test: add MCP backup test infrastructure and data utilities

Extend existing test data utilities with MCPBackupTestDataLoader for host-agnostic test configurations.

Changes:
- Add MCPBackupTestDataLoader class to test_data_utils.py
- Create host-agnostic test configuration templates (simple_server, complex_server, empty_config)
- Integrate with existing TestDataLoader hierarchy
- Support for dynamic test configuration generation

Test configurations are completely host-agnostic and validate backup system functionality without depending on specific host JSON structures.

Follows CrackingShells testing standards and integrates with existing Hatch test infrastructure.

Author: LittleCoinCoin

tests/test_data/configs/mcp_backup_test_configs/complex_server.json

@@ -0,0 +1,25 @@
+{
+  "servers": {
+    "server1": {
+      "command": "python",
+      "args": [
+        "server1.py"
+      ]
+    },
+    "server2": {
+      "command": "node",
+      "args": [
+        "server2.js"
+      ]
+    },
+    "server3": {
+      "command": "python",
+      "args": [
+        "server3.py"
+      ],
+      "env": {
+        "API_KEY": "test"
+      }
+    }
+  }
+}

tests/test_data/configs/mcp_backup_test_configs/simple_server.json

@@ -0,0 +1,10 @@
+{
+  "servers": {
+    "test_server": {
+      "command": "python",
+      "args": [
+        "server.py"
+      ]
+    }
+  }
+}

tests/test_data_utils.py

@@ -187,11 +187,60 @@ def get_logging_messages(self) -> Dict[str, str]:
         config = self.get_non_tty_config()
         return config["logging_messages"]
 
+class MCPBackupTestDataLoader(TestDataLoader):
+    """Specialized test data loader for MCP backup system tests."""
+
+    def __init__(self):
+        super().__init__()
+        self.mcp_backup_configs_dir = self.configs_dir / "mcp_backup_test_configs"
+        self.mcp_backup_configs_dir.mkdir(exist_ok=True)
+
+    def load_host_agnostic_config(self, config_type: str) -> Dict[str, Any]:
+        """Load host-agnostic test configuration.
+
+        Args:
+            config_type: Type of configuration to load
+
+        Returns:
+            Host-agnostic configuration dictionary
+        """
+        config_path = self.mcp_backup_configs_dir / f"{config_type}.json"
+        if not config_path.exists():
+            self._create_default_mcp_config(config_type)
+
+        with open(config_path, 'r') as f:
+            return json.load(f)
+
+    def _create_default_mcp_config(self, config_type: str):
+        """Create default host-agnostic MCP configuration."""
+        default_configs = {
+            "simple_server": {
+                "servers": {
+                    "test_server": {
+                        "command": "python",
+                        "args": ["server.py"]
+                    }
+                }
+            },
+            "complex_server": {
+                "servers": {
+                    "server1": {"command": "python", "args": ["server1.py"]},
+                    "server2": {"command": "node", "args": ["server2.js"]},
+                    "server3": {"command": "python", "args": ["server3.py"], "env": {"API_KEY": "test"}}
+                }
+            },
+            "empty_config": {"servers": {}}
+        }
+
+        config = default_configs.get(config_type, {"servers": {}})
+        config_path = self.mcp_backup_configs_dir / f"{config_type}.json"
+        with open(config_path, 'w') as f:
+            json.dump(config, f, indent=2)
+
 
 # Global instance for easy access
 test_data = TestDataLoader()
 
-
 # Convenience functions
 def load_test_config(config_name: str) -> Dict[str, Any]:
     """Load test configuration."""