diff --git a/tests/sandbox/sandbox.html b/tests/sandbox/sandbox.html
index a01e9bfb..56d2fa5a 100644
--- a/tests/sandbox/sandbox.html
+++ b/tests/sandbox/sandbox.html
@@ -283,7 +283,17 @@
           setCode(content)
           document.getElementById("codeUri").value = f
         }
-        loadFile(pyodide.FS.currentPath+"/demo/demo.py")
+
+        const queryString = window.location.search;
+        console.log(queryString);
+        const urlParams = new URLSearchParams(queryString);
+        fileUri = urlParams.get("fileUri")
+        if (fileUri != null){
+          pyodide.FS.writeFile(pyodide.FS.currentPath+"/test_file.py", await (await fetch(fileUri)).text());
+          loadFile(pyodide.FS.currentPath+"/test_file.py")
+        }else{
+          loadFile(pyodide.FS.currentPath+"/demo/demo.py")
+        }
         //loadFile("/home/pyodide/tutorial/calculator/calculator.005.py")
         w2ui.sidebar.select(pyodide.FS.currentPath+"/demo/demo.py")