Testing

import { Test, TestingModule } from '@nestjs/testing';
import { EChartsService } from '@nestjsforge/echarts';
import { ChartsService } from './charts.service';

describe('ChartsService', () => {
  let service: ChartsService;
  let echarts: jest.Mocked<EChartsService>;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [
        ChartsService,
        {
          provide: EChartsService,
          useValue: {
            renderToBuffer: jest.fn().mockResolvedValue(Buffer.from('fake-png')),
            renderToBase64: jest.fn().mockResolvedValue('ZmFrZS1wbmc='),
          },
        },
      ],
    }).compile();

    service = module.get(ChartsService);
    echarts = module.get(EChartsService);
  });

  it('should render bar chart', async () => {
    const buffer = await service.renderBarChart();
    expect(echarts.renderToBuffer).toHaveBeenCalledTimes(1);
    expect(Buffer.isBuffer(buffer)).toBe(true);
  });
});

describe('EChartsService (integration)', () => {
  let service: EChartsService;

  beforeAll(async () => {
    const module = await Test.createTestingModule({
      imports: [EChartsModule.forRoot({ poolSize: 1, timeout: 30_000 })],
    }).compile();

    const app = module.createNestApplication();
    await app.init();
    service = module.get(EChartsService);
  });

  afterAll(async () => {
    await app.close();
  });

  it('should render a real chart', async () => {
    const buffer = await service.renderToBuffer({
      xAxis: { type: 'category', data: ['A', 'B', 'C'] },
      yAxis: { type: 'value' },
      series: [{ data: [1, 2, 3], type: 'bar' }],
    });
    expect(Buffer.isBuffer(buffer)).toBe(true);
    expect(buffer.length).toBeGreaterThan(1000);
  });
});