diff --git a/tests/Calls/FunctionCallsTest.php b/tests/Calls/FunctionCallsTest.php
index c16613b..891b7cd 100644
--- a/tests/Calls/FunctionCallsTest.php
+++ b/tests/Calls/FunctionCallsTest.php
@@ -187,6 +187,16 @@ protected function getRule(): Rule
 						1 => Blade::class,
 					],
 				],
+				[
+					'function' => '\Foo\Bar\Waldo\config()',
+					'allowIn' => [
+						'../src/disallowed-allow/*.php',
+						'../src/*-allow/*.*',
+					],
+					'disallowParams' => [
+						1 => 'string-key',
+					],
+				],
 			]
 		);
 	}
@@ -287,6 +297,10 @@ public function testRule(): void
 				'Calling Foo\Bar\Waldo\mocky() is forbidden, mocking Blade is not allowed.',
 				83,
 			],
+			[
+				'Calling Foo\Bar\Waldo\config() is forbidden, because reasons',
+				91,
+			],
 		]);
 		// Based on the configuration above, no errors in this file:
 		$this->analyse([__DIR__ . '/../src/disallowed-allow/functionCalls.php'], [
diff --git a/tests/libs/Functions.php b/tests/libs/Functions.php
index 289dc51..37110de 100644
--- a/tests/libs/Functions.php
+++ b/tests/libs/Functions.php
@@ -39,3 +39,11 @@ function waldo(string $name = '', string $value = '', int $expires = 0, string $
 function mocky(string $className): void
 {
 }
+
+
+/**
+ * @param array|string|null $key
+ */
+function config($key = null)
+{
+}
diff --git a/tests/src/disallowed-allow/functionCalls.php b/tests/src/disallowed-allow/functionCalls.php
index 5d5151b..a2ae87f 100644
--- a/tests/src/disallowed-allow/functionCalls.php
+++ b/tests/src/disallowed-allow/functionCalls.php
@@ -84,3 +84,8 @@
 
 // not disallowed
 hash((new stdClass())->property . 'foo', 'NAH');
+
+// not disallowed param
+\Foo\Bar\Waldo\config(['key' => 'string']);
+// allowed by path
+\Foo\Bar\Waldo\config('string-key');
diff --git a/tests/src/disallowed/functionCalls.php b/tests/src/disallowed/functionCalls.php
index 13470de..cb8893c 100644
--- a/tests/src/disallowed/functionCalls.php
+++ b/tests/src/disallowed/functionCalls.php
@@ -84,3 +84,8 @@
 
 // not disallowed
 hash((new stdClass())->property . 'foo', 'NAH');
+
+// not disallowed param
+\Foo\Bar\Waldo\config(['key' => 'string']);
+// disallowed param
+\Foo\Bar\Waldo\config('string-key');