How to create a working email filter?

What should happen when I test a filter?

I am trying to create a filter that will redirect mail from a specific address and with a certain phrase in the subject line to another address.
Following How to Configure Mail Filters - cPanel Knowledge Base - cPanel Documentation
I have created this rule

rules
To equals xxx@yyy.co.uk
subject contains XXX - CP
action
redirect to xxx:hotmail.co.uk
​

I copied in a sample email with To: xxx@yyy.co.uk and Subject: MAM - CP 2017-12-12 into the test box but when I clicked the test button nothing appeared in the Filter Trace.

To test it further I left the sample email in the test box ie

To: test@localhost
From: test@localhost
Subject: test

This is a test message.​

and made another simple rule

rule
subject contains test
action
redirect to xxx:hotmail.co.uk​

but still nothing happened when I clicked test.

What should I expect to happen and how can I ensure the filter is working correctly?

 

Just a bit more info.

I have finally got a filter to actually work and can test it by really redirecting an email to myself based upon the To: and Subject:

However if I paste that same email into the test box and click 'Test', I still get nothing happening except a blank progress bar with the heading 'Filter Trace'.

So I still don't know how to test the filters without really sending dummy test emails to possibly lots of unsuspecting recipients.