Fixed: The HTTP cache's role tests hold what happens without APCu (file-store and S1 legs)

[se7enxweb]

What fails

Since the HTTP cache's roles were merged (8f94bd1, Merge branch 'wip/g4-cache'),
the Tests workflow on main has failed on every leg without APCu: the six
file-store legs (PHP 8.0 … PHP 8.5 (file store)) and PHP 8.0, minimal hosting (S1).

• First run with it: https://github.com/cjw-network/request-shield/actions/runs/37900483320
• Latest run on main (a92a37b): https://github.com/cjw-network/request-shield/actions/runs/38043321121
  • PHP 8.3 (file store): https://github.com/cjw-network/request-shield/actions/runs/38043321121/job/114187792382
  • PHP 8.0, minimal hosting (S1): https://github.com/cjw-network/request-shield/actions/runs/38043321121/job/114187761237

Each of these legs fails the same two tests:

FAIL  CacheTest > RSF04-03 end to end, a page per role (0039): ...
      a session the shield does not know yet: the application runs
FAIL  ShowcaseTest > RSF04-03 showcase, the tab "Cache": ...
      member B: the members' page member A made --
FAIL - 518 passed, 2 failed, 13 skipped (PHP 8.3.35)

The legs with APCu pass.

Why

Roles are remembered in APCu only (0039). Without APCu they stay off, as the
proposal says: a session's page is the visitor's own, made by the application
each time, and nothing is kept for it. The library does exactly that. The two
tests, however, expect a member's page from the cache on every leg. Without
APCu, the first test never sees the X-RS-Cache: miss it waits for, and the
showcase test never sees member A's page served to member B.

So the code is right and the tests ask for something the proposal rules out
without APCu.

The fix

Tests only, no change in src/:

• tests/helpers.php: serverApcu() says whether the servers a test starts
  (php -S, PHP-FPM) have APCu: the extension is loaded (they do not need
  apc.enable_cli) and TESTS_HOSTING is not minimal.
• tests/CacheTest.php, "a page per role": with APCu, unchanged. Without it,
  the test holds what 0039 promises: a session's page comes from the
  application each time (the run counter goes up by two for two requests),
  nothing is kept for it (no X-RS-Cache: miss that a later request could
  hit), and anonymous visitors still get their kept page, never a session's.
• tests/ShowcaseTest.php, the tab "Cache": with APCu, unchanged. Without it,
  member B gets the members' page from the application, not from the cache,
  and not the second time either.

Tested

• The fork's CI, the full matrix with this commit on top of a92a37b: the
  file-store and S1 legs pass both tests. The other failures in that run are
  the flaky disk-cap test on PHP 8.0 + APCu (Fixed: The disk's cap test no longer depends on the clock moving to the next second #7) and a PHP
  8.0.30 segfault on PHP 8.0 + APCu, single file (PHP 8.0.30 legs: segfaults (exit 139) in FeedsTest and status 0 from the demo's built-in server #9).
  https://github.com/se7enxweb/request-shield/actions/runs/38120981093
• Locally (PHP 8.5.11), php tests/run.php RSF04-03:
  • with APCu: 23 passed, 0 failed;
  • with TESTS_HOSTING=minimal: both tests fail on a92a37b and pass with this commit.