update test cases

Signed-off-by: Arham-Nasir <arqamnasir719@gmail.com>

tests/hostcfgd/hostcfgd_test.py

@@ -896,4 +896,88 @@ def test_handler_functionality(self):
              mock.patch('hostcfgd.syslog.syslog') as mock_syslog:
             daemon.memory_statistics_handler('enabled', None, 'true')
             mock_syslog.assert_any_call(mock.ANY, 
-                "MemoryStatisticsCfg: Error while handling memory statistics update: Handler error")
+                "MemoryStatisticsCfg: Error while handling memory statistics update: Handler error")
+
+    def test_apply_setting_functionality(self):
+        """Test apply_setting method scenarios"""
+        # Test restart case when enabled is true
+        with mock.patch.object(self.mem_stat_cfg, 'restart_memory_statistics') as mock_restart, \
+            mock.patch.object(self.mem_stat_cfg, 'shutdown_memory_statistics') as mock_shutdown, \
+            mock.patch.object(self.mem_stat_cfg, 'reload_memory_statistics') as mock_reload:
+            self.mem_stat_cfg.cache['enabled'] = 'true'
+            self.mem_stat_cfg.apply_setting('sampling_interval', '10')
+            mock_restart.assert_called_once()
+            mock_shutdown.assert_not_called()
+            mock_reload.assert_not_called()
+
+        # Test shutdown case when enabled is false
+        with mock.patch.object(self.mem_stat_cfg, 'restart_memory_statistics') as mock_restart, \
+            mock.patch.object(self.mem_stat_cfg, 'shutdown_memory_statistics') as mock_shutdown, \
+            mock.patch.object(self.mem_stat_cfg, 'reload_memory_statistics') as mock_reload:
+            self.mem_stat_cfg.cache['enabled'] = 'false'
+            self.mem_stat_cfg.apply_setting('enabled', 'false')
+            mock_shutdown.assert_called_once()
+            mock_restart.assert_not_called()
+            mock_reload.assert_not_called()
+
+        # Test reload case for other settings when enabled
+        with mock.patch.object(self.mem_stat_cfg, 'restart_memory_statistics') as mock_restart, \
+            mock.patch.object(self.mem_stat_cfg, 'shutdown_memory_statistics') as mock_shutdown, \
+            mock.patch.object(self.mem_stat_cfg, 'reload_memory_statistics') as mock_reload:
+            self.mem_stat_cfg.cache['enabled'] = 'true'
+            self.mem_stat_cfg.apply_setting('retention_period', '20')
+            mock_reload.assert_called_once()
+            mock_restart.assert_not_called()
+            mock_shutdown.assert_not_called()
+
+        # Test exception handling
+        with mock.patch.object(self.mem_stat_cfg, 'reload_memory_statistics', 
+                            side_effect=Exception("Test error")), \
+            mock.patch('hostcfgd.syslog.syslog') as mock_syslog:
+            self.mem_stat_cfg.apply_setting('retention_period', '20')
+            mock_syslog.assert_any_call(mock.ANY, 
+                "MemoryStatisticsCfg: Exception in apply_setting() for key 'retention_period': Test error")
+
+    def test_reload_memory_statistics_error(self):
+        """Test error handling in reload_memory_statistics"""
+        with mock.patch.object(self.mem_stat_cfg, 'get_memory_statistics_pid', return_value=123), \
+            mock.patch('hostcfgd.os.kill', side_effect=Exception("Reload failed")), \
+            mock.patch('hostcfgd.syslog.syslog') as mock_syslog:
+            self.mem_stat_cfg.reload_memory_statistics()
+            mock_syslog.assert_any_call(mock.ANY, 
+                "MemoryStatisticsCfg: Failed to reload MemoryStatisticsDaemon: Reload failed")
+
+    def test_shutdown_memory_statistics_error(self):
+        """Test error handling in shutdown_memory_statistics"""
+        with mock.patch.object(self.mem_stat_cfg, 'get_memory_statistics_pid', return_value=123), \
+            mock.patch('hostcfgd.os.kill', side_effect=Exception("Shutdown failed")), \
+            mock.patch('hostcfgd.syslog.syslog') as mock_syslog:
+            self.mem_stat_cfg.shutdown_memory_statistics()
+            mock_syslog.assert_any_call(mock.ANY, 
+                "MemoryStatisticsCfg: Failed to shutdown MemoryStatisticsDaemon: Shutdown failed")
+
+    def test_wait_for_shutdown_general_error(self):
+        """Test general exception handling in wait_for_shutdown"""
+        with mock.patch('hostcfgd.psutil.Process', side_effect=Exception("Unexpected error")), \
+            mock.patch('hostcfgd.syslog.syslog') as mock_syslog:
+            self.mem_stat_cfg.wait_for_shutdown(123)
+            mock_syslog.assert_any_call(mock.ANY, 
+                "MemoryStatisticsCfg: Exception in wait_for_shutdown(): Unexpected error")
+
+    def test_get_memory_statistics_pid_additional_scenarios(self):
+        """Test additional scenarios for get_memory_statistics_pid"""
+        # Test non-existent PID
+        with mock.patch('builtins.open', mock.mock_open(read_data="123")), \
+            mock.patch('hostcfgd.psutil.pid_exists', return_value=False), \
+            mock.patch('hostcfgd.syslog.syslog') as mock_syslog:
+            pid = self.mem_stat_cfg.get_memory_statistics_pid()
+            self.assertIsNone(pid)
+            mock_syslog.assert_any_call(mock.ANY, "MemoryStatisticsCfg: PID does not exist.")
+
+        # Test general exception
+        with mock.patch('builtins.open', side_effect=Exception("Unexpected error")), \
+            mock.patch('hostcfgd.syslog.syslog') as mock_syslog:
+            pid = self.mem_stat_cfg.get_memory_statistics_pid()
+            self.assertIsNone(pid)
+            mock_syslog.assert_any_call(mock.ANY, 
+                "MemoryStatisticsCfg: Exception failed to retrieve MemoryStatisticsDaemon PID: Unexpected error")