fix: Missing values near boundary for instant and duration generators (…

…#229)

Thanks to @mmiikkkkaa

generator/stdlib/src/jvmMain/kotlin/com/github/jcornaz/kwik/generator/stdlib/DateTime.kt

@@ -38,7 +38,9 @@ public fun Generator.Companion.instants(
     return Generator { random: Random ->
         val seconds =
             if (min.epochSecond == max.epochSecond) min.epochSecond
-            else random.nextLong(from = min.epochSecond, until = max.epochSecond)
+            // also include the max value (since "until" is not inclusive) by add 1
+            // (since Instant.MAX.epoch second is always lower than Long.MAX_VALUE there no overflow error possible)
+            else random.nextLong(from = min.epochSecond, until = max.epochSecond + 1)
 
         val instant = Instant.ofEpochSecond(seconds)
 
@@ -79,7 +81,10 @@ public fun Generator.Companion.durations(
     return Generator { random: Random ->
         val seconds =
             if (min.seconds == max.seconds) min.seconds
-            else random.nextLong(from = min.seconds, until = max.seconds)
+            // also include the max value (since "until" is not inclusive) by add 1,
+            // but only if Long.MAX_VALUE is not reached
+            else random.nextLong(from = min.seconds, until =
+                if (max.seconds == Long.MAX_VALUE) Long.MAX_VALUE else  max.seconds + 1)
 
         val duration = Duration.ofSeconds(seconds)
 

generator/stdlib/src/jvmTest/kotlin/com/github/jcornaz/kwik/generator/stdlib/DateTimeGeneratorTest.kt

@@ -85,6 +85,20 @@ class DurationGeneratorTest : AbstractGeneratorTest() {
         val min = Duration.ofSeconds(1)
         assertTrue(Generator.durations(min = min).randomSequence(0).take(50).any { it == min })
     }
+
+    @Test
+    fun `generate durations with max seconds included`() {
+        val min = Duration.ofSeconds(1, MAX_NANOSECONDS - 2)
+        val max = Duration.ofSeconds(2, MAX_NANOSECONDS)
+        assertTrue(Generator.durations(min = min, max = max).randomSequence(0).take(50).filterNot { it == max }.any { it.seconds == max.seconds})
+    }
+
+    @Test
+    fun `do not created boundary errors if max seconds is long MAX_VALUE`() {
+        val min = Duration.ofSeconds(Long.MAX_VALUE - 1 )
+        val max = Duration.ofSeconds(Long.MAX_VALUE, MAX_NANOSECONDS)
+        assertTrue(Generator.durations(min = min, max = max).randomSequence(0).take(50).filterNot { it == max }.none { it.seconds == max.seconds })
+    }
 }
 
 class InstantGeneratorTest : AbstractGeneratorTest() {
@@ -161,6 +175,13 @@ class InstantGeneratorTest : AbstractGeneratorTest() {
         assertTrue(Generator.instants(min = min, max = max).randomSequence(0).take(50).any { it == min })
     }
 
+    @Test
+    fun `generate instants with max seconds included`() {
+        val min = Instant.ofEpochSecond(1)
+        val max = Instant.ofEpochSecond(2, MAX_NANOSECONDS)
+        assertTrue(Generator.instants(min = min, max = max).randomSequence(0).take(50).filterNot { it == max }.any { it.epochSecond == max.epochSecond })
+    }
+
     @Test
     fun `generate values within complete nanos range if epochsecond is not min boundary`() {
         val minNanoBoundary = MAX_NANOSECONDS - 10
@@ -184,7 +205,6 @@ class InstantGeneratorTest : AbstractGeneratorTest() {
             .filter { it.epochSecond < max.epochSecond }
             .any { it.nano > maxNanoBoundary })
     }
-
 }
 
 class LocalTimeGeneratorTest : AbstractGeneratorTest() {