Skip to content

Instantly share code, notes, and snippets.

@gaspaonrocks
Last active July 21, 2018 11:38
Show Gist options
  • Save gaspaonrocks/2f9ec9ac458bbbc4dc4c037284e5de7f to your computer and use it in GitHub Desktop.
Save gaspaonrocks/2f9ec9ac458bbbc4dc4c037284e5de7f to your computer and use it in GitHub Desktop.
using mock-fs with jest to assert the result of file system operations in a sync manner
import mock from 'mock-fs';
import fs from 'fs';
import fileHandler from '../utils/fileHandler';
beforeEach(() => {
// Creates an in-memory file system
mock({
'/test': {
'note.md': 'hello world!'
}
});
});
it('throws error if path doesn\'t exist', () => {
mock.restore(); // => called here to check if Error is thrown
const error = () => fileHandler.saveFileSync('/test/note2.md', 'ciao world!');
expect(error).toThrow();
});
it('saves a file given it\'s contents', () => {
fileHandler.saveFileSync('/test/note2.md', 'ciao world!';
expect(fs.existsSync('/test/note.md')).toBeTruthy();
mock.restore(); // => called here as in a regular afterEach
});
it('throws error if path doesn\'t exist', () => {
mock.restore(); // => called here to check if Error is thrown
const error = () => fileHandler.loadFileSync('/test/note.md');
expect(error).toThrow();
});
it('loads a file from disk', () => {
const actual = fileHandler.loadFileSync('/test/note.md');
expect(actual).toBe('hello world!');
mock.restore(); // => called here as in a regular afterEach
});
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment