Using JDK HttpServer in a JUnit test

URLTest.java

/* 
* Copyright © 2017 Mike Duigou. 
* Public Domain. No Rights Reserved.
*/

public class URLTest {

    private static final Logger LOGGER = Logger.getLogger(URLTest.class.getSimpleName());
   
    private static final int TEST_FILE_SIZE = 1 << 20;

    private static final String SOURCE_FILE_NAME = "test.file";

    private static final String SOURCE_FILE_PATH = "/" + SOURCE_FILE_NAME;

    private static final Random RANDOM = DEBUG ? new Random(0) : new Random();

    private static final byte[] TEST_DATA = new byte[TEST_FILE_SIZE];

    static {
        RANDOM.nextBytes(TEST_DATA);
    }

    private static URL source;

    private static HttpServer server;

    @BeforeClass
    public static void setUp() throws Exception {
        InetSocketAddress address = new InetSocketAddress(InetAddress.getLoopbackAddress(), 0);
        server = HttpServer.create(address, 40);
        server.setExecutor(ForkJoinPool.commonPool());
        HttpContext context = server.createContext(SOURCE_FILE_PATH, (HttpExchange he) -> {
            String path = he.getRequestURI().getPath();
            if (!"GET".equals(he.getRequestMethod()) || !SOURCE_FILE_PATH.equals(path)) {
                he.sendResponseHeaders(404, 0);
            } else {
                Headers headers = he.getResponseHeaders();
                headers.add("Content-Type", "application/octet-stream");
                headers.add("Content-Disposition", "attachment; filename=\"" + SOURCE_FILE_PATH + "\"");
                he.sendResponseHeaders(200, TEST_FILE_SIZE);
                try (OutputStream out = he.getResponseBody()) {
                    out.write(TEST_DATA);
                }
            }
        });
        server.start();
        InetSocketAddress boundAddresss = server.getAddress();
        LOGGER.inform("server", server, "address=" + server.getAddress());
        source = new URL("http", boundAddresss.getAddress().getHostAddress(), boundAddresss.getPort(), SOURCE_FILE_PATH);
    }

    @AfterClass
    public static void tearDown() throws Exception {
        server.stop(3);
        LOGGER.inform("server shutdown");
    }   

    /**
     * Test of getInputStream method, of class.
     */
    @Test
    public void testGetInputStream() throws Exception {
        try (InputStream input = source.openConnection().getInputStream()) {
            assertNotNull(input);
            ByteArrayOutputStream bos = new ByteArrayOutputStream(TEST_FILE_SIZE);
            Streams.copy(input, bos);
            assertArrayEquals(TEST_DATA, bos.toByteArray());
        }
    }
}