+emi

Equivalence-based Mutation of CPS (e.g. Simulink) models

Running

• Set environment variable COVEXPEXPLORE to point to your seed model location
• Preprocess seeds by running experiment# 1, 2 and 3 using covexp.covcollect
• After preprocessing invoke emi.go() to generate mutants
• Use emi.report to see reports

Configuration

Configure cfg.m in MATLAB using edit emi.cfg

Mutation Strategies

Fixating output type of every block

Two issues: one generalising from the issue solved by emi.decs.FixateDTCOutputDataType -- since block output types may get changed in the mutants and would result in comparison errors. Other is a possible bug

TypeAnnotateByOutDTypeStr fixates output type of every block. TypeAnnotateEveryBlock fixates input types of every block.

See emi.decs.TypeAnnotateByOutDTypeStr

MUTATOR_DECORATORS = {
    @emi.decs.TypeAnnotateEveryBlock                % Pre-process
    @emi.decs.TypeAnnotateByOutDTypeStr              % Pre-process
    @emi.decs.DeleteDeadAddSaturation
    };

Fixating output type of DTC blocks

Issue: Data-type converters in the original model was getting a new output data type in the mutants, since their successors got change and Simulink was inferring new output data types for the DTC blocks. See emi.decs.FixateDTCOutputDataType

MUTATOR_DECORATORS = {
    @emi.decs.FixateDTCOutputDataType               % Pre-process
    @emi.decs.TypeAnnotateEveryBlock                % Pre-process
    @emi.decs.DeleteDeadAddSaturation
    };

Delete dead block and directly connect predecessors and successors

Issue: May change semantics in live (zombie) path

Code:

MUTATOR_DECORATORS = {
    @emi.decs.TypeAnnotateEveryBlock
    @emi.decs.DeleteDeadDirectReconnect
    };