用 java语言以测试驱动开发实现循环队列

以下是用 Java 语言实现循环队列的示例代码，采用测试驱动开发方式：

import org.junit.Test;
import static org.junit.Assert.*;

public class CircularQueueTest {

    @Test
    public void testEnqueueAndDequeue() {
        CircularQueue queue = new CircularQueue(3);
        assertTrue(queue.isEmpty());
        assertFalse(queue.isFull());
        queue.enqueue(1);
        queue.enqueue(2);
        queue.enqueue(3);
        assertTrue(queue.isFull());
        assertFalse(queue.isEmpty());
        assertEquals(1, queue.dequeue());
        assertEquals(2, queue.dequeue());
        assertEquals(3, queue.dequeue());
        assertTrue(queue.isEmpty());
        assertFalse(queue.isFull());
    }

    @Test
    public void testEnqueueAndDequeueWithWrapAround() {
        CircularQueue queue = new CircularQueue(3);
        assertTrue(queue.isEmpty());
        assertFalse(queue.isFull());
        queue.enqueue(1);
        queue.enqueue(2);
        assertEquals(1, queue.dequeue());
        queue.enqueue(3);
        assertTrue(queue.isFull());
        assertFalse(queue.isEmpty());
        assertEquals(2, queue.dequeue());
        assertEquals(3, queue.dequeue());
        assertTrue(queue.isEmpty());
        assertFalse(queue.isFull());
    }

    @Test
    public void testEnqueueAndDequeueWithOverwrite() {
        CircularQueue queue = new CircularQueue(3);
        assertTrue(queue.isEmpty());
        assertFalse(queue.isFull());
        queue.enqueue(1);
        queue.enqueue(2);
        queue.enqueue(3);
        queue.enqueue(4);
        assertTrue(queue.isFull());
        assertFalse(queue.isEmpty());
        assertEquals(2, queue.dequeue());
        assertEquals(3, queue.dequeue());
        assertEquals(4, queue.dequeue());
        assertTrue(queue.isEmpty());
        assertFalse(queue.isFull());
    }
}

class CircularQueue {
    private int[] buffer;
    private int front;
    private int rear;
    private int size;

    public CircularQueue(int capacity) {
        buffer = new int[capacity];
        front = 0;
        rear = 0;
        size = 0;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    public boolean isFull() {
        return size == buffer.length;
    }

    public void enqueue(int value) {
        if (isFull()) {
            dequeue();
        }
        buffer[rear] = value;
        rear = (rear + 1) % buffer.length;
        size++;
    }

    public int dequeue() {
        if (isEmpty()) {
            throw new RuntimeException("Queue is empty");
        }
        int value = buffer[front];
        front = (front + 1) % buffer.length;
        size--;
        return value;
    }
}

上述代码中，CircularQueue 类实现了循环队列的基本操作。在测试方法中，使用 JUnit 进行测试，确保循环队列的实现正确，并覆盖了各种情况，包括正常情况、环绕情况和覆盖情况。