Fix process not exiting calling .close() right after watching. (#600)

* Fix process not exiting calling .close() right after watching.

* Attempt to fix failing tests on linux.

* Fix tests on windows.

index.js

@@ -624,7 +624,7 @@ FSWatcher.prototype.add = function(paths, _origAdd, _internal) {
       }.bind(this));
     }.bind(this), function(error, results) {
       results.forEach(function(item) {
-        if (!item) return;
+        if (!item || this.closed) return;
         this.add(sysPath.dirname(item), sysPath.basename(_origAdd || item));
       }, this);
     }.bind(this));

lib/fsevents-handler.js

@@ -374,6 +374,7 @@ function(path, transform, forceAdd, priorDepth) {
 
   if (this.options.persistent && forceAdd !== true) {
     var initWatch = function(error, realPath) {
+      if (this.closed) return;
       var closer = this._watchWithFsEvents(
         wh.watchPath,
         sysPath.resolve(realPath || wh.watchPath),

test.js

@@ -8,6 +8,7 @@ var sinon = require('sinon');
 var rimraf = require('rimraf');
 var fs = require('graceful-fs');
 var sysPath = require('path');
+var cp = require('child_process');
 chai.use(require('sinon-chai'));
 var os = process.platform;
 
@@ -1820,6 +1821,22 @@ function runTests(baseopts) {
         });
       });
     });
+    it('should not prevent the process from exiting', function(done) {
+        var scriptFile = getFixturePath('script.js');
+        var scriptContent = '\
+        var chokidar = require("' + __dirname.replace(/\\/g, '\\\\') + '");\n\
+        var watcher = chokidar.watch("' + scriptFile.replace(/\\/g, '\\\\') + '");\n\
+        watcher.close();\n\
+        process.stdout.write("closed");\n';
+        fs.writeFile(scriptFile, scriptContent, function (err) {
+            if (err) throw err;
+            cp.exec('node ' + scriptFile, function (err, stdout) {
+                if (err) throw err;
+                expect(stdout.toString()).to.equal('closed');
+                done();
+            });
+        });
+    });
   });
   describe('env variable option override', function() {
     describe('CHOKIDAR_USEPOLLING', function() {