Franck Rasolo
84 lines
2.6 KiB
Kotlin
84 lines
2.6 KiB
Kotlin
package test.sequences
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import java.util.ArrayList
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import kotlin.sequences.asSequence
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import kotlin.sequences.sequence
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import kotlin.util.arrayList
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import kotlin.util.fold
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import kotlin.test.assertEquals
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import org.junit.Test
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class SequenceTest {
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Test fun filterReturnsTheExpectedSequence() {
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val actual = (1..10).asSequence().filter { it % 2 == 0 }.toList()
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assertEquals(arrayList(2, 4, 6, 8, 10), actual)
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}
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Test fun filterReturnsAnEmptySequenceWhenNoElementMatchesThePredicate() {
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val actual = sequence(1, 3, 4, 7).filter { it > 7 }.toList()
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assertEquals(ArrayList<Int>(), actual)
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}
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Test fun foldReturnsTheExpectedReduction() {
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val actual = (1..10).asSequence().filter { it % 2 == 1 }.fold(0, sum)
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assertEquals(1 + 3 + 5 + 7 + 9, actual)
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}
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Test fun foldReturnsTheInitialValueForAnEmptySequence() {
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val initialValue = 0
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val actual = (1..0).asSequence().fold(initialValue, sum)
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assertEquals(initialValue, actual)
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}
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Test fun mapReturnsTheExpectedTransformation() {
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val actual = sequence(1, 3, 4, 7).map { it * 2 }.toList()
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assertEquals(arrayList(2, 6, 8, 14), actual)
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}
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Test fun takeReturnsTheFirstNElements() {
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var actual = (1..5).asSequence().take(3).toList()
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assertEquals(arrayList(1, 2, 3), actual)
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}
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Test fun takeReturnsTheEntireSequenceWhenTheNumberOfElementsIsGreaterThanItsSize() {
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val actual = sequence(1, 2).take(3).toList()
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assertEquals(arrayList(1, 2), actual)
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}
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Test fun takeReturnsAnEmptySequenceForAnEmptySequence() {
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val actual = (1..0).asSequence().take(3).toList()
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assertEquals(ArrayList<Int>(), actual)
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}
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Test fun takeReturnsAnEmptySequenceWhenTheNumberOfElementsToExtractIsZero() {
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val actual = sequence(1, 2).take(0).toList()
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assertEquals(ArrayList<Int>(), actual)
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}
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Test fun takeReturnsAnEmptySequenceWhenTheNumberOfElementsToExtractIsNegative() {
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val actual = sequence(1, 2).take(-1).toList()
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assertEquals(ArrayList<Int>(), actual)
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}
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Test fun takeWhileReturnsTheFirstElementsMatchingAGivenPredicate() {
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val actual = sequence(1, 2, 3, 4, 1, 2, 3, 4).takeWhile { it < 3 }.toList()
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assertEquals(arrayList(1, 2), actual)
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}
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Test fun takeWhileReturnsTheEntireSequenceWhenThePredicateMatchesAllElements() {
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val actual = sequence(1, 2, 3).takeWhile { it < 9 }.toList()
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assertEquals(arrayList(1, 2, 3), actual)
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}
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Test fun takeWhileReturnsAnEmptySequenceWhenThePredicateMatchesNothing() {
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val actual = sequence(1, 2, 3).takeWhile { it < 0 }.toList()
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assertEquals(ArrayList<Int>(), actual)
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}
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private val sum = { (a : Int, b : Int) -> a + b }
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}
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