Raises errors when giving encryption as non-Hash object

[satoryu]

In #250 , Net::LDAP of the latest version 0.13.0 accepts encryption options on its initializer. It causes an error when creating a connection as reported.

This PR provides a validation which check whether a given encryption option is a Hash or not.

[tonobo]

👍 it would be nice to validate all given parameters from constructor.

[jch]

Can we switch this to @encryption && !@encryption.is_a?(Hash)? This makes the nil check implicit, and the && operator is higher precedence than and (doesn't matter in this case, but I prefer it when used in a conditional)

[mynameisrufus]

These operators still hurt my brain, if we replace the and operators in the this codebase to && all the tests fail.

http://devblog.avdi.org/2014/08/26/how-to-use-rubys-english-andor-operators-without-going-nuts/

[jch]

Alternatively, we could also use a single type check with @encryption.respond_to?(:[]). I don't have a strong preference here.

@mynameisrufus why would && fail here?

[mynameisrufus]

Not here specifically, but when trying to replace and with && throughout the entire codebase (I tried it) all the test fail :)

[jch]

Thanks for clarifying. I wasn't trying to make so bold a claim ;)

[satoryu]

@jch @mynameisrufus Thank you for pointing out this condition. made my understanding about these operators clear 👍