What is Test Design and Test modeling

 Test modelling - Activity of representing system/feature under test as a model. 

A sample hierarchy

System

        Entities/Objects/Users (Roles)

            Dependencies between objects

                Relationships - IS A and HAS A (Type and containment)

                    One to one, One to Many

                        Properties (variables and constants)

                                Values (domain) of properties

                                    Default values, boundaries of values

                                        Combinations of Values to create test scenarios

Object - Action - State Change.

List actions on each objects.

Create a map of what will happen when an action on object happens

Simultaneous actions

Dead locks

Hangs

how do we use  BB design techniques

EQ partitioning

State machine

Decision Tree

Combinatorics

Take  a par of variables and create a Grid.

GUI Testing check lists (applicable to new GUI)

Static vs Dynamic Models

Model - when nothing is happening. No user interaction

Dynamic - when users are interacting

Time element

It might help to user Object Oriented Design to represent above idea.

There are objects - have properties and functions.

Nouns and Verbs

System will have objects/entities. Objects have properties, properties can be constant or variable.

Take each variable - explore the domain of the variable. See what kind of values it can take and 

String these variable values into test scenarios.

This act of modeling - goes through iterations. It's like a photo film negative development. With each iteration  - various features of system start showing up.

Idea of Test coverage -

Imagine a 2 D shape - area of features in two dimensions.

Covering area means exercising the walking through the area.

how about Volume ? 3rd dimension - features and values