Fix catchup tests for dry-run option

tests/catchup.py

@@ -1470,13 +1470,18 @@ def test_dry_run_catchup_full(self):
             pg_options = { 'wal_log_hints': 'on' }
             )
         src_pg.slow_start()
-        src_pg.safe_psql(
-            "postgres",
-            "CREATE TABLE ultimate_question(answer int)")
 
         # preparation 2: make clean shutdowned lagging behind replica
         dst_pg = self.make_empty_node(os.path.join(module_name, self.fname, 'dst'))
 
+        src_pg.safe_psql(
+            "postgres",
+            "CREATE TABLE ultimate_question(answer int)")
+        src_pg.pgbench_init(scale = 10)
+        pgbench = src_pg.pgbench(options=['-T', '10', '--no-vacuum'])
+        pgbench.wait()
+        src_pg.safe_psql("postgres", "INSERT INTO ultimate_question VALUES(42)")
+
         # save the condition before dry-run
         content_before = self.pgdata_content(dst_pg.data_dir)
 
@@ -1496,10 +1501,12 @@ def test_dry_run_catchup_full(self):
 
         # Cleanup
         src_pg.stop()
+        dst_pg.stop()
+        self.del_test_dir(module_name, self.fname)
 
     def test_dry_run_catchup_ptrack(self):
         """
-        Test dry-run option for catchup in incremental mode
+        Test dry-run option for catchup in incremental ptrack mode
         """
         if not self.ptrack:
             return unittest.skip('Skipped because ptrack support is disabled')
@@ -1514,6 +1521,10 @@ def test_dry_run_catchup_ptrack(self):
         src_pg.safe_psql(
             "postgres",
             "CREATE TABLE ultimate_question(answer int)")
+        src_pg.pgbench_init(scale = 10)
+        pgbench = src_pg.pgbench(options=['-T', '10', '--no-vacuum'])
+        pgbench.wait()
+        src_pg.safe_psql("postgres", "INSERT INTO ultimate_question VALUES(42)")
 
         # preparation 2: make clean shutdowned lagging behind replica
         dst_pg = self.make_empty_node(os.path.join(module_name, self.fname, 'dst'))
@@ -1549,4 +1560,63 @@ def test_dry_run_catchup_ptrack(self):
 
         # Cleanup
         src_pg.stop()
+        dst_pg.stop()
+        self.del_test_dir(module_name, self.fname)
+
+    def test_dry_run_catchup_delta(self):
+        """
+        Test dry-run option for catchup in incremental delta mode
+        """
+
+        # preparation 1: source
+        src_pg = self.make_simple_node(
+            base_dir = os.path.join(module_name, self.fname, 'src'),
+            set_replication = True,
+            pg_options = { 'wal_log_hints': 'on' }
+            )
+        src_pg.slow_start()
+        src_pg.safe_psql(
+            "postgres",
+            "CREATE TABLE ultimate_question(answer int)")
+        src_pg.pgbench_init(scale = 10)
+        pgbench = src_pg.pgbench(options=['-T', '10', '--no-vacuum'])
+        pgbench.wait()
+        src_pg.safe_psql("postgres", "INSERT INTO ultimate_question VALUES(42)")
+
+        # preparation 2: make clean shutdowned lagging behind replica
+        dst_pg = self.make_empty_node(os.path.join(module_name, self.fname, 'dst'))
+        self.catchup_node(
+            backup_mode = 'FULL',
+            source_pgdata = src_pg.data_dir,
+            destination_node = dst_pg,
+            options = ['-d', 'postgres', '-p', str(src_pg.port), '--stream']
+            )
+        self.set_replica(src_pg, dst_pg)
+        dst_options = {}
+        dst_options['port'] = str(dst_pg.port)
+        self.set_auto_conf(dst_pg, dst_options)
+        dst_pg.slow_start(replica = True)
+        dst_pg.stop()
+
+        # save the condition before dry-run
+        content_before = self.pgdata_content(dst_pg.data_dir)
+
+        # do incremental catchup
+        self.catchup_node(
+            backup_mode = 'DELTA',
+            source_pgdata = src_pg.data_dir,
+            destination_node = dst_pg,
+            options = ['-d', 'postgres', '-p', str(src_pg.port), '--stream', '--dry-run']
+            )
+
+        # compare data dirs before and after cathup
+        self.compare_pgdata(
+            content_before,
+            self.pgdata_content(dst_pg.data_dir)
+            )
+
+        # Cleanup
+        src_pg.stop()
+        dst_pg.stop()
+        self.del_test_dir(module_name, self.fname)