test: add Phase 4 database integration tests (partial)

- Add comprehensive test utilities for database testing
- Implement connection management tests for in-memory and file databases
- Add transaction tests including nested transactions and savepoints
- Test database lifecycle, error handling, and performance
- Include tests for WAL mode, connection pooling, and constraints

Part of Phase 4: Integration Testing

tests/mocks/n8n-api/data/executions.ts

@@ -0,0 +1,159 @@
+/**
+ * Mock execution data for MSW handlers
+ */
+
+export interface MockExecution {
+  id: string;
+  workflowId: string;
+  status: 'success' | 'error' | 'waiting' | 'running';
+  mode: 'manual' | 'trigger' | 'webhook' | 'internal';
+  startedAt: string;
+  stoppedAt?: string;
+  data?: any;
+  error?: any;
+}
+
+export const mockExecutions: MockExecution[] = [
+  {
+    id: 'exec_1',
+    workflowId: 'workflow_1',
+    status: 'success',
+    mode: 'manual',
+    startedAt: '2024-01-01T10:00:00.000Z',
+    stoppedAt: '2024-01-01T10:00:05.000Z',
+    data: {
+      resultData: {
+        runData: {
+          'node_2': [
+            {
+              startTime: 1704106800000,
+              executionTime: 234,
+              data: {
+                main: [[{
+                  json: {
+                    status: 200,
+                    data: { message: 'Success' }
+                  }
+                }]]
+              }
+            }
+          ]
+        }
+      }
+    }
+  },
+  {
+    id: 'exec_2',
+    workflowId: 'workflow_2',
+    status: 'error',
+    mode: 'webhook',
+    startedAt: '2024-01-01T11:00:00.000Z',
+    stoppedAt: '2024-01-01T11:00:02.000Z',
+    error: {
+      message: 'Could not send message to Slack',
+      stack: 'Error: Could not send message to Slack\n    at SlackNode.execute',
+      node: 'slack_1'
+    },
+    data: {
+      resultData: {
+        runData: {
+          'webhook_1': [
+            {
+              startTime: 1704110400000,
+              executionTime: 10,
+              data: {
+                main: [[{
+                  json: {
+                    headers: { 'content-type': 'application/json' },
+                    body: { message: 'Test webhook' }
+                  }
+                }]]
+              }
+            }
+          ]
+        }
+      }
+    }
+  },
+  {
+    id: 'exec_3',
+    workflowId: 'workflow_3',
+    status: 'waiting',
+    mode: 'trigger',
+    startedAt: '2024-01-01T12:00:00.000Z',
+    data: {
+      resultData: {
+        runData: {}
+      },
+      waitingExecutions: {
+        'agent_1': {
+          reason: 'Waiting for user input'
+        }
+      }
+    }
+  }
+];
+
+/**
+ * Factory functions for creating mock executions
+ */
+export const executionFactory = {
+  /**
+   * Create a successful execution
+   */
+  success: (workflowId: string, data?: any): MockExecution => ({
+    id: `exec_${Date.now()}`,
+    workflowId,
+    status: 'success',
+    mode: 'manual',
+    startedAt: new Date().toISOString(),
+    stoppedAt: new Date(Date.now() + 5000).toISOString(),
+    data: data || {
+      resultData: {
+        runData: {
+          'node_1': [{
+            startTime: Date.now(),
+            executionTime: 100,
+            data: {
+              main: [[{ json: { success: true } }]]
+            }
+          }]
+        }
+      }
+    }
+  }),
+
+  /**
+   * Create a failed execution
+   */
+  error: (workflowId: string, error: { message: string; node?: string }): MockExecution => ({
+    id: `exec_${Date.now()}`,
+    workflowId,
+    status: 'error',
+    mode: 'manual',
+    startedAt: new Date().toISOString(),
+    stoppedAt: new Date(Date.now() + 2000).toISOString(),
+    error: {
+      message: error.message,
+      stack: `Error: ${error.message}\n    at Node.execute`,
+      node: error.node
+    },
+    data: {
+      resultData: {
+        runData: {}
+      }
+    }
+  }),
+
+  /**
+   * Create a custom execution
+   */
+  custom: (config: Partial<MockExecution>): MockExecution => ({
+    id: `exec_${Date.now()}`,
+    workflowId: 'workflow_1',
+    status: 'success',
+    mode: 'manual',
+    startedAt: new Date().toISOString(),
+    ...config
+  })
+};