Adds tests for SELECT modifier

[dmarcelino]

As mentioned in https://github.com/balderdashy/waterline/issues/366#issuecomment-102396946 this PR adds tests for the SELECT modifier.

Unfortunately, as happened previously on PR #53 sails-mongo is blocking this from being merged as it breaks the tests: https://travis-ci.org/balderdashy/waterline-adapter-tests/jobs/62718504#L545.

Remaining task:

• Fix sails-mongo balderdashy/sails-mongo#281

[dmarcelino]

As a side note, given balderdashy/waterline#997 we probably should add .find({ select: []}).populate() tests to the Associations interface to confirm associated records are not impacted by the select modifier.

[dmarcelino]

All tests passing, this one is ready merge!

@devinivy, mind giving this a look?

[devinivy]

Looks good! Brings up a question– if you findOne using select then save the record, are those undefined fields updated to be empty or ignored by waterline?

Also, does it make more sense to use assert.notProperty(x, y) or assert.isUndefined(x[y]) instead of assert.equal(x[y], undefined)? In any case, these tests look good to me.

[dmarcelino]

if you findOne using select then save the record, are those undefined fields updated to be empty or ignored by waterline?

I believe waterline ignores undefined fields but saves null fields.

Also, does it make more sense to use assert.notProperty(x, y) or assert.isUndefined(x[y]) instead of assert.equal(x[y], undefined)? In any case, these tests look good to me.

I'm not familiar with assert.notProperty() or assert.isUndefined(), nor I see them in Node.js docs... but you do have a point. Perhaps we should use assert('y' in x === false)?

[dmarcelino]

@devinivy, I've added the function assertNotProperty which asserts the property is not present in the retrieved record. It makes the tests more strict and also more coherent with the intended behaviour. Tests still pass for all official adapters which is reassuring 😀

[devinivy]

Awesome! I'd say merge away! I was getting confused with the Chai assertion library.

[dmarcelino]

Fair enough, merged, and thanks for the feedback! 😉