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How to use edgecase method of io.kotest.property.arbitrary.filter class

Best Kotest code snippet using io.kotest.property.arbitrary.filter.edgecase

dates.kt

Source:dates.kt

...131   minLocalDateTime: LocalDateTime = LocalDateTime.of(1970, 1, 1, 0, 0),132   maxLocalDateTime: LocalDateTime = LocalDateTime.of(2030, 12, 31, 23, 59)133): Arb<LocalDateTime> {134   return arbitrary(135      edgecaseFn = {136         generateSequence {137            val date = localDate(minLocalDateTime.toLocalDate(), maxLocalDateTime.toLocalDate()).edgecase(it)138            val time = localTime().edgecase(it)139            if (date == null || time == null) null else date.atTime(time)140         }.find { !it.isBefore(minLocalDateTime) && !it.isAfter(maxLocalDateTime) }141      },142      sampleFn = {143         generateSequence {144            val date = localDate(minLocalDateTime.toLocalDate(), maxLocalDateTime.toLocalDate()).single(it)145            val time = localTime().single(it)146            date.atTime(time)147         }.first { !it.isBefore(minLocalDateTime) && !it.isAfter(maxLocalDateTime) }148      }149   )150}151/**152 * Arberates a stream of random YearMonth...

collections.kt

Source:collections.kt

...77fun <A> Arb.Companion.list(gen: Gen<A>, range: IntRange = 0..100): Arb<List<A>> {78   check(!range.isEmpty())79   check(range.first >= 0)80   return arbitrary(81      edgecaseFn = { rs ->82         val emptyList = emptyList<A>()83         val singleList: List<A>? = when (gen) {84            is Arb -> (gen.edgecase(rs) ?: gen.next(rs))?.let { listOf(it) }85            is Exhaustive -> gen.values.firstOrNull()?.let { listOf(it) }86         }87         val repeatedList: List<A>? = when {88            range.last < 2 -> null // too small for repeats89            gen is Arb -> (gen.edgecase(rs) ?: gen.next(rs))?.let { a -> List(max(2, range.first)) { a } }90            gen is Exhaustive -> gen.values.firstOrNull()?.let { a -> List(max(2, range.first)) { a } }91            else -> null92         }93         listOfNotNull(emptyList, singleList, repeatedList).filter { it.size in range }.distinct().random(rs.random)94      },95      shrinker = ListShrinker(range),96      sampleFn = { rs ->97         val targetSize = rs.random.nextInt(range)98         gen.generate(rs).take(targetSize).toList().map { it.value }99      }100   )101}102/**103 * Returns an [Arb] whose of values are a list of values generated by the current arb....

strings.kt

Source:strings.kt

...21      val size = rs.random.nextInt(minSize..maxSize)22      codepoints.take(size, rs).joinToString("") { it.asString() }23   }.withEdgecaseFn { rs ->24      if (minSize == maxSize) null else {25         val lowCodePoint = codepoints.edgecase(rs)26         val min = lowCodePoint?.let { cp -> List(minSize) { cp.asString() }.joinToString("") }27         val minPlus1 = lowCodePoint?.let { cp -> List(minSize + 1) { cp.asString() }.joinToString("") }28         val edgeCases = listOfNotNull(min, minPlus1)29            .filter { it.length in minSize..maxSize }30         if (edgeCases.isEmpty()) null else edgeCases.random(rs.random)31      }32   }.withShrinker(StringShrinkerWithMin(minSize))33      .withClassifier(StringClassifier(minSize, maxSize))34      .build()35}36/**37 * Returns an [Arb] where each random value is a String which has a length in the given range.38 * By default the arb uses a [ascii] codepoint generator, but this can be substituted39 * with any codepoint generator. There are many available, such as [katakana] and so on....

FilterTest.kt

Source:FilterTest.kt

...25   }26   test("should filter edge cases") {27      val arb = Arb.int(1..10).withEdgecases(1, 2, 3).filter { it % 2 == 0 }28      val edgeCases = arb29         .generate(RandomSource.seeded(1234L), EdgeConfig(edgecasesGenerationProbability = 1.0))30         .take(5)31         .map { it.value }32         .toList()33      edgeCases shouldContainExactly listOf(2, 2, 2, 2, 2)34   }35   test("should be stack safe") {36      val arb = object : Arb<Int>() {37         override fun edgecase(rs: RandomSource): Int? = null38         override fun sample(rs: RandomSource): Sample<Int> = Sample(rs.random.nextInt())39      }40      shouldNotThrow<StackOverflowError> {41         arb.filter { it % 2 == 0 }.take(1000000).toList()42      }43   }44   test("should apply filter to shrinks") {45      val arbEvenInts = Arb.int(-100..100).filter { it % 2 == 0 }46      val oddNumbers = (-100..100).filter { it % 2 != 0 }47      arbEvenInts.samples().take(100).forAll { sample ->48         sample.shrinks.value() shouldNotBeIn oddNumbers49         sample.shrinks.children.value.forAll {50            it.value() shouldNotBeIn oddNumbers51         }...

BigDecimalTest.kt

Source:BigDecimalTest.kt

...8import io.kotest.matchers.shouldBe9import io.kotest.property.Arb10import io.kotest.property.arbitrary.bigDecimal11import io.kotest.property.arbitrary.bigDecimalDefaultEdgecases12import io.kotest.property.arbitrary.edgecases13import io.kotest.property.arbitrary.take14import java.math.BigDecimal15import java.math.RoundingMode16import java.util.concurrent.TimeUnit17class BigDecimalTest : FunSpec({18   test("Arb.bigDecimal(min, max) should generate bigDecimal between given range") {19      val min = BigDecimal.valueOf(123)20      val max = BigDecimal.valueOf(555)21      Arb.bigDecimal(min, max).take(100).forAll {22         (it >= min && it <= max) shouldBe true23      }24   }25   test("Arb.bigDecimal(scale, rounding) should generate bigDecimal of given scale") {26      Arb.bigDecimal(4, RoundingMode.CEILING).take(100).forAll {27         it.scale() shouldBe 428      }29   }30   test("Arb.bigDecimal(min, max) for large value should complete with in few seconds") {31      shouldCompleteWithin(5, TimeUnit.SECONDS) {32         Arb.bigDecimal(BigDecimal.valueOf(-100_000.00), BigDecimal.valueOf(100_000.00)).take(100).forEach { _ ->33         }34      }35   }36   test("bigDecimalDefaultEdgecases should contain zeros with differing precision") {37      bigDecimalDefaultEdgecases.shouldContain(BigDecimal("0.00"))38      bigDecimalDefaultEdgecases.shouldContain(BigDecimal("0"))39   }40   test("Arb.bigDecimal(min, max) should always contain min as edgecase but not max") {41      val min = BigDecimal.valueOf(123)42      val max = BigDecimal.valueOf(555)43      val actualEdgecases = Arb.bigDecimal(min = min, max = max).edgecases()44      actualEdgecases.shouldContain(min)45      actualEdgecases.shouldNotContain(max)46   }47   test("Arb.bigDecimal(min, max) should only include default edgecases that are in range [min, max)") {48      val min = BigDecimal.valueOf(0)49      val max = BigDecimal.valueOf(5)50      val expectedEdgecases = bigDecimalDefaultEdgecases51         .filter { min <= it && it < max }52      Arb.bigDecimal(min = min, max = max).edgecases().shouldContainAll(expectedEdgecases)53   }54})...

filter.kt

Source:filter.kt

...11 * the predicate.12 */13fun <A> Arb<A>.filter(predicate: (A) -> Boolean): Arb<A> = trampoline { sampleA ->14   object : Arb<A>() {15      override fun edgecase(rs: RandomSource): A? =16         sequenceOf(sampleA.value)17            .plus(generateSequence { this@filter.edgecase(rs) })18            .take(PropertyTesting.maxFilterAttempts)19            .filter(predicate)20            .firstOrNull()21      override fun sample(rs: RandomSource): Sample<A> {22         val sample = sequenceOf(sampleA).plus(this@filter.samples(rs)).filter { predicate(it.value) }.first()23         return Sample(sample.value, sample.shrinks.filter(predicate) ?: RTree({ sample.value }))24      }25   }26}27/**28 * @return a new [Arb] by filtering this arbs output by the negated function [f]29 */30fun <A> Arb<A>.filterNot(f: (A) -> Boolean): Arb<A> = filter { !f(it) }31/**...

distinct.kt

Source:distinct.kt

...5import io.kotest.property.Sample6@DelicateKotest7fun <A> Arb<A>.distinct(attempts: Int = 100) = object : Arb<A>() {8   private val seen = mutableSetOf<A>()9   override fun edgecase(rs: RandomSource): A? = this@distinct.edgecase(rs)10   override fun sample(rs: RandomSource): Sample<A> {11      var iterations = 012      return generateSequence {13         if (iterations++ < attempts) this@distinct.sample(rs) else null14      }.filter { seen.add(it.value) }.first()15   }16}

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