test: writable stream ending state

Add a test for _writableState.ending, when ending becomes true, but the stream is not finished/ended yet. PR-URL: #8707 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Matteo Collina <[email protected]> Related: #8686

Author: Italo A. Casas

lib/_stream_writable.js

@@ -43,6 +43,7 @@ function WritableState(options, stream){
 // cast to ints.
 this.highWaterMark=~~this.highWaterMark;
 
+// drain event flag.
 this.needDrain=false;
 // at the start of calling end()
 this.ending=false;

test/parallel/test-stream-writableState-ending.js

@@ -0,0 +1,34 @@
+'use strict';
+
+require('../common');
+
+constassert=require('assert');
+conststream=require('stream');
+
+constwritable=newstream.Writable();
+
+functiontestStates(ending,finished,ended){
+assert.strictEqual(writable._writableState.ending,ending);
+assert.strictEqual(writable._writableState.finished,finished);
+assert.strictEqual(writable._writableState.ended,ended);
+}
+
+writable._write=(chunk,encoding,cb)=>{
+// ending, finished, ended start in false.
+testStates(false,false,false);
+cb();
+};
+
+writable.on('finish',()=>{
+// ending, finished, ended = true.
+testStates(true,true,true);
+});
+
+writable.end('testing function end()',()=>{
+// ending, finished, ended = true.
+testStates(true,true,true);
+});
+
+// ending, ended = true.
+// finished = false.
+testStates(true,false,true);