Enhance docs, add tests in HashMapCuckooHashing (#5975)

src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java

@@ -1,94 +0,0 @@
-package com.thealgorithms.datastructures.hashmap;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
-
-import com.thealgorithms.datastructures.hashmap.hashing.HashMapCuckooHashing;
-import org.junit.jupiter.api.Test;
-
-class HashMapCuckooHashingTest {
-
-    @Test
-    void insertKey() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        assertEquals(0, hashTable.getNumberOfKeysInTable());
-
-        hashTable.insertKey2HashTable(3);
-
-        assertEquals(1, hashTable.getNumberOfKeysInTable());
-    }
-
-    @Test
-    void getKeyIndex() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(8);
-        hashTable.insertKey2HashTable(4);
-
-        assertNotEquals(-1, hashTable.findKeyInTable(8));
-    }
-
-    @Test
-    void containsKey() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(8);
-        boolean contains = hashTable.checkTableContainsKey(8);
-
-        assertTrue(contains);
-    }
-
-    @Test
-    void removeKey() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(3);
-
-        int initialSize = hashTable.getNumberOfKeysInTable();
-
-        hashTable.deleteKeyFromHashTable(3);
-
-        assertEquals(initialSize - 1, hashTable.getNumberOfKeysInTable());
-    }
-
-    @Test
-    void removeNone() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        try {
-            hashTable.deleteKeyFromHashTable(3);
-        } catch (Exception e) {
-            assertTrue(true);
-            return;
-        }
-        fail();
-    }
-
-    @Test
-    void reHashTableIncreasesTableSize() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        int initialSize = hashTable.getNumberOfKeysInTable();
-
-        hashTable.reHashTableIncreasesTableSize();
-
-        assertEquals(initialSize * 2, hashTable.getNumberOfKeysInTable());
-    }
-
-    @Test
-    void hashFunctionsAreDifferent() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(33);
-
-        assertNotEquals(hashTable.hashFunction1(3), hashTable.hashFunction2(3));
-    }
-
-    @Test
-    void avoidInfiniteLoops() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(0);
-        hashTable.insertKey2HashTable(10);
-        hashTable.insertKey2HashTable(100);
-
-        assertTrue(hashTable.checkTableContainsKey(0));
-        assertTrue(hashTable.checkTableContainsKey(10));
-        assertTrue(hashTable.checkTableContainsKey(100));
-    }
-}

src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashingTest.java

@@ -0,0 +1,140 @@
+package com.thealgorithms.datastructures.hashmap.hashing;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+class HashMapCuckooHashingTest {
+
+    @Test
+    void insertKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        assertEquals(0, hashTable.getNumberOfKeysInTable());
+
+        hashTable.insertKey2HashTable(3);
+        assertEquals(1, hashTable.getNumberOfKeysInTable());
+    }
+
+    @Test
+    void getKeyIndex() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(8);
+        hashTable.insertKey2HashTable(4);
+
+        assertNotEquals(-1, hashTable.findKeyInTable(8));
+    }
+
+    @Test
+    void containsKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(8);
+        boolean contains = hashTable.checkTableContainsKey(8);
+
+        assertTrue(contains);
+    }
+
+    @Test
+    void removeKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(3);
+
+        int initialSize = hashTable.getNumberOfKeysInTable();
+        hashTable.deleteKeyFromHashTable(3);
+
+        assertEquals(initialSize - 1, hashTable.getNumberOfKeysInTable());
+    }
+
+    @Test
+    void removeNone() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        try {
+            hashTable.deleteKeyFromHashTable(3);
+        } catch (Exception e) {
+            assertTrue(true);
+            return;
+        }
+        Assertions.fail("Expected exception when trying to delete a non-existing key.");
+    }
+
+    @Test
+    void reHashTableIncreasesTableSize() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(1);
+        hashTable.insertKey2HashTable(2);
+        hashTable.insertKey2HashTable(3);
+        hashTable.insertKey2HashTable(4);
+        hashTable.insertKey2HashTable(5);
+        hashTable.insertKey2HashTable(6);
+        hashTable.insertKey2HashTable(7);
+        hashTable.insertKey2HashTable(8);
+        hashTable.insertKey2HashTable(9);
+        hashTable.insertKey2HashTable(10); // This should trigger rehashing
+
+        assertEquals(10, hashTable.getNumberOfKeysInTable());
+    }
+
+    @Test
+    void hashFunctionsAreDifferent() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(33);
+
+        assertNotEquals(hashTable.hashFunction1(3), hashTable.hashFunction2(3), "Hash functions should produce different indices.");
+    }
+
+    @Test
+    void avoidInfiniteLoops() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(0);
+        hashTable.insertKey2HashTable(10);
+        hashTable.insertKey2HashTable(100);
+
+        assertTrue(hashTable.checkTableContainsKey(0));
+        assertTrue(hashTable.checkTableContainsKey(10));
+        assertTrue(hashTable.checkTableContainsKey(100));
+    }
+
+    @Test
+    void testLoadFactor() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        for (int i = 1; i <= 8; i++) { // Insert 8 keys to test load factor
+            hashTable.insertKey2HashTable(i);
+        }
+        assertEquals(8, hashTable.getNumberOfKeysInTable());
+        // Check that rehashing occurs when a 9th key is added
+        hashTable.insertKey2HashTable(9);
+        assertTrue(hashTable.getNumberOfKeysInTable() > 8, "Load factor exceeded, table should have been resized.");
+    }
+
+    @Test
+    void testDeleteNonExistentKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(1);
+        hashTable.insertKey2HashTable(2);
+
+        Exception exception = null;
+        try {
+            hashTable.deleteKeyFromHashTable(3); // Try deleting a non-existent key
+        } catch (IllegalArgumentException e) {
+            exception = e; // Capture the exception
+        }
+        assertNotNull(exception, "Expected an IllegalArgumentException when deleting a non-existent key.");
+    }
+
+    @Test
+    void testInsertDuplicateKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(1);
+        Exception exception = null;
+
+        try {
+            hashTable.insertKey2HashTable(1); // Attempt to insert duplicate key
+        } catch (IllegalArgumentException e) {
+            exception = e; // Capture the exception
+        }
+        assertNotNull(exception, "Expected an IllegalArgumentException for duplicate key insertion.");
+    }
+}