A function that tests a list for symmetries

Author: rhaendel

src/main/kotlin/de/ronny_h/extensions/Symmetries.kt

@@ -0,0 +1,8 @@
+package de.ronny_h.extensions
+
+fun List<Int>.isSymmetrical(): Boolean {
+    for (i in 0..<size / 2) {
+        if (this[i] != this[lastIndex - i]) return false
+    }
+    return true
+}

src/test/kotlin/de/ronny_h/extensions/SymmetriesTest.kt

@@ -0,0 +1,22 @@
+package de.ronny_h.extensions
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+
+class SymmetriesTest {
+
+    @Test
+    fun `an empty list is symmetrical`() {
+        assertThat(listOf<Int>().isSymmetrical()).isTrue()
+    }
+
+    @Test
+    fun `a symmetrical list is symmetrical`() {
+        assertThat(listOf(1, 2, 3, 2, 1).isSymmetrical()).isTrue()
+    }
+
+    @Test
+    fun `a asymmetrical list is not symmetrical`() {
+        assertThat(listOf(4, 2, 3, 2, 1).isSymmetrical()).isFalse()
+    }
+}