Test binaries abort when a name filter matches tests that construct a DbHandler (CONFIG parses the test argv)

[erans]

Found while working on #80. Pre-existing on main, independent of that change.

Reproduce

cargo test --lib sql_injection

Observed

error: unexpected argument '--nocapture' found

  tip: a similar argument exists: '--no-tcp'

Usage: <test-binary> --no-tcp
error: test failed

or, with a bare filter, the process exits non-zero before running the matched tests.

Cause

config::CONFIG is a lazy_static whose initializer calls Config::load() → Config::parse() (src/config.rs). In a test binary, argv belongs to the libtest harness, not to pgsqlite, so clap sees --nocapture or a filter string, rejects it, and calls process::exit.

Anything that touches CONFIG in a test binary triggers this. db_handler::tests::test_sql_injection_patterns constructs a DbHandler, which initializes lazy statics that dereference CONFIG — src/session/state.rs:15, src/cache/statement_pool.rs:35, src/cache/execution.rs:130, src/cache/result_cache.rs:246.

Impact

• cargo test -- --nocapture is unusable for any test that reaches CONFIG, which is most integration tests, since session creation initializes those caches. This makes debugging test failures materially harder.
• Any cargo test --lib <filter> whose filter matches those db_handler tests aborts rather than running.
• It is a trap for new code: Add --hide-internal-tables flag to hide __pgsqlite_* tables from client sqlite_master queries (#80) #85 had to design around it explicitly, gating its feature flag behind a plain AtomicBool set from main rather than reading CONFIG at the call sites, purely so the feature would be testable.

Possible fixes

• Have Config::load() fall back to Config::parse_from(["pgsqlite"]) (defaults only) when running under a test harness — detectable via cfg!(test) for lib tests, though not for integration test binaries.
• Or use try_parse() and fall back to defaults on error instead of exiting, at least when argv[0] is not the pgsqlite binary.
• Or make the tests that construct a DbHandler inject a Config rather than relying on the global.