First, it should be noted in the comments that this test is not applicable to .dmg

Test both --file-associations and --install-dir parameters
artifact_name: InstallDirTest-1.0.dmg and InstallDirTest-1.0.pkg

Steps to Reproduce:
(1) Run InstallDirTest package
(2) Open Finder and navigate to Applications

Expected Result:
packaged is installed in: /Applications/TestVendor/InstallDirTest

Actual Result:
packaged is installed in: /Applications/InstallDirTest

either the jpackage args are not honored or this test is applicable to Mac