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+// Regression tests for peer simulation seeding in the student-facing
+// challenge progression script. Challenges 1-13 reference a seeded
+// "Peer Simulation: Welcome Link Needs Context" issue and a
+// "Peer Simulation: Improve contribution guidance" pull request. These were
+// originally created by scripts/classroom/Seed-PeerSimulation.ps1, which was
+// deleted with GitHub Classroom, leaving provisioned rooms without the
+// artifacts (support issue Community-Access/support#58, 2026-07-04). The
+// progression script must seed them idempotently on every run.
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const path = require('node:path');
+
+process.env.GITHUB_TOKEN = 'test-token';
+process.env.GITHUB_REPOSITORY = 'org/room';
+process.env.START_CHALLENGE = '';
+process.env.GITHUB_EVENT_NAME = '';
+process.env.CLOSED_ISSUE_TITLE = '';
+
+// The script resolves its issue-template directory from the working
+// directory, so requiring it must happen from inside learning-room/.
+process.chdir(path.join(__dirname, '..', '..', '..', 'learning-room'));
+
+const {
+  ensurePeerSimulationArtifacts,
+  ensureLabel,
+  ensurePeerSimulationBranch,
+  ensurePeerSimulationPullRequest
+} = require('../../../learning-room/.github/scripts/challenge-progression');
+
+function fakeRequest(overrides = {}) {
+  const calls = [];
+  const request = async (route, options = {}) => {
+    const method = options.method || 'GET';
+    calls.push({ method, route, body: options.body });
+    for (const [pattern, handler] of Object.entries(overrides)) {
+      const [overrideMethod, routePrefix] = pattern.split(' ');
+      if (method === overrideMethod && route.startsWith(routePrefix)) {
+        return handler({ route, options });
+      }
+    }
+    // Defaults that describe an empty, freshly provisioned room.
+    if (method === 'GET' && route.startsWith('/repos/org/room/issues?')) {
+      return [];
+    }
+    if (method === 'GET' && route.startsWith('/repos/org/room/pulls?')) {
+      return [];
+    }
+    if (method === 'GET' && route.startsWith('/repos/org/room/git/ref/heads/peer-simulation')) {
+      throw new Error('GET failed: 404 Not Found');
+    }
+    if (method === 'GET' && route.startsWith('/repos/org/room/git/ref/heads/main')) {
+      return { object: { sha: 'abc123' } };
+    }
+    if (method === 'GET' && route.startsWith('/repos/org/room/contents/')) {
+      throw new Error('GET failed: 404 Not Found');
+    }
+    if (method === 'POST' && route === '/repos/org/room/issues') {
+      return { number: 42, html_url: 'https://example.test/issue/42' };
+    }
+    if (method === 'POST' && route === '/repos/org/room/pulls') {
+      return { number: 7, html_url: 'https://example.test/pull/7' };
+    }
+    return null;
+  };
+  return { calls, request };
+}
+
+test('seeds labels, both issues, branch, file, and PR in an empty room', async () => {
+  const { calls, request } = fakeRequest();
+
+  await ensurePeerSimulationArtifacts(request);
+
+  const posts = calls.filter((c) => c.method === 'POST');
+  const labelPosts = posts.filter((c) => c.route === '/repos/org/room/labels');
+  assert.equal(labelPosts.length, 4);
+
+  const issuePosts = posts.filter((c) => c.route === '/repos/org/room/issues');
+  assert.deepEqual(
+    issuePosts.map((c) => c.body.title),
+    [
+      'Peer Simulation: Welcome Link Needs Context',
+      'Peer Simulation: Review Request for Contribution Guidance'
+    ]
+  );
+  assert.ok(issuePosts[0].body.labels.includes('peer-simulation'));
+
+  const refPosts = posts.filter((c) => c.route === '/repos/org/room/git/refs');
+  assert.equal(refPosts.length, 1);
+  assert.equal(refPosts[0].body.ref, 'refs/heads/peer-simulation/review-pr');
+  assert.equal(refPosts[0].body.sha, 'abc123');
+
+  const filePuts = calls.filter((c) => c.method === 'PUT');
+  assert.equal(filePuts.length, 1);
+  assert.ok(filePuts[0].route.includes('docs/samples/peer-review-practice.md'));
+  assert.equal(filePuts[0].body.branch, 'peer-simulation/review-pr');
+
+  const prPosts = posts.filter((c) => c.route === '/repos/org/room/pulls');
+  assert.equal(prPosts.length, 1);
+  assert.equal(prPosts[0].body.title, 'Peer Simulation: Improve contribution guidance');
+  assert.equal(prPosts[0].body.head, 'peer-simulation/review-pr');
+  assert.equal(prPosts[0].body.base, 'main');
+  assert.match(prPosts[0].body.body, /#42/);
+});
+
+test('is idempotent: creates nothing when the artifacts already exist', async () => {
+  const { calls, request } = fakeRequest({
+    'GET /repos/org/room/issues?': () => [
+      { number: 5, title: 'Peer Simulation: Welcome Link Needs Context' },
+      { number: 6, title: 'Peer Simulation: Review Request for Contribution Guidance' }
+    ],
+    'GET /repos/org/room/git/ref/heads/peer-simulation': () => ({ object: { sha: 'abc123' } }),
+    'GET /repos/org/room/contents/': () => ({ sha: 'filesha' }),
+    'GET /repos/org/room/pulls?': () => [{ number: 7 }]
+  });
+
+  await ensurePeerSimulationArtifacts(request);
+
+  const writes = calls.filter(
+    (c) => (c.method === 'POST' || c.method === 'PUT') && c.route !== '/repos/org/room/labels'
+  );
+  assert.deepEqual(writes, []);
+});
+
+test('never throws: progression survives a seeding failure', async () => {
+  const request = async () => {
+    throw new Error('boom: no network');
+  };
+
+  await assert.doesNotReject(ensurePeerSimulationArtifacts(request));
+});
+
+test('ensureLabel tolerates a label that already exists', async () => {
+  const request = async () => {
+    throw new Error('POST /repos/org/room/labels failed: 422 already_exists');
+  };
+
+  await assert.doesNotReject(
+    ensureLabel({ name: 'peer-simulation', color: '5319e7', description: 'x' }, request)
+  );
+});
+
+test('branch seeding skips the commit when the practice file is present', async () => {
+  const { calls, request } = fakeRequest({
+    'GET /repos/org/room/git/ref/heads/peer-simulation': () => ({ object: { sha: 'abc123' } }),
+    'GET /repos/org/room/contents/': () => ({ sha: 'filesha' })
+  });
+
+  await ensurePeerSimulationBranch(request);
+
+  assert.deepEqual(calls.filter((c) => c.method !== 'GET'), []);
+});
+
+test('PR seeding skips creation when a PR for the branch exists in any state', async () => {
+  const { calls, request } = fakeRequest({
+    'GET /repos/org/room/pulls?': () => [{ number: 7, state: 'closed' }]
+  });
+
+  await ensurePeerSimulationPullRequest(6, request);
+
+  assert.deepEqual(calls.filter((c) => c.method === 'POST'), []);
+});