[PATCH v2 7/8] tests/qemu-iotests/testrunner: Print diff to stderr in TAP mode

[Thomas Huth <thuth@redhat.com>]

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>
---
 tests/qemu-iotests/testrunner.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/testrunner.py b/tests/qemu-iotests/testrunner.py
index 9d20f51bb1..1f7ca1f2f9 100644
--- a/tests/qemu-iotests/testrunner.py
+++ b/tests/qemu-iotests/testrunner.py
@@ -404,7 +404,10 @@ def run_tests(self, tests: List[str], jobs: int = 1) -> bool:
             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':
-- 
2.27.0