update mock

tests/renderStream.spec.ts

@@ -1,12 +1,19 @@
 import type {EChartsOption} from 'echarts';
-import fs from 'node:fs';
+import fs, {readFile} from 'node:fs';
 
 import {ConfigService} from 'app/config';
 import {renderStream} from 'app/renderStream';
 import {RenderData} from 'app/types';
 
 jest.mock('node:fs');
 
+jest.mock('node:fs', () => {
+ return {
+ ...jest.requireActual('node:fs'),
+ readFile: jest.fn(),
+ };
+});
+
 describe('renderStream', () => {
  it('can render graphs given a valid config and render data', async () => {
  const config = new ConfigService('./example');