Stuck attempting to run/develop a manual unit test

[Craig Cavanaugh]

I am trying to create a manual unit test for RFR: 8129123 and I'm using the
existing ButtonMnemonicPositionTest.java as a template to make sure
everything is working correctly.

I'm using an Ubuntu 18.04.4 build environment using the default 11.0.6
openjdk.
openjfx is successfully compiling and passing tests following the wiki
instructions

I'm able to compile ButtonMnemonicPositionTest successfully as shown below.
javac -classpath  .:/home/craig/IdeaProjects/jfx/build/sdk/lib/*
ButtonMnemonicPositionTest.java

But attempts to run are failing despite a successful compile:
java -classpath  .:/home/craig/IdeaProjects/jfx/build/sdk/lib/*
ButtonMnemonicPositionTest
Error: JavaFX runtime components are missing, and are required to run this
application

I've also tried running using the modular-sdk after a Gradle build and no
luck either after finding a recommendation on the list that the module
approach should be used for testing.

java --module-path /home/craig/IdeaProjects/jfx/build/modular-sdk/modules
--add-modules=javafx.controls ButtonMnemonicPositionTest
Error occurred during initialization of boot layer
java.lang.module.FindException: Module javafx.controls not found

I've been search through the list archive and haven't found a solution.
I'm sure I'm doing something wrong.

Some help please!

Regards,
Craig