----------
Foo_ROOT      :
ENV{Foo_ROOT} :

find_package\(Foo\)
FOO_TEST_FILE_FOO :FOO_TEST_FILE_FOO-NOTFOUND
FOO_TEST_FILE_ZOT :FOO_TEST_FILE_ZOT-NOTFOUND
FOO_TEST_PATH_FOO :FOO_TEST_PATH_FOO-NOTFOUND
FOO_TEST_PATH_ZOT :FOO_TEST_PATH_ZOT-NOTFOUND
FOO_TEST_PROG_FOO :FOO_TEST_PROG_FOO-NOTFOUND

----------
Foo_ROOT      :<base>/foo/cmake_root
ENV{Foo_ROOT} :

find_package\(Foo\)
FOO_TEST_FILE_FOO :<base>/foo/cmake_root/include/foo.h
FOO_TEST_FILE_ZOT :<base>/foo/cmake_root/include/zot/zot.h
FOO_TEST_PATH_FOO :<base>/foo/cmake_root/include
FOO_TEST_PATH_ZOT :<base>/foo/cmake_root/include/zot
FOO_TEST_PROG_FOO :<base>/foo/cmake_root/bin/foo.exe

----------
Foo_ROOT      :
ENV{Foo_ROOT} :<base>/foo/env_root

find_package\(Foo\)
FOO_TEST_FILE_FOO :<base>/foo/env_root/include/foo.h
FOO_TEST_FILE_ZOT :<base>/foo/env_root/include/zot/zot.h
FOO_TEST_PATH_FOO :<base>/foo/env_root/include
FOO_TEST_PATH_ZOT :<base>/foo/env_root/include/zot
FOO_TEST_PROG_FOO :<base>/foo/env_root/bin/foo.exe

----------
Foo_ROOT      :<base>/foo/cmake_root
ENV{Foo_ROOT} :<base>/foo/env_root

find_package\(Foo\)
FOO_TEST_FILE_FOO :<base>/foo/cmake_root/include/foo.h
FOO_TEST_FILE_ZOT :<base>/foo/cmake_root/include/zot/zot.h
FOO_TEST_PATH_FOO :<base>/foo/cmake_root/include
FOO_TEST_PATH_ZOT :<base>/foo/cmake_root/include/zot
FOO_TEST_PROG_FOO :<base>/foo/cmake_root/bin/foo.exe