Here is the list of things that can be tested with Pylint :
doc strings
modules / classes / functions / methods / arguments / variables name
number of arguments, local variables, branchs, returns and statements in functions, methods
required module's attributes
dangerous default values as arguments
redefinition of function / method / class
uses of the global statement
unauthorized constructions
strict indentation
lines'length
external modules dependancies
relative / wildcard imports
cyclic imports
uses of depreceted modules
unused variables / imports
undefined variables
redefinition of variable from builtins or from an outer scope
use of variable before assigment
methods without self as first argument
overriden methods signature
access only to existant members via self
attributes not defined in the __init__ method
supported interfaces implementation
unreachable code
total number of lines
total number of code lines
total number of docstring lines
total number of comments lines
total number of empty lines