feat: Add testing framework and initial test cases for various tools and database operations

tests/helpers/database-helper.ts

@@ -0,0 +1,29 @@
+/**
+ * Database test helper - creates isolated database instances for testing
+ */
+
+import { database } from "../../src/storage/database.js";
+import { join } from "path";
+import { mkdirSync } from "fs";
+import type { TestContext } from "./test-utils.js";
+
+/**
+ * Setup test database with isolated data directory
+ */
+export function setupTestDatabase(testContext: TestContext): () => void {
+  const testDataDir = join(testContext.tempDir, "data");
+  mkdirSync(testDataDir, { recursive: true });
+
+  // Set environment variable for test data directory
+  const originalDataDir = process.env.MCP_TEST_DATA_DIR;
+  process.env.MCP_TEST_DATA_DIR = testDataDir;
+
+  // Return cleanup function
+  return () => {
+    if (originalDataDir) {
+      process.env.MCP_TEST_DATA_DIR = originalDataDir;
+    } else {
+      delete process.env.MCP_TEST_DATA_DIR;
+    }
+  };
+}