feat(generators): byte-identical snapshot machinery + realtime snapshot

turbo/generators/lib/snapshot.test.ts

@@ -0,0 +1,19 @@
+import { describe, it, expect } from "vitest";
+import { mkdtempSync, mkdirSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { computeSnapshot } from "./snapshot";
+
+describe("computeSnapshot", () => {
+  it("returns sorted file paths + sha256 hashes", () => {
+    const tmp = mkdtempSync(join(tmpdir(), "snapshot-"));
+    mkdirSync(join(tmp, "src"));
+    writeFileSync(join(tmp, "package.json"), `{ "name": "x" }\n`);
+    writeFileSync(join(tmp, "src", "index.ts"), `export {};\n`);
+    const snap = computeSnapshot(tmp);
+    expect(snap).toEqual([
+      { path: "package.json", sha256: expect.any(String) },
+      { path: "src/index.ts", sha256: expect.any(String) },
+    ]);
+  });
+});