test: fix the test case

Author: SoonIter

packages/rspack-test-tools/tests/configCases/library/modern-module-asset-entry/rspack.config.js

@@ -1,3 +1,5 @@
+const assert = require("assert");
+
 /** @type {import("@rspack/core").Configuration} */
 module.exports = {
 	context: __dirname,
@@ -44,8 +46,10 @@ module.exports = {
 						const js = list.find(item => item.endsWith("js"));
 						const jsContent = assets[js].source().toString();
 
-						/import img_namespaceObject from ['"]\.\/static\/img\/img\.png['"]/.test(jsContent);
-						/export\s{\simg_namespaceObject\sas\sdefault\s}/.test(jsContent);
+						const preseveImport = /import img_namespaceObject from ['"]\.\/static\/img\/img\.png['"]/.test(jsContent);
+						assert(preseveImport);
+						const hasExports = /export\s{\simg_namespaceObject\sas\sdefault\s}/.test(jsContent);
+						assert(hasExports);
 					})
 				});
 			}