KobrA Flashcards
- Role of System Specification
o Describes externally visivle properties
o Defines supplied services and imported services
o The requirements the realizations have to fulfil
- Different Views
o Functional View – computations performed by component – Logic Based and Input Partitioning
o Behaviour View – states exhibited by the component and the events that change them – Graph Based
o Structural View – data manipulated by the component, its environment and any externally visible structure – Input Partitioning
- Reason for failure
o Specification itself be wrong
o Implementation may not correctly match the specification
- Software specifications need to be
o Readable
o Precise
o Easy to verify
- Two types of operations
o Changer operation – postcondition / change state of system – constructor or setter operation
o Inspector operations – never change the state – getter operations
Kobra concept
- strong concept of completeness
- strong concept of correctness
- Behavioural Model
■ describes how a system behaves in response to external stimuli
■ three important concepts are related in the behavioral model:
■ events : indivisible occurrences that have a location in space
and time
■ operations : encapsulated unit of functionality associated with
systems
■ states : A period of time in between events that determines how
the system will respond to the subsequent event
Mapping to a graph
■ state is mapped to a node, S i , called a state node
■ external transition is mapped to a node, T i , called a transition node, plus two edges from the initial state to T i and from T i to the
final state
■ each internal transition caused by a changer operations is mapped
to a node (a transition node (TN) ) plus two edges from the initial
state to TN and from TN to the final state
Mapping to logic coverage
■ inspectors are usually so simple, in general it is only necessary to
apply logic and input partitioning criteria to changer operations
