--- /dev/null
+// 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 constants = require('constants');
+var fs = require('fs');
+
+var O_APPEND = constants.O_APPEND || 0;
+var O_CREAT = constants.O_CREAT || 0;
+var O_DIRECTORY = constants.O_DIRECTORY || 0;
+var O_EXCL = constants.O_EXCL || 0;
+var O_NOCTTY = constants.O_NOCTTY || 0;
+var O_NOFOLLOW = constants.O_NOFOLLOW || 0;
+var O_RDONLY = constants.O_RDONLY || 0;
+var O_RDWR = constants.O_RDWR || 0;
+var O_SYMLINK = constants.O_SYMLINK || 0;
+var O_SYNC = constants.O_SYNC || 0;
+var O_TRUNC = constants.O_TRUNC || 0;
+var O_WRONLY = constants.O_WRONLY || 0;
+
+assert.equal(fs._stringToFlags('r'), O_RDONLY);
+assert.equal(fs._stringToFlags('r+'), O_RDWR);
+assert.equal(fs._stringToFlags('w'), O_TRUNC|O_CREAT|O_WRONLY);
+assert.equal(fs._stringToFlags('w+'), O_TRUNC|O_CREAT|O_RDWR);
+assert.equal(fs._stringToFlags('a'), O_APPEND|O_CREAT|O_WRONLY);
+assert.equal(fs._stringToFlags('a+'), O_APPEND|O_CREAT|O_RDWR);
+
+'+ +a +r +w rw wa war raw r++ a++ w++'.split(' ').forEach(function(flags) {
+ assert.throws(function() { fs._stringToFlags(flags); });
+});