have.subset()

[stevenvachon]

expect({...}).to.have.subset({...});
expect({...}).to.not.have.subset({...});

looks much nicer than containSubset().

[eagleeye]

From Wiki https://en.wikipedia.org/wiki/Subset

The relationship of one set being a subset of another is called inclusion or sometimes containment.

so "containment" is an official naming of relation between sets

[stevenvachon]

Ok, how about:

expect({...}).to.contain({...});
expect({...}).to.not.contain({...});

camelcase (containsSubset) simply doesn't look sentence-like.

[eagleeye]

@stevenvachon it's already used by other assertion http://chaijs.com/api/bdd/#method_include include(value)

@param { Object | String | Number } obj @param { String } message optional The include and contain assertions can be used as either property based language chains or as methods to assert the inclusion of an object in an array or a substring in a string. When used as language chains, they toggle the contains flag for the keys assertion.

expect([1,2,3]).to.include(2);
expect('foobar').to.contain('foo');
expect({ foo: 'bar', hello: 'universe' }).to.include.keys('foo');

[stevenvachon]

Since functions are objects in javascript, can we extend chai's builtin contain to have a property of subset with a value of a function?