jenkins email-ext plugin Email Template Testing

I started using the email-ext plugin. I added the plugin as "post build" step to a configuration. A job was built and now I want to send an test email. 

Here is what I did:
- Create the folder $JENKINS_HOME\email-templates, where JENKINS_HOME is D:\jenkins
- Download the groovy-html.template and copy it to D:\jenkins\email-templates

- On the "Email Template Testing"-page I inserted the filename: "groovy-html.template"

others email template:

https://github.com/jenkinsci/email-ext-plugin/tree/master/src/main/resources/hudson/plugins/emailext/templates