test(cli): add update diagnostics regression test

src/tests/update-cmd-diagnostics.test.ts

@@ -0,0 +1,27 @@
+/**
+ * Regression test for #3445: gsd update must print both current and latest
+ * versions for diagnostics, and bypass npm cache.
+ */
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { join, dirname } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+test("update-cmd prints latest version before comparison (#3445)", () => {
+  const src = readFileSync(join(__dirname, "..", "update-cmd.ts"), "utf-8");
+  const latestPrintIdx = src.indexOf("Latest version:");
+  const comparisonIdx = src.indexOf("compareSemver(latest, current)");
+  assert.ok(latestPrintIdx !== -1, "Must print latest version");
+  assert.ok(latestPrintIdx < comparisonIdx, "Must print latest BEFORE comparison");
+});
+
+test("update-cmd bypasses npm cache (#3445)", () => {
+  const src = readFileSync(join(__dirname, "..", "update-cmd.ts"), "utf-8");
+  assert.ok(
+    src.includes("npm_config_cache"),
+    "Must clear npm cache env to bypass stale registry data",
+  );
+});