diff --git a/quc/test/runs.test.js b/quc/test/runs.test.js
new file mode 100644
index 0000000..3250f5a
--- /dev/null
+++ b/quc/test/runs.test.js
@@ -0,0 +1,51 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { createRun, setStatus, addEvent, getRun, getEvents } from "../src/runs.js";
+
+const mem = () => { const m = new Map(); return { get: async (k) => m.get(k) ?? null, put: async (k, v) => void m.set(k, v), delete: async (k) => void m.delete(k) }; };
+const input = (visitor = "v1") => ({ repo: "https://github.com/a/b", task: "Fix the flaky date test", visitor });
+const code = (p) => p.then(() => null, (e) => e.code);
+
+test("a run walks queued -> running -> ended and persists in the store", async () => {
+  const s = mem();
+  const run = await createRun(s, input());
+  assert.equal(run.status, "queued");
+  assert.equal((await setStatus(s, run.id, "running")).status, "running");
+  const done = await setStatus(s, run.id, "ended", "finished");
+  assert.deepEqual([done.status, done.outcome], ["ended", "finished"]);
+  assert.ok(done.startedAt && done.endedAt);
+  assert.deepEqual(await getRun(s, run.id), done);
+});
+
+test("bad transitions, outcomes and inputs are refused", async () => {
+  const s = mem();
+  const { id } = await createRun(s, input());
+  assert.equal(await code(setStatus(s, id, "ended")), "outcome");
+  assert.equal(await code(setStatus(s, id, "queued")), "transition");
+  await setStatus(s, id, "ended", "safeworded");
+  assert.equal(await code(setStatus(s, id, "running")), "transition");
+  assert.equal(await code(setStatus(s, "nope", "running")), "not_found");
+  assert.equal(await code(createRun(s, { ...input(), repo: "x" })), "invalid");
+  assert.equal(await code(createRun(s, input(""))), "visitor");
+});
+
+test("one active run per visitor; ending frees the slot; other visitors are unaffected", async () => {
+  const s = mem();
+  const a = await createRun(s, input("v1"));
+  assert.equal(await code(createRun(s, input("v1"))), "active");
+  await setStatus(s, a.id, "running");
+  assert.equal(await code(createRun(s, input("v1"))), "active");
+  await createRun(s, input("v2"));
+  await setStatus(s, a.id, "ended", "unlocked");
+  await createRun(s, input("v1"));
+});
+
+test("events append in order and unknown kinds are refused", async () => {
+  const s = mem();
+  const { id } = await createRun(s, input());
+  await addEvent(s, id, "commentary", "reading the tests");
+  await addEvent(s, id, "diff", "--- a\n+++ b");
+  assert.deepEqual((await getEvents(s, id)).map((e) => [e.seq, e.kind]), [[1, "commentary"], [2, "diff"]]);
+  assert.equal(await code(addEvent(s, id, "nope", "")), "kind");
+  assert.equal(await code(addEvent(s, "nope", "commit", "")), "not_found");
+});