Piping message through should syntax, better Throws verbosity

[scottnonnenberg]

Found myself having difficulties with 'expected 5 to equal 3' or 'expected true to equal false' messages, I thought I'd make it easier to give myself debugging hints later.

Also, I want to know what happened when an unexpected exception is thrown, so I made it give me more detail.

Also of note:

• keys() does fancy stuff with its arguments, so I couldn't add a msg parameter. throws() similarly had a number of parameters, so you only get the message piped through if you give it both an exception and a message to look for within that exception.
• added some missing root should tests for equal and Throw
• added some tests to ensure that the inner length checks for above/below/within still pipe the message through

[travisbot]

This pull request passes (merged 941f992 into e8cc23d).

[travisbot]

This pull request passes (merged 57a6e04 into e8cc23d).

[domenic]

Can you give some examples of what this would look like? (E.g. so we could include them in the docs.) Also, any reason not to add it to expect?

I just got approached at NodeConf summer camp about what I think is the same feature. He said "it's the one thing missing from Chai" that he got in should.js. So, +1

[logicalparadox]

Style changes:

• Since on one line, the { and } are unnecessary.
• You can shorten the if statement to if (msg)...

[logicalparadox]

The other issue I see is that if your using the expect interface you can do the following...

expect(14, 'msg').to.be.a('number', 'anthrmsg');

...in which case the original msg would be overwritten. Something to note for the docs.

[scottnonnenberg]

It actually works for Expect, based on where I made the changes. Just added a commit including this new behavior in the Expect tests.

Example:

expect(temp).to.be.within(70, 80, 'comfortable temperature');
temp.should.be.within(70, 80, 'comfortable temperature');

On failure, the error message would be:

"comfortable temperature: expected 60 to be within 70..80"

[logicalparadox]

Thanks. I also added a bit of documentation to the inline comments.