The
testing of the software systems or applications apart from the human labor is
aided by a variety of testing techniques. In this article we are going to
discuss about three of such software testing techniques mentioned below:
- State transition diagrams,
- Decision tables and
- Activity diagrams.
1. Test Design Technique - State transition diagrams
- These are some kind of diagrams that give a detailed description of the
behavior of the software systems and applications.
- The basic condition
for the state transition diagrams is that the description of the software system
or application should be composed of a particular number of states and employ
a reasonable abstraction.
- There are various forms of state diagrams and
all of them differ with each other in respect of their semantics.
- However, the description provided by the state diagrams is quite concise and represents only an abstract view.
- The behavior of the software system or
application is first analyzed and represented in series of events that
could take place in one or more possible states.
- Each diagram provides a
visual representation of the objects belonging to a particular class and the
different states of the objects spread through out the software system or
application can be tracked.
- Also, the finite state machines can be
represented graphically by the state transition diagrams. - The use of state
diagrams under the concept of finite machines was introduced by C.E.
Shannon and W. Weaver.
“Directed form” is the most classic form of the
state transition diagrams for a finite automation (FA) or finite state
machine. It consists of the following elements:
(i) Vertices: a finite set of
states which are represented by circles bearing a unique designator label.
(ii) Input symbols: a finite
collection of input designators.
(iii) Output symbols: a finite
collection of output designators.
(iv) Edges: meant to represent
the state transitions.
(v) Start state
(vi) Accepting state
2. Test Design Technique : Decision Tables
- This test design technique represents a compact way to
model complicated logic by associating the conditions with the actions
that have to be performed.
- The decision tables consists of 4 quadrants as
stated below:
(i) Conditions
(ii) Condition alternatives
(iii) Actions
(iv) Action entries
- Each
decision in a decision table corresponds to a variable, predicate and relation
whose possible values are stated in a list among the condition alternatives.
- Each
action is equivalent to procedures or operations that are to be performed.
- The
actions to be performed are specified by the entries made.
- The decision tables
are known to vary widely according to the way in which the conditions alter and
also according to the representation of the action entries.
- Most of the
decision tables make use of the simple true or false values that are used to
represent the alternatives to the conditions stated in it.
3. Test Design Technique : Activity Diagrams
- This is another graphical aid that represents the work
flows of step wise actions and activities along with aspects like choice,
concurrency and iteration.
- Usually these diagrams make use of the unified
modelling language to provide a description of the operational and business
step by step work flows of the components of a software system or
application.
It constitutes of some basic shapes like:
(i) Diamonds: represent
decisions.
(ii) Black circles: represent
the start of the activity.
(iii)Encircled black circles:
represent the end of the activity.
(iv)Rounded rectangles:
represent activities.
(v) Bars: represent start
(split) or end (join) of the activities that are concurrent.
