diff --git a/tests/run-tests.py b/tests/run-tests.py
index 093656299f..392597c6d2 100755
--- a/tests/run-tests.py
+++ b/tests/run-tests.py
@@ -456,12 +456,12 @@ def run_micropython(pyb, args, test_file, test_file_abspath, is_special=False):
 
         if is_special:
             # check for any cmdline options needed for this test
-            args = [MICROPYTHON]
+            cmdlist = [MICROPYTHON]
             with open(test_file, "rb") as f:
                 line = f.readline()
                 if line.startswith(b"# cmdline:"):
                     # subprocess.check_output on Windows only accepts strings, not bytes
-                    args += [str(c, "utf-8") for c in line[10:].strip().split()]
+                    cmdlist += [str(c, "utf-8") for c in line[10:].strip().split()]
 
             # run the test, possibly with redirected input
             try:
@@ -497,10 +497,10 @@ def run_micropython(pyb, args, test_file, test_file_abspath, is_special=False):
                         return get()
 
                     with open(test_file, "rb") as f:
-                        # instead of: output_mupy = subprocess.check_output(args, stdin=f)
+                        # instead of: output_mupy = subprocess.check_output(cmdlist, stdin=f)
                         master, slave = pty.openpty()
                         p = subprocess.Popen(
-                            args, stdin=slave, stdout=slave, stderr=subprocess.STDOUT, bufsize=0
+                            cmdlist, stdin=slave, stdout=slave, stderr=subprocess.STDOUT, bufsize=0
                         )
                         banner = get(True)
                         output_mupy = banner + b"".join(send_get(line) for line in f)
@@ -519,7 +519,7 @@ def run_micropython(pyb, args, test_file, test_file_abspath, is_special=False):
                         os.close(slave)
                 else:
                     output_mupy = subprocess.check_output(
-                        args + [test_file], stderr=subprocess.STDOUT
+                        cmdlist + [test_file], stderr=subprocess.STDOUT
                     )
             except subprocess.CalledProcessError:
                 return b"CRASH"
@@ -585,7 +585,12 @@ def run_micropython(pyb, args, test_file, test_file_abspath, is_special=False):
 
     if is_special or test_file_abspath in tests_with_regex_output:
         # convert parts of the output that are not stable across runs
-        with open(test_file + ".exp", "rb") as f:
+        # Prefer emitter-specific expected output.
+        exp_file = test_file + "." + args.emit + ".exp"
+        if not os.path.isfile(exp_file):
+            # Fall back to generic expected output.
+            exp_file = test_file + ".exp"
+        with open(exp_file, "rb") as f:
             lines_exp = []
             for line in f.readlines():
                 if line == b"########\n":