diff --git a/test/watchCases/plugins/define-plugin/webpack.config.js b/test/watchCases/plugins/define-plugin/webpack.config.js
index 31a075ce7c2..b2d1be84d7a 100644
--- a/test/watchCases/plugins/define-plugin/webpack.config.js
+++ b/test/watchCases/plugins/define-plugin/webpack.config.js
@@ -19,7 +19,11 @@ module.exports = {
 			}, []),
 			TEST_VALUE3: webpack.DefinePlugin.runtimeValue(() => {
 				return JSON.stringify(fs.readFileSync(valueFile, "utf-8").trim());
-			}, true)
+			}, true),
+			TEST_FN_ARG1: webpack.DefinePlugin.runtimeValue((module) => {
+				return typeof module === 'object'; // or `module instanceof ?what?`
+			})
+			
 		})
 	]
 };