const CHUNK_SIZE = 1000;

const generateNodeIds = (count) => {
  Boolean(count);
  return [];
};

const generateDbResponse = (nodeIds) => {
  Boolean(nodeIds);
  return [];
};

const makeShouldReturn = (nodesCount) => {
  const title = nodesCount === 0 ? 'an empty array' : 'these node IDs';

  const nodeIds = generateNodeIds(nodesCount);
  const dbResponse = generateDbResponse(nodeIds);

  beforeEach(() => {
    spyOnSelect.mockResolvedValue(dbResponse);
  });

  afterEach(() => {
    spyOnSelect.mockReset();
  });

  it(`it should return ${title}`, async () => {
    const actualIds = await invoke();
    expect(actualIds).toEqual(expectedIds);
  });
};

describe('getNodeIds()', () => {
  describe(`when the database`, () => {
    describe(`contains no nodes`, () => {
      const nodeIds = generateNodeIds(0);
      makeShouldReturn(nodeIds);
    });

    describe(`contains less than one chunk size nodes`, () => {
      const nodeIds = generateNodeIds(Math.round(CHUNK_SIZE * 0.5));
      makeShouldReturn(nodeIds);
    });

    describe(`contains more than one chunk size nodes`, () => {
      const nodeIds = generateNodeIds(CHUNK_SIZE * 2);
      makeShouldReturn(nodeIds);
    });
  });
});