^----------
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}: '<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}: ''

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     : ''
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

----------$