test(FN-4789): add initial master key manager tests

Fusion-Task-Id: FN-4789
Fusion-Task-Lineage: cef0d12e-556e-43d8-9ce0-e4962c2d091b

packages/core/src/__tests__/master-key.test.ts

@@ -0,0 +1,75 @@
+import { afterEach, describe, expect, it } from "vitest";
+import { mkdtempSync } from "node:fs";
+import { stat, rm } from "node:fs/promises";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+import { MasterKeyManager, MASTER_KEY_FILENAME, type KeytarLike } from "../master-key.js";
+
+function createTempDir(): string {
+  return mkdtempSync(join(tmpdir(), "fn-master-key-test-"));
+}
+
+function createKeytarStub(initial?: string): KeytarLike {
+  let value = initial ?? null;
+  return {
+    async getPassword() {
+      return value;
+    },
+    async setPassword(_service, _account, password) {
+      value = password;
+    },
+    async deletePassword() {
+      value = null;
+      return true;
+    },
+  };
+}
+
+describe("MasterKeyManager", () => {
+  const tempDirs: string[] = [];
+
+  afterEach(async () => {
+    await Promise.all(tempDirs.map((dir) => rm(dir, { recursive: true, force: true })));
+    tempDirs.length = 0;
+  });
+
+  it("creates and reuses a key in keychain backend", async () => {
+    const globalDir = createTempDir();
+    tempDirs.push(globalDir);
+    const manager = new MasterKeyManager({ globalDir, keytarModule: createKeytarStub() });
+
+    const first = await manager.getOrCreateKey();
+    const second = await manager.getOrCreateKey();
+
+    expect(first.byteLength).toBe(32);
+    expect(second.equals(first)).toBe(true);
+    expect(await manager.getBackend()).toBe("keychain");
+  });
+
+  it("falls back to file backend when keychain is unavailable", async () => {
+    const globalDir = createTempDir();
+    tempDirs.push(globalDir);
+    const manager = new MasterKeyManager({
+      globalDir,
+      keytarModule: {
+        getPassword: async () => {
+          throw new Error("keychain unavailable");
+        },
+        setPassword: async () => {
+          throw new Error("keychain unavailable");
+        },
+        deletePassword: async () => {
+          throw new Error("keychain unavailable");
+        },
+      },
+    });
+
+    const key = await manager.getOrCreateKey();
+    const fileStat = await stat(join(globalDir, MASTER_KEY_FILENAME));
+
+    expect(key.byteLength).toBe(32);
+    expect(await manager.getBackend()).toBe("file");
+    expect(fileStat.size).toBe(32);
+    expect(fileStat.mode & 0o777).toBe(0o600);
+  });
+});