Loading .xacro into .xacro does not have a visible effect - ros

Question

I'm searching for an answer to why I can not see my second .xacro file that I'm including in my first one. - Here's my MWE:
I'm succefully loading a .xacro file and seeing it in Rviz by launching following launch file:
<launch>
<param name="robot_description" textfile="$(find my_package)/urdf/test.urdf.xacro" />
<node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher"/>
<node pkg="rviz" type="rviz" name="rviz" />
</launch>
My test.urdf.xacro file has following content:
<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="test">
<xacro:include filename="$(find my_package)/urdf/glass.urdf.xacro" />
<link name="base_link">
<visual>
<origin xyz="0 0 1" rpy="0 0 0" />
<geometry>
<box size="0.1 0.1 1" />
</geometry>
<material name="blue1">
<color rgba="0.28 0.52 0.93 1" />
</material>
</visual>
</link>
</robot>
My second .xacro file "glass.urdf.xacro" has following content:
<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="test2">
<link name="base_link2">
<visual>
<origin xyz="0 1 0" rpy="0 0 0" />
<geometry>
<box size="0.1 0.1 1" />
</geometry>
<material name="blue2">
<color rgba="0.28 0.1 0.93 1" />
</material>
</visual>
</link>
</robot>
The two files work seperatly but the xacro:include doesn't seem to be doing anything...Any ideas what I should do to use it succesfully?
How can I check what my resulting urdf file looks like?

Answer 1

Figured this out. You need to use xacro to parse the robot_description in the launch file. Like this:
<param name="robot_description" command="xacro '$(find my_package)/urdf/test.urdf.xacro"' />
Otherwise, xacro isn't used to parse your test.urdf.xacro file and the included files are not processed.