Ilya Gorbunov
8e4806725b
- Should be covered by the common stdlib tests - Default implementation is used now
64 lines
1.8 KiB
Kotlin
64 lines
1.8 KiB
Kotlin
/*
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* Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
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* that can be found in the LICENSE file.
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*/
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package runtime.basic.random
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import kotlin.collections.*
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import kotlin.random.*
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import kotlin.system.*
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import kotlin.test.*
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/**
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* Tests that setting the same seed make random generate the same sequence
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*/
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private inline fun <reified T> testReproducibility(seed: Long, generator: () -> T) {
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// Reset seed. This will make Random to start a new sequence
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Random.seed = seed
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val first = Array<T>(50, { i -> generator() }).toList()
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// Reset seed and try again
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Random.seed = seed
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val second = Array<T>(50, { i -> generator() }).toList()
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assertTrue(first == second, "FAIL: got different sequences of generated values " +
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"first: $first, second: $second")
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}
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/**
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* Tests that setting seed makes random generate different sequence.
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*/
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private inline fun <reified T> testDifference(generator: () -> T) {
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Random.seed = 12345678L
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val first = Array<T>(100, { i -> generator() }).toList()
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Random.seed = 87654321L
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val second = Array<T>(100, { i -> generator() }).toList()
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assertTrue(first != second, "FAIL: got the same sequence of generated values " +
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"first: $first, second: $second")
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}
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@Test
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fun testInts() {
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testReproducibility(getTimeMillis(), { Random.nextInt() })
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testReproducibility(Long.MAX_VALUE, { Random.nextInt() })
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}
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@Test
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fun testLong() {
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testReproducibility(getTimeMillis(), { Random.nextLong() })
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testReproducibility(Long.MAX_VALUE, { Random.nextLong() })
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}
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@Test
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fun testDiffInt() = testDifference { Random.nextInt() }
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@Test
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fun testDiffLong() = testDifference { Random.nextLong() }
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@Test
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fun testNextInt() {
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testReproducibility(getTimeMillis(), { Random.nextInt(1000) })
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testReproducibility(1000L, { Random.nextInt(1024) })
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}
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