Add ForestDisjointSetTest

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

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

@@ -0,0 +1,137 @@
+package dev.openrs2.util.collect
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+import kotlin.test.assertNull
+
+object ForestDisjointSetTest {
+    @Test
+    fun testAdd() {
+        val set = ForestDisjointSet<Int>()
+        assertEquals(0, set.elements)
+        assertEquals(0, set.partitions)
+
+        val set1 = set.add(1)
+        assertEquals(1, set.elements)
+        assertEquals(1, set.partitions)
+
+        assertEquals(set1, set.add(1))
+        assertEquals(1, set.elements)
+        assertEquals(1, set.partitions)
+
+        set.add(2)
+        assertEquals(2, set.elements)
+        assertEquals(2, set.partitions)
+    }
+
+    @Test
+    fun testUnionEqualRank() {
+        val set = ForestDisjointSet<Int>()
+
+        val set1 = set.add(1)
+        val set2 = set.add(2)
+        set.union(set1, set2)
+
+        assertEquals(2, set.elements)
+        assertEquals(1, set.partitions)
+    }
+
+    @Test
+    fun testUnionSameRoot() {
+        val set = ForestDisjointSet<Int>()
+
+        val set1 = set.add(1)
+        val set2 = set.add(2)
+        set.union(set1, set2)
+        set.union(set1, set2)
+
+        assertEquals(2, set.elements)
+        assertEquals(1, set.partitions)
+    }
+
+    @Test
+    fun testUnionXRankGreater() {
+        val set = ForestDisjointSet<Int>()
+
+        val set1 = set.add(1)
+        val set2 = set.add(2)
+        val set3 = set.add(3)
+        set.union(set1, set2)
+        set.union(set1, set3)
+
+        assertEquals(3, set.elements)
+        assertEquals(1, set.partitions)
+    }
+
+    @Test
+    fun testUnionYRankGreater() {
+        val set = ForestDisjointSet<Int>()
+
+        val set1 = set.add(1)
+        val set2 = set.add(2)
+        val set3 = set.add(3)
+        set.union(set1, set2)
+        set.union(set3, set1)
+
+        assertEquals(3, set.elements)
+        assertEquals(1, set.partitions)
+    }
+
+    @Test
+    fun testPartitionEquals() {
+        val set = ForestDisjointSet<Int>()
+
+        val set1 = set.add(1)
+        val set2 = set.add(2)
+        assertEquals(set1, set1)
+        assertEquals(set2, set2)
+        assertNotEquals(set1, set2)
+        assertNotEquals(set2, set1)
+    }
+
+    @Test
+    fun testPartitionHashCode() {
+        val set = ForestDisjointSet<Int>()
+
+        assertEquals(1.hashCode(), set.add(1).hashCode())
+        assertEquals(2.hashCode(), set.add(2).hashCode())
+    }
+
+    @Test
+    fun testPartitionToString() {
+        val set = ForestDisjointSet<Int>()
+        assertEquals("1", set.add(1).toString())
+    }
+
+    @Test
+    fun testPartitionIterator() {
+        val set = ForestDisjointSet<Int>()
+
+        val set1 = set.add(1)
+        set.union(set1, set.add(2))
+        set.union(set1, set.add(3))
+
+        assertEquals(setOf(1, 2, 3), set1.asSequence().toSet())
+    }
+
+    @Test
+    fun testIterator() {
+        val set = ForestDisjointSet<Int>()
+
+        set.add(1)
+        set.union(set.add(2), set.add(3))
+
+        assertEquals(setOf(setOf(1), setOf(2, 3)), set.map { it.toSet() }.toSet())
+    }
+
+    @Test
+    fun testGet() {
+        val set = ForestDisjointSet<Int>()
+
+        val set1 = set.add(1)
+        assertEquals(set1, set[1])
+
+        assertNull(set[2])
+    }
+}