals(1, z.size)
assertFalse(x.hasNext)
assertEquals(1, y.next)
assertFalse(x.hasNext) // was true, after advancing underlying iterator
}
// SI-9913
@Test def `span leading iterator finishes at state -1`(): Unit = {
val (yes, no) = Iterator(1, 2, 3).span(_ => true)
assertFalse(no.hasNext)
assertTrue(yes.hasNext)
}
// SI-9623
@Test def noExcessiveHasNextInJoinIterator: Unit = {
var counter = 0
val exp = List(1,2,3,1,2,3)
def it: Iterator[Int] = new Iterator[Int] {
val parent = List(1,2,3).iterator
def next(): Int = parent.next
def hasNext: Boolean = { counter += 1; parent.hasNext }
}
// Iterate separately
val res = new mutable.ArrayBuffer[Int]
it.foreach(res += _)
it.foreach(res += _)
assertSameElements(exp, res)
assertEquals(8, counter)
// JoinIterator
counter = 0
res.clear
(it ++ it).foreach(res += _)
assertSameElements(exp, res)
assertEquals(8, counter) // was 17
// ConcatIterator
counter = 0
res.clear
(Iterator.empty ++ it ++ it).foreach(res += _)
assertSameElements(exp, res)
assertEquals(8, counter) // was 14
}
// SI-9766
@Test def exhaustedConcatIteratorConcat: Unit = {
def consume[A](i: Iterator[A]) = {
while(i.hasNext) i.next()
}
val joiniter = Iterator.empty ++ Seq(1, 2, 3)
assertTrue(joiniter.hasNext)
consume(joiniter)
val concatiter = joiniter ++ Seq(4, 5, 6)
assertTrue(concatiter.hasNext)
consume(concatiter)
assertFalse(concatiter.hasNext)
val concatFromEmpty = concatiter ++ Seq(7, 8, 9)
assertTrue(concatFromEmpty.hasNext)
consume(concatFromEmpty)
assertFalse(concatFromEmpty.hasNext)
}
}
|
