Merge ~pappacena/launchpad:testfix-librarian-client-race-condition into launchpad:master

[Thiago F. Pappacena]

[testfix] Avoiding race condition at librarian client test

[Colin Watson (cjwatson)]

review: Approve

befb367... by Thiago F. Pappacena on 2020-08-12

Setting a smaller timeout at test

diff --git a/lib/lp/services/librarian/client.py b/lib/lp/services/librarian/client.py
index 737d9e4..ba18805 100644
--- a/lib/lp/services/librarian/client.py
+++ b/lib/lp/services/librarian/client.py
@@ -88,6 +88,7 @@ class FileUploadClient:
         # it will be shared between threads. The easiest way of making this
         # class thread safe is by storing all state in a thread local.
         self.state = threading.local()
+        self.state.s_poll_timeout = 0
 
     def _connect(self):
         """Connect this client.
@@ -115,7 +116,7 @@ class FileUploadClient:
         del self.state.f
 
     def _checkError(self):
-        poll_result = self.state.s_poll.poll(0)
+        poll_result = self.state.s_poll.poll(self.state.s_poll_timeout)
         if poll_result:
             fileno, event = poll_result[0]
             # Accepts any event that contains input data. Even if we
diff --git a/lib/lp/services/librarian/tests/test_client.py b/lib/lp/services/librarian/tests/test_client.py
index 34dce5f..3b406c1 100644
--- a/lib/lp/services/librarian/tests/test_client.py
+++ b/lib/lp/services/librarian/tests/test_client.py
@@ -252,7 +252,16 @@ class LibrarianClientTestCase(TestCase):
             'librarian', upload_host=upload_host, upload_port=upload_port)
 
         client = LibrarianClient()
-
+        # Artificially increases timeout to avoid race condition.
+        # The fake server is running in another thread, and we are sure it
+        # will (eventually) reply with an error message. So, let's just wait
+        # until that message arrives.
+        client.state.s_poll_timeout = 120
+
+        # Please, note the mismatch between file size (7) and its actual size
+        # of the content (6). This is intentional, to make sure we are raising
+        # the error coming from the fake server (and not the local check
+        # right after, while uploading the file).
         self.assertRaisesRegex(
             UploadFailed, 'Server said early: STORE 7 sample.txt',
             client.addFile, 'sample.txt', 7, StringIO('sample'), 'text/plain')