Resolve issue with to.be.json assertions Re #132

[dcoomber]

Proposed fix for #132 uses chai-http to enable the .to.be.json assertion.

[helloanoop]

@dcoomber The chai-http package seems to be checking at the response header property
https://github.com/chaijs/chai-http/blob/master/lib/http.js#L46

The expectation of the isJson is that we can assert any given path in the response is a json.
Ex: Given this response

{
   id: 1,
   name: "John",
   address: {
     "state": "NV"
   }
}

The user should be able to assert that the res.body.address is a json.

So, we need to extend chai so that it can check if a given var is json.
I use ChatGPT, I recommend you give it a try if you haven't used it.
I asked ChatGPT "write a chaijs plugin that checks whether a given variable is json or not ?"

And here is the answer

chai.use(function (chai, utils) {
  // Custom assertion for checking if a variable is JSON
  chai.Assertion.addMethod('json', function () {
    const obj = this._obj;
    const isJson = typeof obj === 'object' && obj !== null && !Array.isArray(obj) && obj.constructor === Object;

    this.assert(
      isJson,
      `expected ${utils.inspect(obj)} to be JSON`,
      `expected ${utils.inspect(obj)} not to be JSON`
    );
  });
});

You can add this at the top of the file here

I think this should solve our issue

[dcoomber]

@helloanoop Thank you for your patient explanation.

Although I have applied the suggested code, I am uncertain that this meets our needs.

In the example below, a string, number or boolean variable (e.g. Mickey, 50000 or true) is passing the isJson test where I think that they should be failing.

Given the following response payload:

{
  "firstname": "Mickey",
  "lastname": "Mouse",
  "totalprice": 50000,
  "depositpaid": true,
  "bookingdates": {
    "checkin": "2022-05-01",
    "checkout": "2022-05-31"
  }
}

When I assert that <<variable>> isJson

variable	then (expected result)	actual result	test outcome
res	fail	fail	✅
res.body	pass	pass	✅
res.body.firstname	fail	pass	❌
res.body.bookingdates	pass	pass	✅

I spent a few hours with ChatGPT working through different ways to code the Chai plugin but all my attempts were unsuccessful. This is the last iteration that I tried - it includes a JSON.parse step to confirm that the object is actually a JSON string.

chai.use(function (chai, utils) {
  // Custom assertion for checking if a variable is JSON
  function isJson(str) {
    try {
      JSON.parse(str.toString());
    } catch (e) {
      return false;
    }
    return true;
  }

  chai.Assertion.addMethod('json', function () {
    const obj = this._obj;
    const isJsonObj = isJson(obj) && typeof obj === 'object' && obj !== null && !Array.isArray(obj) && obj.constructor === Object;

    this.assert(
      isJsonObj,
      `expected ${utils.inspect(obj)} to be JSON`,
      `expected ${utils.inspect(obj)} not to be JSON`
    );
  });
});

I got VS Code setup so that I could debug while running, but was unable to get the breakpoints to work inside of the chai.use(function (chai, utils) {} block. To me it looks as if the custom plugin method json isn't being used.

[helloanoop]

@dcoomber This dep can be removed here.

[helloanoop]

To me it looks as if the custom plugin method json isn't being used.

@dcoomber To confirm this, you can put console.log() statements inside the chaijs json function. These logs will be displayed in the terminal where the electron app is running.

[dcoomber]

Thank you for the encouragement, @helloanoop

After reviewing https://www.chaijs.com/api/plugins/ along with stepping through some of the other assertions, I realised that we're looking to addProperty and not addMethod.

I've tested the updated assertion and its passing the positive and negative cases I've used (the failed assertions below are correctly failing).

[helloanoop]

Awesome @dcoomber !
I am sure you had had the high of "damn it, i finally cracked this" 😃

Can you remove the chai-http in package.json ?
Once done, this PR is good to merge.

[dcoomber]

@helloanoop I am thrilled that I was able to figure this out! Thank you for your help.

I've removed the chai-http package 😅 .

[helloanoop]

Nice work @dcoomber ! Merged !