I found another good resource to to check how is safe or weak a password. In the example below, I tested an easy password : " password " and The Password Checker ( Strength Test - http://rumkin.com/tools/password/passchk.php ) gives an estimation about how strong is this password in terms of strenght, entropy and charset size.
< 28 bits = Very Weak; might keep out family members
28 - 35 bits = Weak; should keep out most people, often good for desktop login passwords
36 - 59 bits = Reasonable; fairly secure passwords for network and company passwords
60 - 127 bits = Strong; can be good for guarding financial information
128+ bits = Very Strong; often overkill
Link : Strength Test
About password testing , read also : Test your password : How Secure Is My Password , Test your password : Microsoft password checker, Test your password : The Password Meter
Didn't knopw about this one, thanks.
I personally like this implementation: http://www.passwordmeter.com/ They show you how they evaluate the password with the different required options. Plus you can download the code.
Microsofts implementation always felt to me lacking in substance: https://www.microsoft.com/security/pc-security/password-checker.aspx?WT.mc_id=Site_Link
This one was top of the Google search & has a good write up: http://www.hammerofgod.com/passwordcheck.aspx