a install WITHOUT tests appears to be needed before the tests can be run

I am just starting to set up a build of Syncope from source.

I forked the Github and set up a new Centos 7

Maven home: /opt/apache-maven-3.6.2
Java version: 12.0.2, vendor: Oracle Corporation, runtime: /opt/jdk-12.0.2
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "3.10.0-957.27.2.el7.x86_64", arch: "amd64", family: "unix"

I did the

mvn clean install

But that errored out in a test that needed the Core before the core had been build.

I found that doing a mvn -PskipTests,all then a
mvn -PskipTests,install

completes and then the

mvn clean install works fine.

This is my first day in Maven so I am not sure what is going on.