Problem: Test Project needlessly builds its target application
Currently Project2 requires a full build before executing tests - simply because the test tools are integrated into Project1.
Also, Project2 is a PHP Composer project, so the test tool binaries are NOT present after pulling source from SCM. Composer install is required before those binaries are available. With build times of roughly 50m & test times of less than 10m - this feels like insanity.
Solution
The project(Projec1) build & tests(Project2) need to be segregated so Project1 needs to pass its ${WORKSPACE} value to the triggered 'downstream' project. To do so use 'Predefined parameters':
Projec1 - Upstream - Parameters
BuildDeployWkspc=${WORKSPACE}
BuildDeployBuildNum=${BUILD_NUMBER}
Project2 - DownStream - Variables
$BuildDeployWkspc
$BuildDeployBuildNum