[#258] Problems in ProbackupTest and TestBasic(ProbackupTest) are fixed (#259)

* [#258] Declaration of ProbackupTest::pg_node is corrected

ProbackupTest::pg_node is testgres.NodeApp, not testgres.PostgresNode.

Asserts are added.

* [#258] TestBasic::test_full_backup cleans node object

Node cleanup is added.

TODO: we should to stop node only and cleanup his data in conftest.

Author: dmitry-lipetsk

testgres/plugins/pg_probackup2/pg_probackup2/tests/test_basic.py

@@ -11,7 +11,7 @@
 
 
 class ProbackupTest:
-    pg_node: testgres.PostgresNode
+    pg_node: testgres.NodeApp
 
     @staticmethod
     def probackup_is_available() -> bool:
@@ -75,21 +75,30 @@ def helper__build_backup_dir(self, backup='backup'):
 @pytest.mark.skipif(not ProbackupTest.probackup_is_available(), reason="Check that PGPROBACKUPBIN is defined and is valid.")
 class TestBasic(ProbackupTest):
     def test_full_backup(self):
+        assert self.pg_node is not None
+        assert type(self.pg_node) == testgres.NodeApp  # noqa: E721
+        assert self.pb is not None
+        assert type(self.pb) == ProbackupApp  # noqa: E721
+
         # Setting up a simple test node
         node = self.pg_node.make_simple('node', pg_options={"fsync": "off", "synchronous_commit": "off"})
 
-        # Initialize and configure Probackup
-        self.pb.init()
-        self.pb.add_instance('node', node)
-        self.pb.set_archiving('node', node)
+        assert node is not None
+        assert type(node) == testgres.PostgresNode  # noqa: E721
+
+        with node:
+            # Initialize and configure Probackup
+            self.pb.init()
+            self.pb.add_instance('node', node)
+            self.pb.set_archiving('node', node)
 
-        # Start the node and initialize pgbench
-        node.slow_start()
-        node.pgbench_init(scale=100, no_vacuum=True)
+            # Start the node and initialize pgbench
+            node.slow_start()
+            node.pgbench_init(scale=100, no_vacuum=True)
 
-        # Perform backup and validation
-        backup_id = self.pb.backup_node('node', node)
-        out = self.pb.validate('node', backup_id)
+            # Perform backup and validation
+            backup_id = self.pb.backup_node('node', node)
+            out = self.pb.validate('node', backup_id)
 
-        # Check if the backup is valid
-        assert f"INFO: Backup {backup_id} is valid" in out
+            # Check if the backup is valid
+            assert f"INFO: Backup {backup_id} is valid" in out