test: replace empty() with isset()

Author: kenjis

phpstan-baseline.php

@@ -431,11 +431,6 @@
 	'count' => 1,
 	'path' => __DIR__ . '/tests/Unit/UserTest.php',
 ];
-$ignoreErrors[] = [
-	'message' => '#^Construct empty\\(\\) is not allowed\\. Use more strict comparison\\.$#',
-	'count' => 1,
-	'path' => __DIR__ . '/tests/_support/Config/Registrar.php',
-];
 $ignoreErrors[] = [
 	'message' => '#^Call to function model with CodeIgniter\\\\Shield\\\\Models\\\\TokenLoginModel\\:\\:class is discouraged\\.$#',
 	'count' => 1,

tests/_support/Config/Registrar.php

@@ -136,7 +136,7 @@ public static function Database()
 
         // Under GitHub Actions, we can set an ENV var named 'DB'
         // so that we can test against multiple databases.
-        if (($group = getenv('DB')) && ! empty(self::$dbConfig[$group])) {
+        if (($group = getenv('DB')) && ! isset(self::$dbConfig[$group])) {
             $config['tests'] = self::$dbConfig[$group];
         }