Using in-line syntax results in error: context.expect is not a function

[AJMiller]

Trying to use the new inline syntax like this:

describe('myFunction', () => {
  def('param', true);

  subject('fireFunction', () => myFunction($param));

  context('when the param is false', () => {
    def('param', false);

    it(() => is.expected.to.eql(false));
  });
});

results in the following error when running the test:

TypeError: context.expect is not a function
      at Object.get expected [as expected] (node_modules/bdd-lazy-var/global.js:420:24)
      at Context.<anonymous> (output/webpack:/myFunction.test.js:198:19)

Running the test using the older syntax works fine:

it('returns false', () => {
  expect($fireFunction).to.eql(false);
});

Using mocha + bdd-lazy-var. Any thoughts?

[stalniy]

Hm... Strange. I'll check it

[stalniy]

I put this:

describe('myFunction', () => {
  def('param', true);

  subject('fireFunction', () => $param);

  context('when the param is false', () => {
    def('param', false);

    it(() => is.expected.to.eql(false));
  });
});

in my tests and it works.

Could you please clarify what version of mocha, chai and bdd-lazy-var you use?

Do you have global.expect = chai.expect somewhere in configuration?

[stalniy]

This shorthand functions expect that expect function is available in global namespace

[AJMiller]

Thanks for the quick reply @stalniy. I'll take a look into it and report back. I didn't see that line in our codebase on a quick search, and I didn't see it mentioned in the installation steps for bdd-lazy-var.

Versions: Mocha: 5.2.0 Chai: 4.1.2 Bdd-lazy-var: 2.4.0

One difference I did notice is that your subject returns the value directly, where my example has the subject executing a function. Would that make a difference?

[stalniy]

Having expect On global level is a common practice. Jest & jasmine sets own expect implementation into global scope. The only exception is chai but usually people export chai.expect to global scope as well and use it everywhere in tests

[stalniy]

Update bdd-lazy-var to the latest version it’s 2.4.4

[AJMiller]

thanks @stalniy. Adding the following to our test startup script solved the issue:

import { expect } from 'chai';
global.expect = expect;