test: Add test for negative stream drain counter

test/simple/test-stream2-readable-legacy-drain.js

@@ -0,0 +1,75 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+var assert = require('assert');
+
+var Stream = require('stream');
+var Readable = Stream.Readable;
+
+var r = new Readable();
+var N = 256;
+var reads = 0;
+r._read = function(n, cb) {
+  return cb(null, ++reads === N ? null : new Buffer(1));
+};
+
+var rended = false;
+r.on('end', function() {
+  rended = true;
+});
+
+var w = new Stream();
+w.writable = true;
+var writes = 0;
+var buffered = 0;
+w.write = function(c) {
+  writes += c.length;
+  buffered += c.length;
+  process.nextTick(drain);
+  return false;
+};
+
+function drain() {
+  assert(buffered <= 2);
+  buffered = 0;
+  w.emit('drain');
+}
+
+
+var wended = false;
+w.end = function() {
+  wended = true;
+};
+
+// Just for kicks, let's mess with the drain count.
+// This verifies that even if it gets negative in the
+// pipe() cleanup function, we'll still function properly.
+r.on('readable', function() {
+  w.emit('drain');
+});
+
+r.pipe(w);
+process.on('exit', function() {
+  assert(rended);
+  assert(wended);
+  console.error('ok');
+});