tried to edit tests

__tests__/index.tests.js

@@ -1,19 +1,37 @@
-import fs from 'fs';
-import { fileURLToPath } from 'url';
 import path, { dirname } from 'path';
-import gendiff from '../index.js';
+import { fileURLToPath } from 'url';
+import fs from 'node:fs';
+import genDiff from '../index.js';
 
 const __filename = fileURLToPath(import.meta.url);
 const __dirname = dirname(__filename);
 
 const getFixturePath = (filename) => path.join(__dirname, '..', '__fixtures__', filename);
 const readFile = (filename) => fs.readFileSync(getFixturePath(filename), 'utf-8');
 
-test.each(['json', 'yml', 'yaml'])('gendiff_test_format', (format) => {
-  const filepath1 = getFixturePath(`file1.${format}`);
-  const filepath2 = getFixturePath(`file2.${format}`);
-  expect(gendiff(filepath1, filepath2)).toEqual(readFile('expectedStylish.txt'));
-  expect(gendiff(filepath1, filepath2, 'stylish')).toEqual(readFile('expectedStylish.txt'));
-  expect(gendiff(filepath1, filepath2, 'plain')).toEqual(readFile('expectedPlain.txt'));
-  expect(gendiff(filepath1, filepath2, 'json')).toEqual(readFile('expectedJson.json'));
+let pathToFile1;
+let pathToFile2;
+let pathToFile3;
+let pathToFile4;
+let resultPlainFormat;
+let resultStylishFormat;
+beforeAll(() => {
+  pathToFile1 = getFixturePath('file1.json');
+  pathToFile2 = getFixturePath('file2.json');
+  pathToFile3 = getFixturePath('file1.yml');
+  pathToFile4 = getFixturePath('file2.yml');
+  resultPlainFormat = readFile('expectedPlain.txt');
+  resultStylishFormat = readFile('expectedStylish.txt');
+});
+
+test('test genDiff to work with stylish format', () => {
+  expect(genDiff(pathToFile1, pathToFile2)).toBe(resultStylishFormat);
+
+  expect(genDiff(pathToFile3, pathToFile4)).toBe(resultStylishFormat);
+});
+
+test('test genDiff to work with plain format', () => {
+  expect(genDiff(pathToFile1, pathToFile2, 'plain')).toBe(resultPlainFormat);
+
+  expect(genDiff(pathToFile3, pathToFile4, 'plain')).toBe(resultPlainFormat);
 });