diff --git a/system/Test/FeatureTestTrait.php b/system/Test/FeatureTestTrait.php
index 600e490ab7e9..4e98fb505343 100644
--- a/system/Test/FeatureTestTrait.php
+++ b/system/Test/FeatureTestTrait.php
@@ -400,7 +400,7 @@ protected function populateGlobals(string $name, Request $request, ?array $param
             $request->setGlobal($name, $params);
             $request->setGlobal(
                 'request',
-                $request->fetchGlobal('post') + $request->fetchGlobal('get'),
+                (array) $request->fetchGlobal('post') + (array) $request->fetchGlobal('get'),
             );
         }
 
diff --git a/tests/system/Database/BaseConnectionTest.php b/tests/system/Database/BaseConnectionTest.php
index a9fcab80622b..be8f7d2642ad 100644
--- a/tests/system/Database/BaseConnectionTest.php
+++ b/tests/system/Database/BaseConnectionTest.php
@@ -313,7 +313,7 @@ public function testEscapeIdentifiers(string $item, string $expected): void
     }
 
     /**
-     * @return array<string, list<string>>
+     * @return iterable<string, list<string>>
      */
     public static function provideEscapeIdentifiers(): iterable
     {
@@ -335,7 +335,7 @@ public function testEscapeIdentifier(string $item, string $expected): void
     }
 
     /**
-     * @return array<string, list<string>>
+     * @return iterable<string, list<string>>
      */
     public static function provideEscapeIdentifier(): iterable
     {
diff --git a/tests/system/Database/Live/OCI8/ConnectionTest.php b/tests/system/Database/Live/OCI8/ConnectionTest.php
index 6fe89302337f..2124bc2c7e32 100644
--- a/tests/system/Database/Live/OCI8/ConnectionTest.php
+++ b/tests/system/Database/Live/OCI8/ConnectionTest.php
@@ -53,7 +53,7 @@ public function testIsValidDSN(string $dsn): void
     }
 
     /**
-     * @return array<string, list<string>>
+     * @return iterable<string, list<string>>
      */
     public static function provideIsValidDSN(): iterable
     {