refactor: CircularQueue (#5354)

src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java

@@ -0,0 +1,106 @@
+package com.thealgorithms.datastructures.queues;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class CircularQueueTest {
+
+    @Test
+    void testEnQueue() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        cq.enQueue(3);
+
+        assertEquals(1, cq.peek());
+        assertTrue(cq.isFull());
+    }
+
+    @Test
+    void testDeQueue() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        cq.enQueue(3);
+
+        assertEquals(1, cq.deQueue());
+        assertEquals(2, cq.peek());
+        assertFalse(cq.isFull());
+    }
+
+    @Test
+    void testIsEmpty() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        assertTrue(cq.isEmpty());
+
+        cq.enQueue(1);
+        assertFalse(cq.isEmpty());
+    }
+
+    @Test
+    void testIsFull() {
+        CircularQueue<Integer> cq = new CircularQueue<>(2);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        assertTrue(cq.isFull());
+
+        cq.deQueue();
+        assertFalse(cq.isFull());
+    }
+
+    @Test
+    void testPeek() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+
+        assertEquals(1, cq.peek());
+        assertEquals(1, cq.peek()); // Ensure peek doesn't remove the element
+    }
+
+    @Test
+    void testDeleteQueue() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        cq.deleteQueue();
+
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalStateException.class, cq::peek);
+    }
+
+    @Test
+    void testEnQueueOnFull() {
+        CircularQueue<Integer> cq = new CircularQueue<>(2);
+        cq.enQueue(1);
+        cq.enQueue(2);
+
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalStateException.class, () -> cq.enQueue(3));
+    }
+
+    @Test
+    void testDeQueueOnEmpty() {
+        CircularQueue<Integer> cq = new CircularQueue<>(2);
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalStateException.class, cq::deQueue);
+    }
+
+    @Test
+    void testPeekOnEmpty() {
+        CircularQueue<Integer> cq = new CircularQueue<>(2);
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalStateException.class, cq::peek);
+    }
+
+    @Test
+    void testSize() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+
+        assertEquals(2, cq.size());
+
+        cq.deQueue();
+        assertEquals(1, cq.size());
+    }
+}