How to assert null with should

should.be.null throw an error saying should.be doesn’t have this null method.

How to transform the expect(null).to.be.null to should phrases?

[logicalparadox]

Well, you have a couple of options…

var chai = require('chai')
  , should = chai.should()
  , example = null;

I am assuming you are trying the following and its not working…

example.should.be.null;

The should interface extends Object.prototype with the should keyword and since null is not an Object… etc.

Here are a few of the alternatives, given that you have var should = chai.should(); as opposed to just calling chai.should().

// will test example to be equal to either `null` or `undefined`.
should.not.exist(example);

// if you need exactly null
should.equal(example, null);

In most cases the not.exist will likely work for you, especially if you are testing async callbacks in node.

db.get('abc', function (err, doc) {
  should.not.exist(err);
  should.exist(doc);
  // ...
});

Hope that helps!

[elliotf]

should.be.null(example)

looks nice, too.