[11.x] fix: remove use of Redis::COMPRESSION_ZSTD_MIN

[calebdw]

Hello!

Related Issue: phpredis/phpredis#2487
php: 8.2
phpredis: 6.0.2

When running the tests locally I would receive ~40 failures for Undefined constant Redis::COMPRESSION_ZSTD_MIN. After a lot of debugging/recompiling phpredis/git bisecting I finally discovered that the constant was removed between phpredis 5.7.3 and 6.0.0 (COMPRESSION_ZSTD_MAX and COMPRESSION_ZSTD_DEFAULT are still defined).

Given that this constant is only referenced in the tests and other tests cases cover the max and default compression constants, I just opted to remove the references to this particular constant.

Thanks!

[vlakoff]

The constant has been brought back upstream, see phpredis/phpredis#2490. Of course, it will need a new phpredis release, to even just start propagating.

For the (long) time being, we might want to restore the unit tests that has been removed here, enclosing them with
if (defined(Redis::COMPRESSION_ZSTD_MIN)) { /* ... */ }. Even better, if the constant is missing, we may use the value 1 instead, which should be a safe fallback.

That being said, the tests with Redis::COMPRESSION_ZSTD_MIN and with Redis::COMPRESSION_ZSTD_MAX are identical, so I don't know if it is useful to keep both. Though, nowadays Redis::COMPRESSION_ZSTD_MIN may be negative (see phpredis/phpredis#2490 (comment)), thus maybe an integration test for such value might be relevant.

[driesvints]

Thanks @vlakoff. We can indeed restore the tests when the new version comes out.