10 ways your app says “success” and does nothing

// before: `limit` is missing from the schema, so parse() silently removes it
const Update = z.object({ name: z.string() });
// after: list the field, and make unknown keys an error
const Update = z.object({ name: z.string(), limit: z.number().int().optional() }).strict();

// before: the API sends `expires_at`; this is undefined, so the column never changes
data: { title: input.title, expiresAt: input.expiresAt }
// after: map at the boundary, and test the write, not the status code
data: { title: input.title, expiresAt: input.expires_at }
expect((await getDoc(id)).expiresAt).toEqual(newDate);

// before: out of quota looks exactly like "checked, nothing found", and gets cached
if (!(await hasQuota(workspace))) return { flagged: false };
// after: a third state the caller can't mistake for a pass
if (!(await hasQuota(workspace))) return { status: "skipped", reason: "quota" } as const;

// before: limit 0 → no limit at all
if (opts.limit) query = query.limit(opts.limit);
// after
if (opts.limit !== undefined) query = query.limit(opts.limit);

// before: every selected person left the project, so this falls back to all members
const to = selected.length ? selected : allMembers;
// after: an empty selection fails closed
if (selected.length === 0) throw new Error("Choose recipients again");

// before: passes because no agent exists
it("never exports agents", async () => expect((await exportAll()).agents).toHaveLength(0));
// after: create one first, so the test proves the guard
it("never exports agents", async () => {
  await createAgent();
  expect((await exportAll()).agents).toHaveLength(0);
});

// before
const { data } = useQuery(detailsQuery(id));
if (!data) return <NotFound />;
// after
const { data, isPending } = useQuery(detailsQuery(id));
if (isPending) return <Spinner />;
if (!data) return <NotFound />;

// before: validation runs the same hooks as a real save, including the one that calls the payment provider
await runHooks("beforeChange", doc);
return { valid: true };
// after: hooks know it's a dry run, and uniqueness is checked, not assumed
await runHooks("beforeChange", doc, { dryRun: true });
await assertUniqueFields(doc);
return { valid: true };

// before: two rows selected, one activated, no error
await activate(selectedIds[0]);
// after: act on all of them, or hide the action for multi-select
await Promise.all(selectedIds.map(activate));

// before: the URL check sees "{{url}}" and strips it
return fill(sanitizeUrl(template.href), vars);
// after: fill first, then check what will actually be sent
return sanitizeUrl(fill(template.href, vars));