tests: Make default MICROPYPATH include extmod to find uasyncio.

tests/run-multitests.py

@@ -382,6 +382,9 @@ def main():
     cmd_parser.add_argument("files", nargs="+", help="input test files")
     cmd_args = cmd_parser.parse_args()
 
+    # clear search path to make sure tests use only builtin modules and those in extmod
+    os.environ['MICROPYPATH'] = os.pathsep + '../extmod'
+
     test_files = prepare_test_file_list(cmd_args.files)
     max_instances = max(t[1] for t in test_files)
 

tests/run-tests

@@ -628,8 +628,8 @@ the last matching regex is used:
         tests = args.files
 
     if not args.keep_path:
-        # clear search path to make sure tests use only builtin modules
-        os.environ['MICROPYPATH'] = ''
+        # clear search path to make sure tests use only builtin modules and those in extmod
+        os.environ['MICROPYPATH'] = os.pathsep + '../extmod'
 
     # Even if we run completely different tests in a different directory,
     # we need to access feature_check's from the same directory as the