added test for reading from file
added test for reading from file

khalibartan/pgmpy,vivek425ster/pgmpy,liquidmetal/pgmpy,abinashpanda/pgmpy,jhonatanoliveira/pgmpy,ankurankan/pgmpy,sandeepkrjha/pgmpy,ankurankan/pgmpy,liquidmetal/pgmpy,vivek425ster/pgmpy,jhonatanoliveira/pgmpy,kislayabhi/pgmpy,pratyakshs/pgmpy,palashahuja/pgmpy,pratyakshs/pgmpy,pgmpy/pgmpy,kris-singh/pgmpy,palashahuja/pgmpy,anaviltripathi/pgmpy,kislayabhi/pgmpy,sandeepkrjha/pgmpy,abinashpanda/pgmpy,yashu-seth/pgmpy,kris-singh/pgmpy,yashu-seth/pgmpy,khalibartan/pgmpy,anaviltripathi/pgmpy,pgmpy/pgmpy