diff --git a/tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php b/tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php
index 41ea389b6..72a04febe 100644
--- a/tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php
+++ b/tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php
@@ -131,30 +131,31 @@ public function test_run_with_badly_named_errors() {
 	public function test_run_with_duplicated_named_errors() {
 		// Initialize the Check_Context with a plugin path that mimics the directory structure.
 		$check_context = new Check_Context( UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/load.php' );
-		
+
 		// Create an empty Check_Result instance for this context.
 		$check_result = new Check_Result( $check_context );
 
 		// Initialize the File_Type_Check instance.
 		$check = new File_Type_Check();
 
-		// Use reflection to make check_files accessible.
-		$reflection = new \ReflectionClass( $check );
-		$checkFilesMethod = $reflection->getMethod('check_files');
-		$checkFilesMethod->setAccessible(true);
+		// Use reflection to make protected method accessible.
+		$reflection       = new ReflectionClass( $check );
+		$checkFilesMethod = $reflection->getMethod( 'look_for_badly_named_files' );
+		$checkFilesMethod->setAccessible( true );
 
 		// Define the custom file list with duplicate names as they would appear in a plugin directory.
-		$customFiles = [
-				UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/custom-file.php',
-				UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/Custom-File.php',
-				UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/custom-FILE.php'
-		];
+		$customFiles = array(
+			UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/custom-file.php',
+			UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/Custom-File.php',
+			UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/custom-FILE.php',
+		);
 
-		// Invoke check_files with the Check_Result instance and custom file list.
-		$result = $checkFilesMethod->invoke($check, $check_result, $customFiles);
+		// Invoke method with the Check_Result instance and custom file list.
+		$result = $checkFilesMethod->invoke( $check, $check_result, $customFiles );
+
+		$errors = $check_result->get_errors();
 
-		// Assert that check_files handles the custom file list with duplicates correctly.
-		$this->assertTrue($result->has_errors(), "The check_files method should detect errors for duplicate file names.");
+		$this->assertCount( 1, wp_list_filter( $errors['custom-file.php'][0][0], array( 'code' => 'duplicated_files' ) ) );
 	}
 
 	public function test_run_with_library_core_errors() {