Download latest nightly build
https://download.eclipse.org/ee4j/jakartaee-tck/8.0.1/nightly/eltck-3.0_latest.zip
Extract to EL_TCK_HOME
Edit $EL_TCK_HOME/bin/ts.jte
You'll need to set the following properties (adjust the paths for your environment)
el.classes=/home/mark/repos/asf-public/tomcat/trunk/output/build/lib/el-api.jar:/home/mark/repos/asf-public/tomcat/trunk/output/build/lib/jasper-el.jar
variable.mapper=org.apache.el.lang.VariableMapperImpl
Run ant gui
Accept the defaults and then run the tests