tests: Workaround connection error race under Windows.

Appveyor test runs periodically fail with ConnectionDoesNotExist instead of the actual connection error. Try to mitigate that.

Author: elprans

tests/test_connect.py

@@ -121,12 +121,25 @@ def tearDown(self):
 
  super().tearDown()
 
+ async def _try_connect(self, **kwargs):
+ # On Windows the server sometimes just closes
+ # the connection sooner than we receive the
+ # actual error.
+ if _system == 'Windows':
+ for tried in range(3):
+ try:
+ return await self.cluster.connect(**kwargs)
+ except asyncpg.ConnectionDoesNotExistError:
+ pass
+
+ return await self.cluster.connect(**kwargs)
+
  async def test_auth_bad_user(self):
  with self.assertRaises(
  asyncpg.InvalidAuthorizationSpecificationError):
- await self.cluster.connect(user='__nonexistent__',
-  database='postgres',
-  loop=self.loop)
+ await self._try_connect(user='__nonexistent__',
+ database='postgres',
+ loop=self.loop)
 
  async def test_auth_trust(self):
  conn = await self.cluster.connect(
@@ -137,21 +150,9 @@ async def test_auth_reject(self):
  with self.assertRaisesRegex(
  asyncpg.InvalidAuthorizationSpecificationError,
  'pg_hba.conf rejects connection'):
- for tried in range(3):
- try:
- await self.cluster.connect(
- user='reject_user', database='postgres',
- loop=self.loop)
- except asyncpg.ConnectionDoesNotExistError:
- if _system == 'Windows':
- # On Windows the server sometimes just closes
- # the connection sooner than we receive the
- # actual error.
- continue
- else:
- raise
- else:
- break
+ await self._try_connect(
+ user='reject_user', database='postgres',
+ loop=self.loop)
 
  async def test_auth_password_cleartext(self):
  conn = await self.cluster.connect(
@@ -162,7 +163,7 @@ async def test_auth_password_cleartext(self):
  with self.assertRaisesRegex(
  asyncpg.InvalidPasswordError,
  'password authentication failed for user "password_user"'):
- await self.cluster.connect(
+ await self._try_connect(
  user='password_user', database='postgres',
  password='wrongpassword', loop=self.loop)
 
@@ -175,7 +176,7 @@ async def test_auth_password_md5(self):
  with self.assertRaisesRegex(
  asyncpg.InvalidPasswordError,
  'password authentication failed for user "md5_user"'):
- await self.cluster.connect(
+ await self._try_connect(
  user='md5_user', database='postgres', password='wrongpassword',
  loop=self.loop)