### Question:
X25Channel extends BaseChannel { protected void connect (Socket socket) throws IOException { super.connect (socket); reader = new BufferedReader (new InputStreamReader (serverIn)); } X25Channel();  X25Channel(String host, int port, ISOPackager p);  X25Channel(ISOPackager p);  X25Channel(ISOPackager p, ServerSocket serverSocket); void disconnect(); void setHeader(byte[] header); void setHeader(String header); byte[] getHeader();  }### Answer:
@Test public void testConnectThrowsNullPointerException() throws Throwable { X25Channel x25Channel = new X25Channel("testX25ChannelHost", 100, new ISO87APackagerBBitmap()); x25Channel.setTimeout(1); Socket socket = new Socket(Proxy.NO_PROXY); try { x25Channel.connect(socket); fail("Expected NullPointerException to be thrown"); } catch (NullPointerException ex) { if (isJavaVersionAtMost(JAVA_14)) { assertNull(ex.getMessage(), "ex.getMessage()"); } else { assertEquals("Cannot invoke \"java.net.InetAddress.getHostAddress()\" because the return value of \"java.net.Socket.getInetAddress()\" is null", ex.getMessage(), "ex.getMessage()"); } assertNull(x25Channel.reader, "x25Channel.reader"); assertEquals("org.jpos.iso.channel.X25Channel", x25Channel.getOriginalRealm(), "x25Channel.getOriginalRealm()"); assertEquals(3, x25Channel.getCounters().length, "x25Channel.getCounters().length"); assertNull(x25Channel.getRealm(), "x25Channel.getRealm()"); assertSame(socket, x25Channel.getSocket(), "x25Channel.getSocket()"); assertFalse(x25Channel.isConnected(), "x25Channel.isConnected()"); assertNull(x25Channel.getLogger(), "x25Channel.getLogger()"); assertNull(socket.getChannel(), "socket.getChannel()"); } }
@Test public void testConnectThrowsSocketException() throws Throwable { Socket socket = new Socket(); X25Channel x25Channel = new X25Channel(); socket.close(); try { x25Channel.connect(socket); fail("Expected SocketException to be thrown"); } catch (SocketException ex) { assertEquals(SocketException.class, ex.getClass(), "ex.getClass()"); assertNull(x25Channel.reader, "x25Channel.reader"); assertEquals("org.jpos.iso.channel.X25Channel", x25Channel.getOriginalRealm(), "x25Channel.getOriginalRealm()"); assertEquals(3, x25Channel.getCounters().length, "x25Channel.getCounters().length"); assertNull(x25Channel.getRealm(), "x25Channel.getRealm()"); assertSame(socket, x25Channel.getSocket(), "x25Channel.getSocket()"); assertFalse(x25Channel.isConnected(), "x25Channel.isConnected()"); assertNull(x25Channel.getLogger(), "x25Channel.getLogger()"); assertNull(socket.getChannel(), "socket.getChannel()"); } }