To run tests, make sure to include the following tests package in your build:
//src/ui/bin/root_presenter:tests

After building, presenter tests can be run as follows:
fx test run "fuchsia-pkg://fuchsia.com/root_presenter_tests#meta/focus_dispatcher_unittests.cm"
fx test run "fuchsia-pkg://fuchsia.com/root_presenter_tests#meta/root_presenter_unittests.cm"