fix(runner): gracefully shutdown browsers after test

Author: hankduan

lib/runner.js

@@ -200,6 +200,14 @@ Runner.prototype.run = function() {
 
   this.setTestPreparer(this.config_.onPrepare);
 
+  var gracefulShutdown = function(driver) {
+    return driver.getSession().then(function(session_) {
+      if (session_) {
+        return driver.quit();
+      }
+    });
+  };
+
   // 1) Setup environment
   //noinspection JSValidateTypes
   return this.driverprovider_.setupEnv().then(function() {
@@ -254,6 +262,8 @@ Runner.prototype.run = function() {
     var passed = testResult.failedCount === 0;
     var exitCode = passed ? 0 : 1;
     return self.exit_(exitCode);
+  }).fin(function() {
+   return gracefulShutdown(driver);
   });
 };