  Testability is the probability whether tests will detect a fault, given that
a fault in the program exists. How efficiently the faults will be uncovered
depends upon the testability of the software. Various researchers have proposed
qualitative and quantitative techniques to improve and measure the testability
of software. In literature, a plethora of reliability growth models have been
used to assess and measure the quantitative quality assessment of software
during testing and operational phase. The knowledge about failure distribution
and their complexity can improve the testability of software. Testing effort
allocation can be made easy by knowing the failure distribution and complexity
of faults, and this will ease the process of revealing faults from the
software. As a result, the testability of the software will be improved. The
parameters of the model along with the proportion of faults of different
complexity to be removed from the software have been presented in the paper .We
have used failure data of two object oriented software developed under open
source environment namely MySQL for python and Squirrel SQL Client for
estimation purpose
