Add testcase

tests/cases/fourslash/javascriptModules25.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts'/>
+// @allowJs: true
+
+// @Filename: mod.js
+//// function foo() { return {a: true}; }
+//// module.exports.a = foo;
+
+// @Filename: app.js
+//// import * as mod from "./mod"
+//// mod./**/
+
+goTo.marker();
+verify.completionListContains('a');