test: add tests for stream3 buffering using cork

adds 2 new tests for streams3 cork behavior, cork then uncork and cork then end
PR-URL: #6493
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: alexjeffburke

test/parallel/test-stream3-cork-end.js

@@ -0,0 +1,91 @@
+'use strict';
+require('../common');
+constassert=require('assert');
+conststream=require('stream');
+constWritable=stream.Writable;
+
+// Test the buffering behaviour of Writable streams.
+//
+// The call to cork() triggers storing chunks which are flushed
+// on calling end() and the stream subsequently ended.
+//
+// node version target: 0.12
+
+constexpectedChunks=['please','buffer','me','kindly'];
+varinputChunks=expectedChunks.slice(0);
+varseenChunks=[];
+varseenEnd=false;
+
+varw=newWritable();
+// lets arrange to store the chunks
+w._write=function(chunk,encoding,cb){
+// stream end event is not seen before the last write
+assert.ok(!seenEnd);
+// default encoding given none was specified
+assert.equal(encoding,'buffer');
+
+seenChunks.push(chunk);
+cb();
+};
+// lets record the stream end event
+w.on('finish',()=>{
+seenEnd=true;
+});
+
+functionwriteChunks(remainingChunks,callback){
+varwriteChunk=remainingChunks.shift();
+varwriteState;
+
+if(writeChunk){
+setImmediate(()=>{
+writeState=w.write(writeChunk);
+// we were not told to stop writing
+assert.ok(writeState);
+
+writeChunks(remainingChunks,callback);
+});
+}else{
+callback();
+}
+}
+
+// do an initial write
+w.write('stuff');
+// the write was immediate
+assert.equal(seenChunks.length,1);
+// reset the seen chunks
+seenChunks=[];
+
+// trigger stream buffering
+w.cork();
+
+// write the bufferedChunks
+writeChunks(inputChunks,()=>{
+// should not have seen anything yet
+assert.equal(seenChunks.length,0);
+
+// trigger flush and ending the stream
+w.end();
+
+// stream should not ended in current tick
+assert.ok(!seenEnd);
+
+// buffered bytes should be seen in current tick
+assert.equal(seenChunks.length,4);
+
+// did the chunks match
+for(vari=0,l=expectedChunks.length;i<l;i++){
+varseen=seenChunks[i];
+// there was a chunk
+assert.ok(seen);
+
+varexpected=newBuffer(expectedChunks[i]);
+// it was what we expected
+assert.ok(seen.equals(expected));
+}
+
+setImmediate(()=>{
+// stream should have ended in next tick
+assert.ok(seenEnd);
+});
+});

test/parallel/test-stream3-cork-uncork.js

@@ -0,0 +1,86 @@
+'use strict';
+require('../common');
+constassert=require('assert');
+conststream=require('stream');
+constWritable=stream.Writable;
+
+// Test the buffering behaviour of Writable streams.
+//
+// The call to cork() triggers storing chunks which are flushed
+// on calling uncork() in the same tick.
+//
+// node version target: 0.12
+
+constexpectedChunks=['please','buffer','me','kindly'];
+varinputChunks=expectedChunks.slice(0);
+varseenChunks=[];
+varseenEnd=false;
+
+varw=newWritable();
+// lets arrange to store the chunks
+w._write=function(chunk,encoding,cb){
+// default encoding given none was specified
+assert.equal(encoding,'buffer');
+
+seenChunks.push(chunk);
+cb();
+};
+// lets record the stream end event
+w.on('finish',()=>{
+seenEnd=true;
+});
+
+functionwriteChunks(remainingChunks,callback){
+varwriteChunk=remainingChunks.shift();
+varwriteState;
+
+if(writeChunk){
+setImmediate(()=>{
+writeState=w.write(writeChunk);
+// we were not told to stop writing
+assert.ok(writeState);
+
+writeChunks(remainingChunks,callback);
+});
+}else{
+callback();
+}
+}
+
+// do an initial write
+w.write('stuff');
+// the write was immediate
+assert.equal(seenChunks.length,1);
+// reset the chunks seen so far
+seenChunks=[];
+
+// trigger stream buffering
+w.cork();
+
+// write the bufferedChunks
+writeChunks(inputChunks,()=>{
+// should not have seen anything yet
+assert.equal(seenChunks.length,0);
+
+// trigger writing out the buffer
+w.uncork();
+
+// buffered bytes shoud be seen in current tick
+assert.equal(seenChunks.length,4);
+
+// did the chunks match
+for(vari=0,l=expectedChunks.length;i<l;i++){
+varseen=seenChunks[i];
+// there was a chunk
+assert.ok(seen);
+
+varexpected=newBuffer(expectedChunks[i]);
+// it was what we expected
+assert.ok(seen.equals(expected));
+}
+
+setImmediate(()=>{
+// the stream should not have been ended
+assert.ok(!seenEnd);
+});
+});