Write unit tests for all examples on site/docs

[deni-zen]

For every code snippet/example in the documentation, you need to write a unit test to make sure that example works as expected. This will ensure that the documentation always has working code samples. There's nothing worse than copying and pasting a code sample directly from a library's homepage and having it not work. Makes the library look very not good!

[nozavroni]

I'll do this on the next release