[PBCKP-358] fix CatchupTest.test_unclean_(delta|ptrack)_catchup

and BugTest.test_minrecpoint_on_replica as well

Tests were broken with introduction of "startness" handling in
    9924ab014 [PBCKP-304] extended testgres.PosgresNode to ...
since tests uses os.kill directly.

tests/catchup.py

@@ -972,7 +972,7 @@ class CatchupTest(ProbackupTest, unittest.TestCase):
         self.set_auto_conf(dst_pg, dst_options)
         dst_pg.slow_start()
         self.assertNotEqual(dst_pg.pid, 0, "Cannot detect pid of running postgres")
-        os.kill(dst_pg.pid, signal.SIGKILL)
+        dst_pg.kill()
 
         # preparation 3: make changes on master (source)
         src_pg.pgbench_init(scale = 10)
@@ -1061,7 +1061,7 @@ class CatchupTest(ProbackupTest, unittest.TestCase):
         self.set_auto_conf(dst_pg, dst_options)
         dst_pg.slow_start()
         self.assertNotEqual(dst_pg.pid, 0, "Cannot detect pid of running postgres")
-        os.kill(dst_pg.pid, signal.SIGKILL)
+        dst_pg.kill()
 
         # preparation 3: make changes on master (source)
         src_pg.pgbench_init(scale = 10)

tests/helpers/ptrack_helpers.py

@@ -3,6 +3,7 @@ import os
 import gc
 import unittest
 from sys import exit, argv, version_info
+import signal
 import subprocess
 import shutil
 import six
@@ -190,6 +191,14 @@ class PostgresNodeExtended(testgres.PostgresNode):
             self.is_started = False
             return result
 
+    def kill(self, someone = None):
+        if self.is_started:
+            sig = signal.SIGKILL if os.name != 'nt' else signal.SIGBREAK
+            if someone == None:
+                os.kill(self.pid, sig)
+            else:
+                os.kill(self.auxiliary_pids[someone][0], sig)
+            self.is_started = False
 
 class ProbackupTest(object):
     # Class attributes

tests/pgpro2068.py

@@ -85,7 +85,6 @@ class BugTest(ProbackupTest, unittest.TestCase):
         # get pids of replica background workers
         startup_pid = replica.auxiliary_pids[ProcessType.Startup][0]
         checkpointer_pid = replica.auxiliary_pids[ProcessType.Checkpointer][0]
-        bgwriter_pid = replica.auxiliary_pids[ProcessType.BackgroundWriter][0]
 
         # break checkpointer on UpdateLastRemovedPtr
         gdb_checkpointer = self.gdb_attach(checkpointer_pid)
@@ -108,7 +107,7 @@ class BugTest(ProbackupTest, unittest.TestCase):
         pgbench.stdout.close()
 
         # kill someone, we need a crash
-        os.kill(int(bgwriter_pid), 9)
+        replica.kill(someone=ProcessType.BackgroundWriter)
         gdb_recovery._execute('detach')
         gdb_checkpointer._execute('detach')