Add IterableUtilsTest

Signed-off-by: Graham <gpe@openrs2.dev>

util/src/test/java/dev/openrs2/util/collect/IterableUtilsTest.kt

@@ -0,0 +1,55 @@
+package dev.openrs2.util.collect
+
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+object IterableUtilsTest {
+    @Test
+    fun testRemoveFirst() {
+        val list = mutableListOf(1, 2, 3)
+        assertEquals(1, list.removeFirst())
+        assertEquals(listOf(2, 3), list)
+
+        assertEquals(2, list.removeFirst())
+        assertEquals(listOf(3), list)
+
+        assertEquals(3, list.removeFirst())
+        assertEquals(emptyList<Int>(), list)
+
+        assertThrows<NoSuchElementException> {
+            list.removeFirst()
+        }
+    }
+
+    @Test
+    fun testRemoveFirstOrNull() {
+        val list = mutableListOf(1, 2, 3)
+        assertEquals(1, list.removeFirstOrNull())
+        assertEquals(listOf(2, 3), list)
+
+        assertEquals(2, list.removeFirstOrNull())
+        assertEquals(listOf(3), list)
+
+        assertEquals(3, list.removeFirstOrNull())
+        assertEquals(emptyList<Int>(), list)
+
+        assertNull(list.removeFirstOrNull())
+    }
+
+    @Test
+    fun testRemoveFirstMatching() {
+        val list = mutableListOf(1, 2, 2, 3)
+        assertTrue(list.removeFirst { it == 2 })
+        assertEquals(listOf(1, 2, 3), list)
+
+        assertTrue(list.removeFirst { it == 2 })
+        assertEquals(listOf(1, 3), list)
+
+        assertFalse(list.removeFirst { it == 2 })
+        assertEquals(listOf(1, 3), list)
+    }
+}