diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index d96c7da66d..7220252fea 100644
--- a/lib/_stream_writable.js
+++ b/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;
diff --git a/test/parallel/test-stream-writableState-ending.js b/test/parallel/test-stream-writableState-ending.js
new file mode 100644
index 0000000000..1e0b0bf77f
--- /dev/null
+++ b/test/parallel/test-stream-writableState-ending.js
@@ -0,0 +1,34 @@
+'use strict';
+
+require('../common');
+
+const assert = require('assert');
+const stream = require('stream');
+
+const writable = new stream.Writable();
+
+function testStates(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);