Function returnsNext

testing/mock.ts:1732–1757

(
  values: Iterable<Return | Error>,
)

 * @return A function that returns the iterable values
 */
export function returnsNext<
  Return,
  // deno-lint-ignore no-explicit-any
  Self = any,
  // deno-lint-ignore no-explicit-any
  Args extends unknown[] = any[],
>(
  values: Iterable<Return | Error>,
): (this: Self, ...args: Args) => Return {
  const gen = (function* returnsValue() {
    yield* values;
  })();
  let calls = 0;
  return function () {
    const next = gen.next();
    if (next.done) {
      throw new MockError(
        `Not expected to be called more than ${calls} time(s)`,
      );
    }
    calls++;
    const { value } = next;
    if (value instanceof Error) throw value;
    return value;
  };
}

/**
 * Creates a function that resolves the awaited iterable values. Any awaited iterable values that are errors will be thrown.