🆙 update(e2e): record screenshots for e2e test failures

Author: kazupon

.gitignore

@@ -2,7 +2,8 @@ lib
 coverage
 dist/*.gz
 docs/_book
-test/e2e/report/
+test/e2e/report
+test/e2e/screenshots
 node_modules
 .DS_Store
 *.log

config/nightwatch.conf.js

@@ -19,7 +19,13 @@ module.exports = {
     default: {
       selenium_port: 4444,
       selenium_host: 'localhost',
-      silent: true
+      silent: true,
+      screenshots: {
+        enabled: true,
+        on_failure: true,
+        on_error: false,
+        path: 'test/e2e/screenshots'
+      }
     },
 
     chrome: {