We can take
blend.php (src),
and separate the code from the test-cases:
utils.php (src), and separately
utils-test.php (src).
The directive require-once is a run-time instruction
which just goes to the require'd file and
(effectively) splices it into the current file,
and continues evaluating line-by-line.
(So it's reminiscent of java's import, but
require-once significantly more simple-minded.
Beware trampling on identifiers, and it's poor practice to
have any dangling tags / code in the require'd file.)
radford.edu