}

    @Test
    void testConstructor() {
        assertNotNull(channelManager);
        assertFalse(channelManager.isUseMultiChannel());
        assertEquals(0, channelManager.getChannels().size());
        assertNotNull(channelManager.getLoadBalancer());
    }

    @Test
    void testInitializationWithoutMultiChannelSupport() throws IOException {

        public ChannelGroup(String sessionId) {
            this.sessionId = sessionId;
        }

        public String getSessionId() {
            return sessionId;
        }

        public List<ChannelInfo> getChannels() {
            return new ArrayList<>(channels);
        }

        public void addChannel(ChannelInfo channel) {
            channels.add(channel);
            if (primaryChannel == null) {

    }

    @Test
    void testMultiChannelInitialization() throws Exception {
        // Test that ChannelManager initializes properly
        assertNotNull(channelManager);
        assertNotNull(channelManager.getChannels());
        // Note: isUseMultiChannel() checks if actual multi-channel is negotiated with server
        // In mock environment, this will be false until we mock successful negotiation

        return loadBalancer;
    }

    /**
     * Get all channels
     *
     * @return collection of all channels
     */
    public Collection<ChannelInfo> getChannels() {
        return channels.values();
    }

    /**
     * Get healthy channels only
     *
     * @return collection of healthy channels
     */

    assertEquals(ChannelState.FAILED, channel.getState());
    
    // Verify recovery attempted
    Thread.sleep(2000);
    assertTrue(channel.getState() == ChannelState.ESTABLISHED 
        || manager.getChannels().isEmpty());
}
```

### 7.2 Integration Tests
```java
@Test
public void testMultiChannelThroughput() throws Exception {
    // Requires multi-NIC test environment

        assertArgumentNotNull("file", file);

        final FileInputStream is = InputStreamUtil.create(file);
        try {
            final FileChannel channel = is.getChannel();
            final long fileSize = ChannelUtil.size(channel);

            if (fileSize > maxSize) {

     * @return the number of bytes copied
     */
    protected static int copyInternal(final FileInputStream in, final FileOutputStream out) {
        final FileChannel ic = in.getChannel();
        final FileChannel oc = out.getChannel();
        return (int) ChannelUtil.transfer(ic, oc);
    }

    /**
     * Copies the contents of a reader to a writer.
     * <p>