SBFL_improvemment

[mguerrinha]

Context

Implementation of a formula that improves the final ranking

Check lists

• Unit tests
• Test pass
• Coding style (indentation, etc)

Additional comments

According to the paper "Enhancing Spectrum Based Fault Localization Via Emphasizing
Its Formulas With Importance Weight" it is possible to improve the ranking of the tested methods by multiplying the result given by the SBFL formulas by the formula ef/(ef + nf). This will emphasize methods that are executed by more failing
tests and lower the rank of methods that are executed by less failing tests.

• ef: represents the number of failed test cases covering the
  program element 𝑒.
• np: represents the number of passed test cases not covering
  the program element 𝑒.
• nf: represents the number of failed test cases not covering
  the program element 𝑒.

[jose]

Thanks @mguerrinha for contributing to GZoltar. Could you please provide more context/info of these changes?

[jose]

Thanks @mguerrinha for the additional comments. Any chance you could add a new option/parameter to enable such multiplication? I would say that by default, GZoltar should not compute such multiplication; only when enabled.

You can see the current set of GZoltar's options/parameters in here (for the CLI module) and here (for the Maven module).

[mguerrinha]

Thanks @jose for the reviews. In the last commit the multiplication is called only when it's enabled. However I'm not sure if the organization and changes I had to make are the most correct.