text: const assert = require('assert');
  const validateEssaySubmission = require('../lib/validateEssaySubmission');
  const fs = require('fs');
  
  describe('validateEssaySubmission.js', () => {
      const validFile = {
          name: 'sample.txt',
          mimetype: 'text/plain',
      }
      const invalidFile = {
          name: 'sa@#$#ple.txt',
          mimetype: 'tortoise'
      }
  
       it('return true when file exists.', () => {
           assert.equal(true, validateEssaySubmission(validFile));
       });
  
       it('return false when mimetype is unsupported.', function(){
           assert.equal(false, validateEssaySubmission(invalidFile));
       });
  
       it('return true when name is valid.', function(){
           assert.equal(true, validateEssaySubmission(validFile));
       });
  
       it('return false when name is invalid - contains invalid characters.', function(){
           assert.equal(false, validateEssaySubmission(invalidFile));
       });
  
   });
  