test: replication-py/init_storage.test.py

Found that test failed in 2 common places when it tried to start the
replica and wait it within 'JOIN' either 'SUBSCRIBE' test parts.
It used to wait for replica start check the 'wait_until_started()'
function 'TarantoolServer' class from test-run repository. But it
didn't try resolve connection issues on replica creation, like:

  [30534] main/103/replica I> connecting to 1 replicas
  [30534] main/112/applier/localhost:49168 I> can't connect to master
  [30534] main/112/applier/localhost:49168 sio.c:208 !> SystemError connect to 127.0.0.1:49168, called on fd 27, aka 127.0.0.1:47954: Connection refused
  [30534] main/112/applier/localhost:49168 I> will retry every 0.10 second
  [30534] main/112/applier/localhost:49168 I> remote master c5d480c3-219c-11eb-ac14-080027727614 at 127.0.0.1:49168 running Tarantool 2.7.0
  [30534] main/103/replica I> connected to 1 replicas
  [30534] main/103/replica I> bootstrapping replica from c5d480c3-219c-11eb-ac14-080027727614 at 127.0.0.1:49168
  [30534] main/112/applier/localhost:49168 I> can't read row
  [30534] main/112/applier/localhost:49168 box.cc:183 E> ER_READONLY: Can't modify data because this instance is in read-only mode.
  [30534] main/103/replica box.cc:183 E> ER_READONLY: Can't modify data because this instance is in read-only mode.
  [30534] main/103/replica F> can't initialize storage: Can't modify data because this instance is in read-only mode.
  [30534] main/103/replica F> can't initialize storage: Can't modify data because this instance is in read-only mode.

To resolve it the test was changed to be able to catch exception
'TarantoolStartError' from test-run. Also the test should have the
ability to be restarted by test-run using fragile list and in this way
'crash_expected' flag was disabled to let the test fail with exception.

Needed by #4949

Author: avtikhon

test/replication-py/init_storage.test.py

@@ -1,5 +1,6 @@
 import os
 import glob
+from lib.tarantool_server import TarantoolStartError
 from lib.tarantool_server import TarantoolServer
 
 # master server
@@ -64,17 +65,35 @@
 
 print 'waiting reconnect on JOIN...'
 server.start()
-replica.wait_until_started()
-print 'ok'
+try:
+    # Replica may fail to start due connection issues may occur, check
+    # gh-4949. Also the test should have the ability to be restarted by
+    # test-run using fragile list and in this way 'crash_expected' flag
+    # should be disabled to let the test fail with exception.
+    replica.crash_expected = True
+    replica.wait_until_started()
+except TarantoolStartError:
+    print 'not ok - server failed to start'
+else:
+    print 'ok'
 
 replica.stop()
 server.stop()
 
 print 'waiting reconnect on SUBSCRIBE...'
 replica.start(wait=False)
 server.start()
-replica.wait_until_started()
-print 'ok'
+try:
+    # Replica may fail to start due connection issues may occur, check
+    # gh-4949. Also the test should have the ability to be restarted by
+    # test-run using fragile list and in this way 'crash_expected' flag
+    # should be disabled to let the test fail with exception.
+    replica.crash_expected = True
+    replica.wait_until_started()
+except TarantoolStartError:
+    print 'not ok - server failed to start'
+else:
+    print 'ok'
 
 replica.stop()
 replica.cleanup()

test/replication-py/suite.ini

@@ -4,10 +4,11 @@ script =  master.lua
 description = tarantool/box, replication
 is_parallel = True
 fragile = {
-    "retries": 10,
+    "retries": 50,
     "tests": {
         "init_storage.test.py": {
-            "issues": [ "gh-4949" ]
+            "issues": [ "gh-4949" ],
+            "checksums": [ "9b4235bb6bb9d76aa6a1f7dc8f088075", "4c5fc871955a3166d67fbfa9f254f68a", "bc2781acdb5745d01da2f533a0d519f9" ]
         },
         "conflict.test.py": {
             "issues": [ "gh-4980" ]