Netty use Embeddedchannel for unit testing

Netty use Embeddedchannel for unit testing
For unit testing of Netty Channelhandler, Netty provides embeddedchannel embedded channel to complete this process, which is used primarily to test the legality of inbound and outbound process of data; The channel provides the following common APIs:

Writeinbound	Write a inbound message to Embeddedchannel. Returns true if the data can be read from Embeddedchannel through Readinbound ();
Readinbound	Read from Embeddedchannel to inbound messages. Any return traversal of the entire channelpipeline. If the read is not yet ready, this method returns null;
Writeoutbound	Write an outbound message to Embeddedchannel. Returns true if the data can be read from Embeddedchannel through Readoutbound ();
Readoutbound	Read the outbound message from the Embeddedchannel. Any return traversal of the entire channelpipeline. If the read is not yet ready, this method returns null;
Finish	If the data can be read from the inbound or outbound, the tag Embeddedchannel is completed and returned. This will also invoke the Embeddedchannel shutdown method;

Full API See: http://netty.io/4.1/api/io/netty/channel/embedded/EmbeddedChannel.html

The following illustration shows how Channelpipeline uses Embeddedchannel:

The complete code address for the following instance: Https://gitee.com/assad/netty-test-sample/tree/master/netty-test-sample/src/main/java/junitSample
Inbound Processor TestThe following tests an inbound decoder fixedlengthframedecoder; Fixedlengthframedecoder

Decoder for testing, separating the frames read to a fixed length

public class Fixedlengthframedecoder extends Bytetomessagedecoder {

private final int framelength; Frame length

Public fixedlengthframedecoder (int framelength) {

This.framelength = Framelength;

  }

@Override

protected void decode (Channelhandlercontext ctx, bytebuf in, list<object> out) throws Exception {

Frame segmentation

while (In.readablebytes () >= framelength)

Out.add (In.readbytes (framelength));

  }

}

Test code:

@Test

public void Testfixedframedecoder () {

Embeddedchannel channel = new Embeddedchannel (new Fixedlengthframedecoder (4));

Test Inbound writes

Bytebuf buf = Unpooled.buffer ();

for (int i = 0; i < i++)

Buf.writebyte (i);

Bytebuf in = Buf.duplicate ();

The inbound writes 3 bytes, at which point Decoder caches the data and does not forward the data to the next Channelhandler

Assertfalse (Channel.writeinbound (In.readbytes (3)));

The inbound writes 7 bytes, plus the 3 bytes previously written, Decoder forwards the first 8 bytes, divides into 2 groups to forward to the next Channelhandler, and the remaining 2 bytes are still cached

Asserttrue (Channel.writeinbound (In.readbytes (7)));

Asserttrue (Channel.finish ()); Send an end signal to the channel

Test inbound Reads

From the above write process can be estimated, the first 2 times can be read to the value, the 3rd time read to a null value

BYTEBUF read = Channel.readinbound ();

Assertequals (Read,buf.readslice (4));

Read.release ();

Read = Channel.readinbound ();

Assertequals (Read,buf.readslice (4));

Read.release ();

Read = Channel.readinbound ();

Assertnull (read);

  }

Outbound Processor TestingThe following tests an inbound encoder fixedlengthframedecoder;
Fixedlengthframedecoder

Encoder for the test, the Integer of the read is absolute

public class Absintegerencoder extends Messagetomessageencoder<bytebuf> {

@Override

protected void Encode (Channelhandlercontext ctx, bytebuf in, list<object> out) throws Exception {

while (In.readablebytes () >= 4) {

int i = Math.Abs (In.readint ());

Out.add (i);

  }

  }

}

Test code:

@Test

public void Testabsintegerencoder () {

Embeddedchannel channel = new Embeddedchannel (new Absintegerencoder ());

To test outbound writes

Bytebuf buf = Unpooled.buffer ();

for (int i = 0; i < i++)

Buf.writeint (i *-1);

Asserttrue (Channel.writeoutbound (BUF));

Asserttrue (Channel.finish ());

Testing outbound Reads

for (int i = 0; i < i++)

Assertequals ((Integer) i,channel.readoutbound ());

Assertnull (Channel.readoutbound ());

  }

Exception capture TestThe processor that throws the exception, Fixedlengthframedecoder

public class Fixedlengthframedecoder extends Bytetomessagedecoder {

private final int framelength; Frame length

private final int maxframesize; Maximum frame length

Public fixedlengthframedecoder (int framelength) {

This.framelength = Framelength;

This.maxframesize = 256;

  }

Public Fixedlengthframedecoder (int framelength, int maxframesize) {

This.framelength = Framelength;

This.maxframesize = MaxFrameSize;

  }

@Override

protected void decode (Channelhandlercontext ctx, bytebuf in, list<object> out) throws Exception {