added information regarding test messages to README.md

README.md

@@ -11,7 +11,7 @@ The file is structured by directives controlling the various aspects of the prog
 ### service
 
 In this directive you define the notification service to use. VE.Direct-notify is tested and proofed working with the OpenSource notification service ntfy.  
-The topic URL to use is derived from the parameters url and topic combined. the parameter url is to be given *without a trailing slash*.  
+The topic URL to use is derived from the parameters url and topic combined. the parameter url is to be given **without a trailing slash**.  
 VE.Direct-notify supports conneting to notification services with and without authentication. Authentication can be by Username/Password or Authentication Token.  
   
 example without authentication:
@@ -23,7 +23,7 @@ example without authentication:
 ```
 
 
-examaple with authentication using a username and password:  
+example with authentication using a username and password:  
 ```
 "service": {
     "url": "https://ntfy.yourdomain.com",
@@ -117,6 +117,16 @@ Once tested successfully, it can be set up as a cron-job:
 In the cron table fill in a line like this:
 `0 * * * * php /path/to/your/VE.Direct-ntfy-instance/worker.php`
 
+### send test message to notification server
+
+VE.Direct-notify is able to send test messages to the notification serivce to check whether it can use the configured service properly.  
+To send a test message the following command can be used on the command line:  
+```
+$ cd /path/to/your/VE.Direct-ntfy-instance
+$ php worker.php test <notificationType>
+```
+<notificationType> shall be replaced by either warning or error.
+
 ## Troubleshooting
 
 ## Contributing