### Question:
CompressUtil { public static boolean isCompressData(byte[] bytes) { if (bytes != null && bytes.length > 2) { int header = ((bytes[0] & 0xff)) | (bytes[1] & 0xff) << 8; return GZIPInputStream.GZIP_MAGIC == header; } return false; }  static byte[] compress(final byte[] src); static byte[] uncompress(final byte[] src); static boolean isCompressData(byte[] bytes);  }### Answer:
@Test public void testIsCompressData() { Assertions.assertFalse(CompressUtil.isCompressData(null)); Assertions.assertFalse(CompressUtil.isCompressData(new byte[0])); Assertions.assertFalse(CompressUtil.isCompressData(new byte[]{31, 11})); Assertions.assertFalse( CompressUtil.isCompressData(new byte[]{31, 11, 0})); Assertions.assertTrue( CompressUtil.isCompressData(new byte[]{31, -117, 0})); }