对带有Tape和Sinon的ForEach进行JavaScript功能的单元测试

Question

I am struggling to unit test the following function. In particular I cannot get it to cover the highlighted code:

function authCert(trustedCAFile){
    let ca = [];
    let cert = [];
    let trustedCA = String(fs.readFileSync(trustedCAFile));
    let trustedCALines = trustedCA.split("\n");

    trustedCALines.forEach(function(entry){

    cert.push(entry);
    if(entry.match(/-END CERTIFICATE-/)){
        **ca.push(cert.join("\n"));
        cert = [];**
    }
});

return ca;
}

This is my current test:

let test = require('tape');
let rewire = require('rewire');
let sinon = require('sinon');
let fs = require('fs');
let proxyquire = require('proxyquire');

test('should cycle through trusted ', function(t) {
  let authCert = rewire('../authCert');
  let getAuthCerts = certUtils.getAuthCert;

  let certStub = 'test';

  let fsStub = {
      readFileSync: () => {}
  };

  let ca = [];
  ca.push('1');

  certUtils.__set__('fs', fsStub);

  let result = getAuthorisedCerts(certStub);

  t.deepEquals(result, []);
  t.end();

});

I have looked at the documentation but as a noob I am unsure how to go about getting coverage and testing the highlighted code.

If anyone could help me or point me in the right direction I'd be very grateful.

Thanks

Answer 1

You don't need proxyquire (not actually being used) or rewire to do the testing you want to do.

We can just use sinon to stub the fs object for the tests.

In terms of getting the coverage you wanted, all you needed to do was to make the readFileSync stub actually return something containing at least one '-END CERTIFICATE-' .

const test = require('tape');
const sinon = require('sinon');
const fs = require('fs');

const certUtils = require('../authCert');
const caFilePath = 'test';

test('should return each certificate', function(t) {
  const fileContents = 'cert1\n-END CERTIFICATE-\ncert2\n-END CERTIFICATE-';
  const fsStub = sinon.stub(fs, 'readFileSync').returns(fileContents);
  const result = certUtils.getAuthCert(caFilePath);

  fsStub.restore();

  t.deepEquals(result, ['cert1\n-END CERTIFICATE-', 'cert2\n-END CERTIFICATE-']);
  t.end();
});

---

I've taken some liberties in terms of let/const and structuring the file, the key changes you need are making the stub return the string I've called fileContents .