Correct DatabaseTenancyBootstrapperTest (#1466)

### Test for DatabaseTenancyBootstrapper throwing an exception when
`DB_URL` is set

The test meant to cover this set `central.url` before creating a tenant.
That made the `CreateDatabase` job fail with a QueryException (it tried
to use the URL host as a database name). The bootstrapper's check was
never reached, and the exception that the test intended to cover wasn't
ever thrown in the end. The test passed for the wrong reason.

Fixed by creating the tenant first, setting the url only after that, and
asserting that `tenancy()->initialize()` throws the bootstrapper's
specific exception.

### Reference env variable that Laravel uses now (`DB_URL`) instead of
`DATABASE_URL`

Changed all `DATABASE_URL` references in Tenancy to `DB_URL`. [In
Laravel
11](96508d43ec (diff-e4382b565f69d02de16eef89c8d5ca2b60a679ffca90ab8b7d85fbd78f30075bR35)),
the `DATABASE_URL` env variable got renamed to `DB_URL` in
`config/database.php`. The env var got renamed quite a while ago, so
referencing `DATABASE_URL` in Tenancy's comments and tests was a bit
confusing.

### Minor cleanup

The `harden prevents tenants from using the database of another tenant`
test now reads the central connection name from
`config('tenancy.database.central_connection')` instead of hardcoding
`'central'` for consistency with the other tests.

tests/Bootstrappers/DatabaseTenancyBootstrapperTest.php

@@ -12,7 +12,6 @@ use Stancl\Tenancy\Listeners\RevertToCentralContext;
 use Stancl\Tenancy\Tests\Etc\Tenant;
 use Illuminate\Support\Str;
 use Illuminate\Support\Facades\DB;
-use Illuminate\Database\QueryException;
 use Stancl\Tenancy\Database\TenantDatabaseManagers\MySQLDatabaseManager;
 use Stancl\Tenancy\Database\TenantDatabaseManagers\SQLiteDatabaseManager;
 use Stancl\Tenancy\Database\TenantDatabaseManagers\PostgreSQLDatabaseManager;
@@ -116,7 +115,9 @@ test('harden prevents tenants from using the database of another tenant', functi
         expect(fn () => tenancy()->initialize($tenant))->toThrow(RuntimeException::class);
 
         // Connection should be reverted back to central
-        expect(DB::connection()->getName())->toBe('central');
+        $centralConnection = config('tenancy.database.central_connection');
+
+        expect(DB::connection()->getName())->toBe($centralConnection);
     } else {
         expect(fn() => tenancy()->initialize($tenant))->not()->toThrow(Throwable::class);
 
@@ -128,25 +129,22 @@ test('harden prevents tenants from using the database of another tenant', functi
     'hardening disabled' => false,
 ])->with('db_managers');
 
-test('database tenancy bootstrapper throws an exception if DATABASE_URL is set', function (string|null $databaseUrl) {
-    config(['database.connections.central.url' => $databaseUrl]);
-
+test('database tenancy bootstrapper throws an exception if DB_URL is set', function (string|null $databaseUrl) {
     config(['tenancy.bootstrappers' => [DatabaseTenancyBootstrapper::class]]);
 
     Event::listen(TenantCreated::class, JobPipeline::make([CreateDatabase::class])->send(function (TenantCreated $event) {
         return $event->tenant;
     })->toListener());
 
+    $tenant = Tenant::create();
+
+    config(['database.connections.central.url' => $databaseUrl]);
+
     if ($databaseUrl) {
-        expect(fn() => Tenant::create())->toThrow(QueryException::class);
+        expect(fn() => tenancy()->initialize($tenant))
+            ->toThrow(Exception::class, 'The template connection must NOT have URL defined.');
     } else {
-        expect(function() {
-            $tenant1 = Tenant::create();
-
-            pest()->artisan('tenants:migrate');
-
-            tenancy()->initialize($tenant1);
-        })->not()->toThrow(Throwable::class);
+        expect(fn() => tenancy()->initialize($tenant))->not()->toThrow(Throwable::class);
     }
 })->with(['abc.us-east-1.rds.amazonaws.com', null]);