Extract Double.isIntegral() - a function that checks if a number is integral

Author: rhaendel

src/main/kotlin/de/ronny_h/aoc/extensions/IntegralNumbers.kt

@@ -0,0 +1,8 @@
+package de.ronny_h.aoc.extensions
+
+import kotlin.math.floor
+
+/**
+ * Checks if a Double number is integral.
+ */
+fun Double.isIntegral() = floor(this) == this

src/main/kotlin/de/ronny_h/aoc/year24/day13/ClawContraption.kt

@@ -1,7 +1,7 @@
 package de.ronny_h.aoc.year24.day13
 
 import de.ronny_h.aoc.AdventOfCode
-import kotlin.math.floor
+import de.ronny_h.aoc.extensions.isIntegral
 
 fun main() = ClawContraption().run(33427, 91649162972270)
 
@@ -76,5 +76,3 @@ class ClawContraption : AdventOfCode<Long>(2024, 13) {
 }
 
 data class ClawMachine(val ax: Int, val ay: Int, val bx: Int, val by: Int, val x: Int, val y: Int)
-
-private fun Double.isIntegral() = floor(this) == this

src/test/kotlin/de/ronny_h/aoc/extensions/IntegralNumbersTest.kt

@@ -0,0 +1,31 @@
+package de.ronny_h.aoc.extensions
+
+import io.kotest.core.spec.style.StringSpec
+import io.kotest.data.forAll
+import io.kotest.data.row
+import io.kotest.matchers.shouldBe
+
+class IntegralNumbersTest : StringSpec({
+
+    "isIntegral is true for integral numbers" {
+        forAll(
+            row(0.0),
+            row(7.000000000),
+            row(42.0),
+            row(70000001.0),
+        ) { value ->
+            value.isIntegral() shouldBe true
+        }
+    }
+
+    "isIntegral is false for non-integral numbers" {
+        forAll(
+            row(0.5),
+            row(0.0000001),
+            row(7.0000001),
+            row(7.9),
+        ) { value ->
+            value.isIntegral() shouldBe false
+        }
+    }
+})