diff --git a/src/pyodide.js b/src/pyodide.js
index cbc677b78..8b46a19a9 100644
--- a/src/pyodide.js
+++ b/src/pyodide.js
@@ -2,6 +2,13 @@
  * The main bootstrap script for loading pyodide.
  */
 
+// Regexp for validating package name and URI
+var package_name_regexp = '[a-zA-Z0-9_\-]+'
+var package_uri_regexp = new RegExp(
+     '^(?:https?|file)://.*?(' + package_name_regexp + ').js$');
+var package_name_regexp = new RegExp('^' + package_name_regexp + '$');
+
+
 var languagePluginLoader = new Promise((resolve, reject) => {
   // This is filled in by the Makefile to be either a local file or the
   // deployed location. TODO: This should be done in a less hacky
@@ -13,20 +20,38 @@ var languagePluginLoader = new Promise((resolve, reject) => {
   var packages = undefined;
   let loadedPackages = new Set();
 
+  let _uri_to_package_name = (package_uri) => {
+    // Generate a unique package name from URI
+
+    if (package_name_regexp.test(package_uri)) {
+      return package_uri;
+    } else if (package_uri_regexp.test(package_uri)) {
+      var match = package_uri_regexp.exec(package_uri);
+      // Get the regexp group corresponding to the package name
+      return match[1];
+    } else {
+      return null;
+    }
+  };
+
+
   let loadPackage = (names) => {
     // DFS to find all dependencies of the requested packages
     let packages = window.pyodide.packages.dependencies;
     let queue = new Array(names);
     let toLoad = new Set();
     while (queue.length) {
-      const package = queue.pop();
-      var valid_package_name_regexp = new RegExp('^[a-zA-Z0-9_\-]+$');
-      console.log(package + valid_package_name_regexp.test(package));
-      if (!valid_package_name_regexp.test(package)) {
-          console.log(`Invalid package name '${package}'`);
+      const package_uri = queue.pop();
+
+      const package = _uri_to_package_name(package_uri);
+
+      if (package == null) {
+          console.log(`Invalid package name or URI '${package_uri}'`);
           break;
       }
 
+      console.log(`Loading ${package} from ${package_uri}`);
+
       if (!loadedPackages.has(package)) {
         toLoad.add(package);
         if (packages.hasOwnProperty(package)) {
diff --git a/test/conftest.py b/test/conftest.py
index a904606c9..1d1b93bf9 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -53,6 +53,9 @@ class SeleniumWrapper:
         logs = self.driver.execute_script("return window.logs")
         return '\n'.join(str(x) for x in logs)
 
+    def clean_logs(self):
+        self.driver.execute_script("window.logs = []")
+
     def run(self, code):
         return self.run_js(
             'return pyodide.runPython({!r})'.format(code))
@@ -145,11 +148,10 @@ if pytest is not None:
     def selenium(_selenium_cached):
         # selenium instance cached at the module level
         try:
-            # clean selenium logs for each test run
-            _selenium_cached.driver.execute_script("window.logs = []")
+            _selenium_cached.clean_logs()
             yield _selenium_cached
         finally:
-            print('\n'.join(str(x) for x in _selenium_cached.logs))
+            print(_selenium_cached.logs)
 
 
 PORT = 0