tests/qemu-iotests/testrunner: Print diff to stderr in TAP mode

When running in TAP mode, stdout is reserved for the TAP protocol.
To see the "diff" of the failed test, we have to print it to
stderr instead.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20220209101530.3442837-8-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/tests/qemu-iotests/testrunner.py b/tests/qemu-iotests/testrunner.py
index 0eace147b8fcb37fa605c65108868e2932d26043..9a942739754f72cdd846871df8ebddcd6d6aba88 100644 (file)
--- a/tests/qemu-iotests/testrunner.py
+++ b/tests/qemu-iotests/testrunner.py
@@ -404,7 +404,10 @@ class TestRunner(ContextManager['TestRunner']):
             if res.status == 'fail':
                 failed.append(name)
                 if res.diff:
-                    print('\n'.join(res.diff))
+                    if self.tap:
+                        print('\n'.join(res.diff), file=sys.stderr)
+                    else:
+                        print('\n'.join(res.diff))
             elif res.status == 'not run':
                 notrun.append(name)
             elif res.status == 'pass':