Using file-test to test your generated file

#javascript #testing #test #jest

When we write a program that will generate some files, how do we test this kind of program? I always use the fs module, test if the directories or files are existed. But I need to write many boring codes for this.

So I write file-test, for the test cases that care about the generated.

Suppose I wrote a program that should generate this directory structure:

- root
  - readme.md
  - A
    - a.js
    - b.js
  - B
    - a.ts 
    - b.ts

With file-test, I can simply test it like:

const FileTest = require('file-test')

const ft = new FileTest(path.resolve(__dirname, './root'))

ft.includeFile('readme.md') // => true
ft.includeFile('blabla.md') // => false
ft.includeFile('A/a.js') // => true
ft.includeFile('A/b.js') // => true

ft.readFile('A/a.js') // => console.log('hello js')

ft.includeDirectory('A') // => true
ft.includeDirectory('B') // => true
ft.includeDirectory('A/a.js') // => false

ft.include([
  'readme.md',
  'A/a.js',
  'B/a.ts',
]) // => true

ft.include([
  'readme.md',
  'A/a.ts',
  'B/a.ts',
]) // => false

It is easy to use with Jest too:

test('directory structure', () => {
  expect(ft.includeDirectory('B')).toBe(true)
  expect(ft.includeDirectory('A/a.js')).toBe(false)
  expect(ft.readFile('A/a.js')).toEqual(`console.log('hello js')`)
  expect(ft.include([
    'readme.md',
    'A/a.js',
    'B/a.ts',
  ])).toBe(true)
})