KT-57617 Delegate iterators of reversed list views to underlying list iterators
Improve the performance of reversed list view iterators by delegating to underlying list iterators instead of using implementations provided by the AbstractList. Latter use AbstractList::get(index: Int) to implement next() and previous() methods and depending on the underlying list's implementation it may lead to worse performance. The change also improves reversed list views test coverage.
This commit is contained in:
Filipp Zhinkin
committed by
Space Team
Space Team
parent
247f5529d2
commit
d0847f2519
@@ -1,12 +1,11 @@
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/*
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* Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
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* Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
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* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
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*/
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package test.collections
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import test.collections.behaviors.listBehavior
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import test.collections.compare
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import kotlin.test.*
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class ReversedViewsTest {
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@@ -23,6 +22,14 @@ class ReversedViewsTest {
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}
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}
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@Test fun testMutableBehavior() {
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val original = mutableListOf(2L, 3L, Long.MAX_VALUE)
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val reversed = original.reversed()
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compare(reversed, original.asReversed()) {
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listBehavior()
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}
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}
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@Test fun testSimple() {
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assertEquals(listOf(3, 2, 1), listOf(1, 2, 3).asReversed())
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assertEquals(listOf(3, 2, 1), listOf(1, 2, 3).asReversed().toList())
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@@ -147,11 +154,6 @@ class ReversedViewsTest {
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assertTrue { 1 in mutableListOf(1, 2, 3).asReversed() }
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}
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@Test fun testIndexOf() {
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assertEquals(2, listOf(1, 2, 3).asReversed().indexOf(1))
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assertEquals(2, mutableListOf(1, 2, 3).asReversed().indexOf(1))
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}
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@Test fun testBidirectionalModifications() {
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val original = mutableListOf(1, 2, 3, 4)
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val reversed = original.asReversed()
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@@ -165,47 +167,178 @@ class ReversedViewsTest {
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assertEquals(listOf(3, 2), reversed)
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}
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@Test fun testGetIOOB() {
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val success = try {
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listOf(1, 2, 3).asReversed().get(3)
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true
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} catch (expected: IndexOutOfBoundsException) {
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false
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@Test fun testIndexOf() {
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assertEquals(2, listOf(1, 2, 3).asReversed().indexOf(1))
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assertEquals(2, mutableListOf(1, 2, 3).asReversed().indexOf(1))
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assertEquals(-1, listOf(1, 2, 3).asReversed().indexOf(0))
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assertEquals(-1, mutableListOf(1, 2, 3).asReversed().indexOf(0))
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}
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@Test fun testLastIndexOf() {
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assertEquals(2, listOf(1, 2, 3).asReversed().indexOf(1))
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assertEquals(2, mutableListOf(1, 2, 3).asReversed().indexOf(1))
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assertEquals(-1, listOf(1, 2, 3).asReversed().lastIndexOf(0))
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assertEquals(-1, mutableListOf(1, 2, 3).asReversed().lastIndexOf(0))
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}
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@Test fun testIteratorAdd() {
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val original = mutableListOf(1, 2, 4)
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val reversedView = original.asReversed()
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val iter = reversedView.listIterator()
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val reversedCopy = original.reversed().toMutableList()
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val copyIter = reversedCopy.listIterator()
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compare(copyIter, iter) {
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propertyEquals { add(5) }
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propertyEquals { previousIndex() }
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propertyEquals { nextIndex() }
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propertyEquals { next() }
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}
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assertEquals(reversedCopy, reversedView)
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assertEquals(listOf(1, 2, 4, 5), original)
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compare(copyIter, iter) {
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propertyEquals { add(3) }
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propertyEquals { previousIndex() }
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propertyEquals { nextIndex() }
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propertyEquals { previous() }
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}
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assertFalse(success)
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iter.seekEnd()
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iter.add(0)
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assertEquals(listOf(5, 4, 3, 2, 1, 0), reversedView)
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assertEquals(listOf(0, 1, 2, 3, 4, 5), original)
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}
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@Test fun testIteratorRemove() {
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val original = mutableListOf(0, 1, 2, 3, 4)
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val reversedView = original.asReversed()
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val iter = reversedView.listIterator()
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val reversedCopy = original.reversed().toMutableList()
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val copyIter = reversedCopy.listIterator()
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compare(copyIter, iter) {
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propertyFailsWith<IllegalStateException> { remove() }
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propertyEquals {
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next()
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remove()
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}
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propertyEquals { previousIndex() }
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propertyEquals { nextIndex() }
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propertyFailsWith<IllegalStateException> { remove() }
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propertyEquals { next() }
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}
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assertEquals(reversedCopy, reversedView)
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assertEquals(listOf(0, 1, 2, 3), original)
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compare(copyIter, iter) {
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propertyEquals {
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next()
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remove()
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}
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propertyEquals { previousIndex() }
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propertyEquals { nextIndex() }
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propertyEquals { previous() }
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}
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assertEquals(reversedCopy, reversedView)
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assertEquals(listOf(0, 1, 3), original)
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iter.seekEnd()
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iter.remove()
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assertEquals(listOf(3, 1), reversedView)
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assertEquals(listOf(1, 3), original)
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}
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@Test fun testIteratorSet() {
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val original = mutableListOf(2, 3, 4)
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val iter = original.asReversed().listIterator()
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while (iter.hasNext()) {
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val v = iter.next()
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iter.set(v * v)
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}
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assertEquals(listOf(4, 9, 16), original)
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}
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@Test fun testGetIOOB() {
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assertFailsWith<IndexOutOfBoundsException> {
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listOf(1, 2, 3).asReversed().get(3)
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}.let { exception ->
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// we actually don't care about the exact wording,
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// we just need the index to be not confusing
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assertContains(exception.message!!, "index 3")
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}
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assertFailsWith<IndexOutOfBoundsException> {
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mutableListOf(1, 2, 3).asReversed().get(3)
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}.let { exception ->
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// we actually don't care about the exact wording,
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// we just need the index to be not confusing
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assertContains(exception.message!!, "index 3")
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}
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}
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@Test fun testSetIOOB() {
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val success = try {
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mutableListOf(1, 2, 3).asReversed().set(3, 0)
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true
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} catch(expected: IndexOutOfBoundsException) {
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false
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assertFailsWith<IndexOutOfBoundsException> {
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mutableListOf(1, 2, 3, 4).asReversed().set(4, 0)
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}.let { exception ->
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// we actually don't care about the exact wording,
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// we just need the index to be not confusing
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assertContains(exception.message!!, "index 4")
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}
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assertFalse(success)
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}
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@Test fun testAddIOOB() {
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val success = try {
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assertFailsWith<IndexOutOfBoundsException> {
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mutableListOf(1, 2, 3).asReversed().add(4, 0)
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true
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} catch(expected: IndexOutOfBoundsException) {
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false
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}.let { exception ->
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// we actually don't care about the exact wording,
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// we just need the index to be not confusing
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assertContains(exception.message!!, "index 4")
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}
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assertFalse(success)
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}
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@Test fun testRemoveIOOB() {
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val success = try {
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assertFailsWith<IndexOutOfBoundsException> {
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mutableListOf(1, 2, 3).asReversed().removeAt(3)
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true
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} catch(expected: IndexOutOfBoundsException) {
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false
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}.let { exception ->
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// we actually don't care about the exact wording,
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// we just need the index to be not confusing
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assertContains(exception.message!!, "index 3")
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}
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}
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@Test fun testIteratorNSEOnNext() {
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assertFailsWith<NoSuchElementException> {
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val it = listOf(1, 2, 3).asReversed().iterator()
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it.seekEnd()
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it.next()
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}
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assertFalse(success)
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assertFailsWith<NoSuchElementException> {
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val it = mutableListOf(1, 2, 3).asReversed().iterator()
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it.seekEnd()
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it.next()
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}
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}
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@Test fun testIteratorNSEOnPrevious() {
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assertFailsWith<NoSuchElementException> {
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listOf(1, 2, 3).asReversed().listIterator().previous()
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}
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assertFailsWith<NoSuchElementException> {
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mutableListOf(1, 2, 3).asReversed().listIterator().previous()
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}
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}
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}
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private fun Iterator<*>.seekEnd() {
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while (hasNext()) {
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next()
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}
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}
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