type MockCallSource = { mock: { calls: Array<Array<unknown>> } };

function firstMockArg(source: MockCallSource, label: string, argIndex = 0) {

const arg = source.mock.calls[0]?.[argIndex];

const [call] = source.mock.calls;

if (!call) {

throw new Error(`expected ${label} call`);

}

const arg = call[argIndex];

if (arg === undefined) {

throw new Error(`expected ${label} arg`);

}

}

function firstAddedMemory(add: ReturnType<typeof vi.fn>) {

const batch = add.mock.calls[0]?.[0] as Array<Record<string, unknown>> | undefined;

const batch = firstMockArg(add as MockCallSource, "memory add") as

| Array<Record<string, unknown>>

| undefined;

const memory = batch?.[0];

if (!memory) {

throw new Error("expected first added memory");