diff --git a/tests/run-tests.py b/tests/run-tests.py
--- a/tests/run-tests.py
+++ b/tests/run-tests.py
@@ -1875,6 +1875,7 @@ class TestResult(unittest._TextTestResul
                         'changes)')
                 else:
                     self.stream.write('Accept this change? [n] ')
+                    self.stream.flush()
                     answer = sys.stdin.readline().strip()
                     if answer.lower() in ('y', 'yes'):
                         if test.path.endswith(b'.t'):