Chai: expect(array).to.deep.include({...}) does not apply deep equality recursively

[bitliner]

As the title says,
if I run expect(array).to.deep.include(obj) I would expect to apply deep equality to each of the property of obj.

But it does not behave like this, is it a bug?

[keithamus]

@bitliner thanks for the issue.

Could you please give a more concrete example? What is array and obj in this context? Below seems work fine for me (Chai 2.1.1)

expect([ {foo: {bar:true} } ]).to.deep.include({ foo: {bar:true} });

[bitliner]

Sorry, my fault.
The variable arr instead of being an array it was an object, and the error message was

to have a property 'pubDate' of Sat, 26 Apr 2014 22:00:00 GMT, but got Sat, 26 Apr 2014 22:00:00 GMT

Using to.be.deep.eql it works fine.

[keithamus]

Hmm. Looks like you've probably got two different Date objects that you're testing against. Despite the Date's having the same _value_, they wont have the same _reference_, and so do not equal.

I guess .deep.include could offer the same semantics as .deep.equal but I'm not sure if it makes sense to have them both share the same behaviour... thoughts?

[blah238]

I am having a similar issue: https://github.com/chaijs/chai/issues/399

I have also tried using .deep.equal but the behavior _is_ the same for me.

[felixfbecker]

How do you do this with assert style? there is no assert.deepInclude()...

[bnord01]

This doesn't work for nested arrays either. I need to test whether an associative array contains some entry but the following fails:

[['a','A'],['b','B']].should.deep.contain(['a','A'])
--> 
AssertionError: expected [ [ 'a', 'A' ], [ 'b', 'B' ] ] to include [ 'a', 'A' ]

What I find surprising is, that it works as expected using include.deep.members:

[['a','A'],['b','B']].should.include.deep.members([['a','A']])

[lucasfcosta]

Hello guys, thanks for your reports! :smile:

@bnord01 Currently we don't even differentiate .deep.contain from .contain. The problem here is that, on assertions.js L214, we check the type of the passed value using _.type, which, under the hood, calls Object.prototype.toString.call(val) and returns array for arrays, instead of object, that's why it isn't getting deeply compared, only strictly compared (using ===).

This looks like a very easy fix. We could just change this line on assertions.js L214. If this condition was written as if (_.type(obj) === 'array' && typeof val === 'object') our problem would be solved, because when calling typeof for an Array, it returns object too, and therefore we will run a deep comparison. I just tried this here and all tests passed, including the same assertion @bnord01 posted.

Hi, @felixfbecker you could just use .assert.include, because, as I explained above, currently we don't differentiate .deep.include from .include.

What is your opinion about it, @keithamus, should we add support for a deep flag on the include assertion and compare using === when it's not present or should we just fix the issue @bnord01 reported for now? In my opinion it would be nice to have a strict (===) comparison, even if it's not so common, it may be worthwhile to cover it.

[felixfbecker]

@lucasfcosta imo the default should be to search by object reference. I would then expect assert.deepInclude or should.deep.include to do a deep comparison, just like equals and deepEquals behave.

[bnord01]

Currently we don't even differentiate .deep.contain from .contain.

@lucasfcosta that sounds not like desirable behavior to me. Indeed I was surprised that
[{}].should.not.contain({}) fails, while [{}].indexOf({}).should.equal(-1) succeeds.
If this is the intended behavior I think it should be documented with the includes method. Also in general it would be nice if a warning was issued if a non identity flag (like deep) is set on a method that doesn't support it. Looking at the documentation of deep it only says that it is used by equal and property but it is (at least) also used by members (which doesn't mention on what kind of target it can be used). Any reason not to support general ES6 iterables here?

[lucasfcosta]

@felixfbecker thanks for your feedback, I agree with you. Let's just wait for a third opinion on this just to make sure this should really be done. :smiley:

@bnord01 Thanks for sharing your thoughts. I'm not sure that warning would be a good idea, but we can talk about that and come to an agreement. When it comes to the deep flag I totally agree with you both about the .deep flag documentation and its behavior when used alongside include.
I'm not sure about it, but I think we just don't support ES6 iterables because this was implemented before the ES6 implementation or because no one else noticed and told us:laughing:
I hope you wouldn't mind if we wait for other maintainer's opinion, I'm pretty new here and I don't want to rush things or take decisions alone.
Thanks again for your feedback!

[meeber]

@lucasfcosta I just ran into this issue as well. It was my hope that deep.include would perform deep equality. I can work around it but it won't be as succinct ;(

[perrin4869]

Just ran into this issue when testing errors.

expect(validationError).to.deep.contain({
  name: 'ValidationError',
  errors: {
    subject: { kind: 'required' },
    content: { kind: 'required' },
  },
});

Basically, I want to test that a subset of the properties match deeply, since I cannot test all the properties, therefore I can't use deep.equal.

[dmansfield]

Another basic failure case for "include" is:

expect({k1: []}).to.include({k1: []});
-->
AssertionError: expected { k1: [] } to have a property 'k1' of [], but got []

Ultimately, it's using an '===' on the value assertion.

I've tried various "deep" flags and other tricks ("contain", "keys", "members") but to no avail. How can I make such a simple assertion (without using "property" as I don't want the assertion subject to change - which is why I'm using "include" in the first place).

[meeber]

Whoops forgot to close this issue. Fixed via #761, will be released in 4.x (alpha release will be available on npm soon).

[leo-thumbtack]

So what would be the proper syntax to solve this use case ?

[meeber]

@leo-thumbtack In Chai v4 (currently available via npm install chai@canary), the syntax is expect(myArray).to.deep.include(myObj).

[felixfbecker]

What about assert style?

[shvaikalesh]

@felixfbecker assert.deepInclude or assert.notDeepInclude

[leo-thumbtack]

Thanks

[deksden]

This fails with assert on chai v4.1.0:
expect([ { id: 1, name: 'first'}, { id: 2, name: 'second'}]).to.deep.include({ name: 'first' })

AssertionError: expected [ Array(2) ] to deep include { name: 'first' }

This is bug? How i can test if array include object with some specified properties?

upd: can be fixed with chai-subset plugin. Code is something like:

expect([ { id: 1, name: 'first'}, { id: 2, name: 'second'}]).to.containSubset([{ name: 'first' }])

[iraklisg]

@deksden chai-subsetplugin is what I was looking for :+1:

[djom202]

Hi,

I'd like to ask about if with function could be test this condition:

expect([ 'Hender' ]).to.deep.include('end')

Thanks.

[lucasfcosta]

Hi @djom20, I think you could try to use a matcher or search for a plugin which would allow you to do that easily in a single assertion.

As a last resort you could also do:

const checkItemsInclude = (arr, str) => arr.some(i => i.includes(str));
expect(checkItemsInclude(yourArray, 'end')).to.be.equal(true);

If you're checking for multiple items in the same array you can make that function curried:

const arrayIncludeMatcher = arr => str => arr.some(i => i.includes(str));
const arrayIncludes = arrayIncludeMatcher(yourArray);
expect(arrayIncludes('something')).to.be.equal(true);
expect(arrayIncludes('something wrong')).to.be.equal(false);

[djom202]

Hi @djom20, I think you could try to use a matcher or search for a plugin which would allow you to do that easily in a single assertion.

As a last resort you could also do:

const checkItemsInclude = (arr, str) => arr.some(i => i.includes(str));
expect(checkItemsInclude(yourArray, 'end')).to.be.equal(true);

If you're checking for multiple items in the same array you can make that function curried:

const arrayIncludeMatcher = arr => str => arr.some(i => i.includes(str));
const arrayIncludes = arrayIncludeMatcher(yourArray);
expect(arrayIncludes('something')).to.be.equal(true);
expect(arrayIncludes('something wrong')).to.be.equal(false);

Thanks, it's working great now.