Add 'test' button to SMTP UI to test connections.

frontend/src/views/settings/smtp.vue

@@ -150,6 +150,13 @@
             </div>
           </div>
         </div><!-- second container column -->
+        <div class="columns">
+          <div class="column has-text-right">
+            <b-button class="is-primary" @click.prevent="testConnection(item)">
+              {{ $t('settings.smtp.testConnection') }}
+            </b-button>
+          </div>
+        </div>
       </div><!-- block -->
     </div><!-- mail-servers -->
 
@@ -211,6 +218,10 @@ export default Vue.extend({
       s.showHeaders = true;
       this.data.smtp.splice(i, 1, s);
     },
+
+    testConnection(c) {
+      alert(c);
+    },
   },
 });
 </script>

i18n/en.json

@@ -453,6 +453,7 @@
     "settings.smtp.retries": "Retries",
     "settings.smtp.retriesHelp": "Number of times to retry when a message fails.",
     "settings.smtp.setCustomHeaders": "Set custom headers",
+    "settings.smtp.testConnection": "Test connection",
     "settings.title": "Settings",
     "settings.updateAvailable": "A new update {version} is available.",
     "subscribers.advancedQuery": "Advanced",