Framework for calculation and presentation of likelihoods

My first addition to EzUnit is the implementation of a likelihood framework. Needed things are a view that displays the likelihood for a failure of a method, an extension point where different likelihood calculation methods can be added and some methods for calculating a likelihhod.

Likelihood calculation

I implemented four likelihood calculation methods. The first computes the quotient from the count of failures and the count of all calls of a method. The second calculates the test coverage of a method as the quotient from the count of all calls and the sum of all method calls. Then it calculates the failure likelihood and the passed likelihood as quotient from failures/passes and the count of all calls of a method. These three values are now taken to calculate the end likelihood in the following way. A difference is build from the failure and passed likelihood and this value is multiplied with the test coverage. This method should rate methods higher that are more tested. The third and the fourth are of the same type. They calculate a complexity of a method by there length in characters. In the one hand it is calculated the quotient from the length of method and the sum of the length of all methods and on the other hand it is calculated the quotient from a methods length and the length of the biggest method.

Displaying the result

The result is displayed as a tree. First comes the methods that have possible failures and under this methods there come the test name from where they called. Here it is defferenciated between failed and passed tests. Then it is displayed a overall likelihood and under this overall likelihood come all single likelihoods. The overall likelihood is calculated as the sum from all likelihoods. All single likelihoods go in this sum with the same weight.

Rate likelihood methods

To adjust the result you can vote or disable a likelihood method. A method should be voted if it helps to find the failure. The user has to decide when this is the case.


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