Question: I am using the Email-ext plugin on Jenkins, and the default Jelly script ${JELLY\_SCRIPT,template="html"}.

The template apparently outputs all unit tests in the email, not just the ones that have failed and made the build unstable. This is in itself a strange design decision since the important content gets lost, but is there an easy way to just output the failed tests in the email? I suppose I need to edit the default Jelly script template somewhere? Thanks!

Answer: 
`${JELLY_SCRIPT,template="html"}` in this script `html` refers to the file `html.jelly`. In Hudson this file is located in the path, `HUDSON_HOME/plugins/email-ext/WEB-INF/classes/hudson/plugins/emailext/templates`. You can create your own jelly file, say abc.jelly and use the script as `${JELLY_SCRIPT,template="abc"}`

However, in Jenkin this jelly templates have been bundled to the jar `email-ext.jar` which is located in `Jenkin_Home/plugins/email-ext/WEB-INF/lib`. Open this Jar and update/create templates in the location `/plugins/emailext/templates/` as per your requirement.
There is an excellent example for how it is done using Jelly script in:
<https://github.com/jenkinsci/email-ext-plugin/blob/master/src/main/resources/hudson/plugins/emailext/templates/html-with-health-and-console.jelly>
-> Search for "JUnit TEMPLATE".

But more specifically it is done using

```
packageResult.getFailedTests()

```