From 1453a00b9ca7849b3da82eff24b60e97079e960f Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Thu, 29 Oct 2026 00:12:48 +0100
Subject: [PATCH] fix: verify-references installs TS deps; sync-check covers
 expansion tests; template gitignore and passWithNoTests

verify-references ran a bare `npx vitest run` in the staged reference, which
fetched an unrelated vitest that could not load the reference config. It now
installs the reference's devDependencies first. sync-check also checks each
module's expansion/tests against ### headings in expansion/README.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 course/00-rewrite-trap/lesson.md              |  4 ++--
 tools/lib.mjs                                 |  6 ++---
 tools/sync-check.mjs                          | 23 ++++++++++++-------
 .../course-bad/01-a/expansion/README.md       |  1 +
 .../course-bad/01-a/expansion/tests/rust/c.rs |  2 ++
 .../course/01-m01/expansion/README.md         |  3 +++
 .../01-m01/expansion/tests/rust/m01x.rs       |  2 ++
 .../01-m01/expansion/tests/ts/m01x.test.ts    |  2 ++
 tools/test/sync-check.test.mjs                |  6 +++++
 tools/test/verify-references.test.mjs         | 10 ++++++++
 tools/verify-references.mjs                   | 14 +++++++----
 workspace-template/rust/.gitignore            |  1 +
 workspace-template/ts/.gitignore              |  1 +
 workspace-template/ts/vitest.config.ts        |  2 +-
 14 files changed, 59 insertions(+), 18 deletions(-)
 create mode 100644 tools/test/fixtures/course-bad/01-a/expansion/README.md
 create mode 100644 tools/test/fixtures/course-bad/01-a/expansion/tests/rust/c.rs
 create mode 100644 tools/test/fixtures/course/01-m01/expansion/README.md
 create mode 100644 tools/test/fixtures/course/01-m01/expansion/tests/rust/m01x.rs
 create mode 100644 tools/test/fixtures/course/01-m01/expansion/tests/ts/m01x.test.ts
 create mode 100644 workspace-template/rust/.gitignore
 create mode 100644 workspace-template/ts/.gitignore

diff --git a/course/00-rewrite-trap/lesson.md b/course/00-rewrite-trap/lesson.md
index 13f4a30..8636625 100644
--- a/course/00-rewrite-trap/lesson.md
+++ b/course/00-rewrite-trap/lesson.md
@@ -244,10 +244,10 @@ cp -r workspace-template/ts ~/my-engine
 cd ~/my-engine
 git init && git add -A && git commit -m "start from template"
 npm install
-npm test -- --passWithNoTests
+npm test
 ```
 
-Copy the whole directory with `cp -r` so the hidden `.course.json` file (which records your track) comes along. With no tests yet, `cargo test` reports 0 tests, and `npm test` needs `--passWithNoTests` to exit cleanly.
+Copy the whole directory with `cp -r` so the hidden `.course.json` file (which records your track) comes along. With no tests yet, both `cargo test` and `npm test` report 0 tests and exit cleanly.
 
 **Read the template's README.** Your engine goes in `src/engine/`, your cards in `src/content/`, and `src/harness` is the thin adapter the course's tests call.
 
diff --git a/tools/lib.mjs b/tools/lib.mjs
index a8ff1c3..cb47d6c 100644
--- a/tools/lib.mjs
+++ b/tools/lib.mjs
@@ -39,9 +39,9 @@ export function testNames(path, lang) {
   return [...names].sort();
 }
 
-/** `### test_…` headings in a module's scenarios.md. */
-export function scenarioNames(path) {
-  const f = join(path, "scenarios.md");
+/** `### test_…` headings in a module's scenarios.md (or another file in `path`). */
+export function scenarioNames(path, file = "scenarios.md") {
+  const f = join(path, file);
   if (!existsSync(f)) return [];
   const names = new Set();
   for (const m of readFileSync(f, "utf8").matchAll(/^### (test_\w+)/gm)) names.add(m[1]);
diff --git a/tools/sync-check.mjs b/tools/sync-check.mjs
index 02f0566..bfee577 100644
--- a/tools/sync-check.mjs
+++ b/tools/sync-check.mjs
@@ -1,24 +1,31 @@
 #!/usr/bin/env node
 // Verifies Rust tests, TS tests and scenarios.md list identical test names per module.
+// A module's Expansion Drop (expansion/tests/{rust,ts}, scenarios as `### test_…`
+// headings in expansion/README.md) is checked the same way, as a separate set.
+import { join } from "node:path";
 import { moduleDirs, testNames, scenarioNames } from "./lib.mjs";
 
 const problems = [];
-for (const mod of moduleDirs()) {
+function check(label, path, scenarioFile) {
   const sets = {
-    rust: testNames(mod.path, "rust"),
-    ts: testNames(mod.path, "ts"),
-    scenarios: scenarioNames(mod.path),
+    rust: testNames(path, "rust"),
+    ts: testNames(path, "ts"),
+    scenarios: scenarioNames(path, scenarioFile),
   };
-  if (Object.values(sets).every((s) => s.length === 0)) continue;
+  if (Object.values(sets).every((s) => s.length === 0)) return;
   const all = new Set(Object.values(sets).flat());
   for (const name of [...all].sort()) {
     for (const [where, names] of Object.entries(sets)) {
-      if (!names.includes(name)) {
-        problems.push(`module ${mod.num}-${mod.slug}: ${name} missing from ${where}`);
-      }
+      if (!names.includes(name)) problems.push(`${label}: ${name} missing from ${where}`);
     }
   }
 }
+
+for (const mod of moduleDirs()) {
+  const label = `module ${mod.num}-${mod.slug}`;
+  check(label, mod.path, "scenarios.md");
+  check(`${label} expansion`, join(mod.path, "expansion"), "README.md");
+}
 if (problems.length) {
   console.error("sync-check: mismatches\n" + problems.map((p) => "  " + p).join("\n"));
   process.exit(1);
diff --git a/tools/test/fixtures/course-bad/01-a/expansion/README.md b/tools/test/fixtures/course-bad/01-a/expansion/README.md
new file mode 100644
index 0000000..935cb90
--- /dev/null
+++ b/tools/test/fixtures/course-bad/01-a/expansion/README.md
@@ -0,0 +1 @@
+# Expansion
diff --git a/tools/test/fixtures/course-bad/01-a/expansion/tests/rust/c.rs b/tools/test/fixtures/course-bad/01-a/expansion/tests/rust/c.rs
new file mode 100644
index 0000000..4717094
--- /dev/null
+++ b/tools/test/fixtures/course-bad/01-a/expansion/tests/rust/c.rs
@@ -0,0 +1,2 @@
+#[test]
+fn test_01x_c() {}
diff --git a/tools/test/fixtures/course/01-m01/expansion/README.md b/tools/test/fixtures/course/01-m01/expansion/README.md
new file mode 100644
index 0000000..0165f5b
--- /dev/null
+++ b/tools/test/fixtures/course/01-m01/expansion/README.md
@@ -0,0 +1,3 @@
+# Expansion
+
+### test_01x_a
diff --git a/tools/test/fixtures/course/01-m01/expansion/tests/rust/m01x.rs b/tools/test/fixtures/course/01-m01/expansion/tests/rust/m01x.rs
new file mode 100644
index 0000000..7936295
--- /dev/null
+++ b/tools/test/fixtures/course/01-m01/expansion/tests/rust/m01x.rs
@@ -0,0 +1,2 @@
+#[test]
+fn test_01x_a() {}
diff --git a/tools/test/fixtures/course/01-m01/expansion/tests/ts/m01x.test.ts b/tools/test/fixtures/course/01-m01/expansion/tests/ts/m01x.test.ts
new file mode 100644
index 0000000..51f5ae0
--- /dev/null
+++ b/tools/test/fixtures/course/01-m01/expansion/tests/ts/m01x.test.ts
@@ -0,0 +1,2 @@
+import { test } from "vitest";
+test("test_01x_a", () => {});
diff --git a/tools/test/sync-check.test.mjs b/tools/test/sync-check.test.mjs
index 9c478f3..e0548b5 100644
--- a/tools/test/sync-check.test.mjs
+++ b/tools/test/sync-check.test.mjs
@@ -14,3 +14,9 @@ test("sync_passes_consistent_course", () => {
   const r = run("sync-check.mjs", [], { COURSE_ROOT: join(fixtures, "course") });
   assert.equal(r.code, 0, r.out);
 });
+
+test("sync_checks_expansion_tests_against_readme", () => {
+  const r = run("sync-check.mjs", [], { COURSE_ROOT: join(fixtures, "course-bad") });
+  assert.match(r.out, /01-a expansion: test_01x_c missing from ts/);
+  assert.match(r.out, /01-a expansion: test_01x_c missing from scenarios/);
+});
diff --git a/tools/test/verify-references.test.mjs b/tools/test/verify-references.test.mjs
index dcf89a1..854dd4f 100644
--- a/tools/test/verify-references.test.mjs
+++ b/tools/test/verify-references.test.mjs
@@ -45,3 +45,13 @@ test("verify_stage_copies_all_earlier_module_tests", async () => {
   for (const f of ["m01.rs", "m02.rs", "m03.rs"]) assert.ok(existsSync(join(dir, "tests", f)));
   assert.ok(existsSync(join(dir, "Cargo.toml")));
 });
+
+test("verify_ts_default_installs_dependencies_first", async () => {
+  // A staged reference has no node_modules; a bare `npx vitest` fetches the
+  // latest vitest, which cannot load the reference's vitest.config.ts.
+  const { commandFor } = await import("../verify-references.mjs");
+  const cmd = commandFor("ts", {});
+  assert.match(cmd, /^npm (ci|install)\b.*&& npx vitest run$/);
+  assert.equal(commandFor("ts", { VERIFY_CMD_TS: "true" }), "true");
+  assert.equal(commandFor("rust", {}), "cargo test");
+});
diff --git a/tools/verify-references.mjs b/tools/verify-references.mjs
index 402a712..3c8288f 100644
--- a/tools/verify-references.mjs
+++ b/tools/verify-references.mjs
@@ -6,11 +6,17 @@ import { tmpdir } from "node:os";
 import { basename, join } from "node:path";
 import { moduleDirs, testFiles, fail } from "./lib.mjs";
 
-const COMMANDS = {
-  rust: () => process.env.VERIFY_CMD_RUST || "cargo test",
-  ts: () => process.env.VERIFY_CMD_TS || "npx vitest run",
+// A staged reference has no node_modules, so TS installs the reference's own
+// pinned devDependencies first (a bare `npx vitest` would fetch an unrelated version).
+const DEFAULTS = {
+  rust: "cargo test",
+  ts: "npm install --no-audit --no-fund --loglevel=error && npx vitest run",
 };
 
+export function commandFor(lang, env = process.env) {
+  return env[`VERIFY_CMD_${lang.toUpperCase()}`] || DEFAULTS[lang];
+}
+
 export function planVerification(mods, upTo) {
   return mods
     .filter((m) => Number(m.num) >= 1 && Number(m.num) <= upTo)
@@ -41,7 +47,7 @@ if (import.meta.main) {
   for (const p of plans) {
     for (const lang of p.langs) {
       const dir = stage(p, lang);
-      const r = spawnSync(COMMANDS[lang](), { cwd: dir, shell: true, encoding: "utf8" });
+      const r = spawnSync(commandFor(lang), { cwd: dir, shell: true, encoding: "utf8" });
       const ok = r.status === 0;
       failed ||= !ok;
       console.log(`module ${p.num}-${p.slug} [${lang}]: ${ok ? "ok" : "FAIL"}`);
diff --git a/workspace-template/rust/.gitignore b/workspace-template/rust/.gitignore
new file mode 100644
index 0000000..2f7896d
--- /dev/null
+++ b/workspace-template/rust/.gitignore
@@ -0,0 +1 @@
+target/
diff --git a/workspace-template/ts/.gitignore b/workspace-template/ts/.gitignore
new file mode 100644
index 0000000..c2658d7
--- /dev/null
+++ b/workspace-template/ts/.gitignore
@@ -0,0 +1 @@
+node_modules/
diff --git a/workspace-template/ts/vitest.config.ts b/workspace-template/ts/vitest.config.ts
index 00988cf..a6f65eb 100644
--- a/workspace-template/ts/vitest.config.ts
+++ b/workspace-template/ts/vitest.config.ts
@@ -1,5 +1,5 @@
 import { defineConfig } from "vitest/config";
 
 export default defineConfig({
-  test: { include: ["tests/**/*.test.ts"] },
+  test: { include: ["tests/**/*.test.ts"], passWithNoTests: true },
 });