Tests: isolated binktermphp_test database harness with a fail-closed guard

[SkrawlCO]

TITLE: Tests: isolated binktermphp_test database harness with a fail-closed guard

Problem

Database-backed unit tests reach the database through Database::getInstance() or the application's .env DB_NAME, which is the configured application database. For example, UserManagerCreateTest drives scripts/user-manager.php against DB_NAME. There is no isolated test database and nothing stops a test run from writing to a live board's database.

Impact

Running the unit suite on a machine with a configured board risks writing fixtures into production data. Contributors cannot safely add tests for database-backed behavior.

Repair

• tests/Unit/Support/TestDatabase.php: the shared way to get a PDO for the isolated binktermphp_test database. It uses DB_HOST/DB_PORT/DB_USER/DB_PASS, never reads DB_NAME, never calls Database::getInstance(), and verifies current_database() before returning the connection.
• Database::setInstanceForTesting(PDO $pdo): routes every Database::getInstance() call, including those inside production code under test, to that connection. It checks current_database() itself, independently of the helper, and refuses anything except exactly binktermphp_test, leaving the existing singleton untouched. Database::resetInstanceForTesting() drops the singleton.
• Production code paths are unchanged; the new methods are test-only.

Proof

• tests/Unit/DatabaseTestIsolationTest.php, with no database server (PDO stubs):

  • connections reporting binktermphp, postgres, binktermphp_test_copy or an empty name are refused, and the singleton is unchanged;
  • a binktermphp_test connection is installed and session-initialized (SET TIME ZONE 'UTC');
  • reset clears the singleton.

  It errors on the current branch and passes with the change.

• tests/Unit/TestDatabaseConnectionTest.php is the end-to-end check against a real binktermphp_test database. It skips when pdo_pgsql or the database is unavailable. (Proof against a real PostgreSQL instance is recorded separately.)

• The rest of tests/Unit is unchanged.