fix APIv2 python attach test flake

The test was added in commit 1424f0958f, it can flake because the
attach test needs the message in the log. On slow CI systems this can
take longer. Add a retry logic which checks the container log every
second for up to 5 seconds. That should be plenty of time.

Fixes #17204

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

test/apiv2/python/rest_api/test_v2_0_0_container.py

@@ -146,6 +146,19 @@ class ContainerTestCase(APITestCase):
         )
         self.assertEqual(r.status_code, 204, r.text)
 
+        # wait for the log message to appear to avoid flakes on slow systems
+        # with the /attach?logs=true test below
+        for _ in range(5):
+            r = requests.get(
+                self.podman_url
+                + f"/v1.40/containers/{payload['Id']}/logs?stdout=true"
+            )
+            self.assertIn(r.status_code, (101, 200), r.text)
+            if r.content == b"\x01\x00\x00\x00\x00\x00\x00\x07podman\n":
+                break
+
+            time.sleep(1)
+
         r = requests.post(
             self.podman_url
             + f"/v1.40/containers/{payload['Id']}/attach?logs=true&stream=false"