Should.js chaining multiple assertions on a single property

Question

I've got an object like this:

var obj = {
    "uuid": "60afc3fa-920d-11e5-bd17-b9db323e7d51",
    "type": "candy"
}

I want to write a test that checks first that the object has the property 'uuid' in the first place, and then that 'uuid' is a specific length (36 chars).

Trying this doesn't work

obj.should.have.property('uuid').which.should.have.length(36)

It fails with:

Uncaught AssertionError: expected Assertion {
  obj: '60afc3fa-920d-11e5-bd17-b9db323e7d51',
  params: { operator: 'to have property \'uuid\'' },
  negate: false } to have property 'length' of 36 (got [Function])

And this (which actually doesn't make syntactic sense anyway - since it would apply to the parent object not the value)

obj.should.have.property('uuid').and.be.length(36)

Which fails with:

Uncaught TypeError: usergridResponse.entity.should.have.property(...).which.should.be.equal.to is not a function

Even this doesn't work:

obj.should.have.property('uuid').which.equals('60afc3fa-920d-11e5-bd17-b9db323e7d51')

So what's the correct way to chain assertions on the property of an object?

artberri · Accepted Answer · 2015-11-23T19:51:02.927

3

I think that this could be the better option:

var session = {
    "uuid": "60afc3fa-920d-11e5-bd17-b9db323e7d51",
    "type": "candy"
};

session.should.have.property('uuid').with.a.lengthOf(36);

Or this if you want to choose should twice, but I don't think that this is a proper way (explained bellow).

var session = {
    "uuid": "60afc3fa-920d-11e5-bd17-b9db323e7d51",
    "type": "candy"
};

session.should.have.property('uuid').which.obj.should.have.length(36);

You can see them working here:

https://jsfiddle.net/Lz2zsoks/

.an, .of, .a, .and, .be, .have, .with, .is, .which are just chainers that don't do nothing.

Update

As a response to @denbardadym I'll try to explain why you should not use should twice:

You won't use it twice in natural language, so it's better to don't use it in tests
Should.js is not intended to be used in that way. You will not find any example of that usage in the library documentation.

edited Nov 23 '15 at 19:51

answered Nov 23 '15 at 19:16

artberri

1,327
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It is not right way to suggest use .should twice - better to explain why it is wrong. – den bardadym Nov 23 '15 at 19:19
Ok, already explained. But it is also not right way to write an answer without giving an answer ;) – artberri Nov 23 '15 at 19:30
Also the obj shouldn't be length 36, obj.uuid should be – brandonscript Nov 23 '15 at 19:38
@remus The first option I'm giving you works and I guess it has a proper syntactic. The second one is checking the length of the property not the object, I understand it fine. `.obj` is the way to access the property value, if you see my answer I changed the name of your ariable `obj` to `session`. – artberri Nov 23 '15 at 19:48
Definitely your first suggestion is what I was looking for. And I can also use that with `.equal('...')` (instead of `.with.a.lengthOf`) – brandonscript Nov 23 '15 at 19:51
1

For clarity, I ended up with: `obj.should.be.an.Object.and.have.property('uuid').with.a.lengthOf(36)` – brandonscript Nov 23 '15 at 20:05
1

To try to continue helping: obj.should.be.an.Object is not asserting nothing, you needto use the function (I think that the doc is wrong, if you don't do obj.should.be.an.Object() it will not work) Check this fiddle: https://jsfiddle.net/a1ds5q99/ – artberri Nov 23 '15 at 20:21
Also, I would remove totally the object assertion because in Javascript there are a lot of things that are instances of an Object (like arrays), so anything that can have a property will assert to true if you check if it's an Object. – artberri Nov 23 '15 at 20:23

score 1 · Answer 2 · answered Nov 23 '15 at 19:08

1

First statement failed because you call .should twice - second time you assert on assertion, it should be:

obj.should.have.property('uuid').which.have.length(36)

(error message literally sais, that Assertion {...} has no property length)

Second statement does not throw for me:

obj.should.have.property('uuid').and.be.length(36)

(your error message looks like not that assertion fail for you)

Last statement - there is not .equals assertion - it should be .equal. And it of cause throws for me because "0320a79a-920d-11e5-9b7a-057d4ca344ba" !== "60afc3fa-920d-11e5-bd17-b9db323e7d51"

Hope it helps.

answered Nov 23 '15 at 19:08

den bardadym

2,747
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Think I'm making progress. Uuid not matching was a copy fail on my part . `.length` is probably because it's `.lengthOf` instead of `.length`. Will fiddle some more. – brandonscript Nov 23 '15 at 19:12
That is ok =). I suggest you for such question use gitter chat for should.js repo, i usually answer faster. – den bardadym Nov 23 '15 at 19:14

Should.js chaining multiple assertions on a single property

2 Answers2