Theory and Practice of Co-verification Process: UniTesK Story

1
Theory and Practice ofCo-verification Process
UniTesK Story

• RedVerst group of ISP RAS
• Alexander K. Petrenko
• Victor V. Kuliamin
• http//www.ispras.ru

2
Overview

• Introduction Why co-verification?
• Main part What is UniTesK?Solving Engineering
  Problems
• Case studies

3
What these numbers mean?
9 1
180 ?109 21 ?109
total revenue of US software development companies loss caused by inadequate testing infrastructure for US economy1

• The Economic Impacts of Inadequate Infrastructure
  for Software Testing,
• NIST Report, May 2002

4
Waterflow Process Model
Requirements
Design
Implementation
Testing
Deployment
5
Iterative Process Model
Requirements
Design
Implementation
Testing
Deployment
6
Agile Development Methods Expansion
Percent of organizations using modern development
methods
According to The Decision is in Agile versus
Heavy Methodologies by Robert Charette, Cutter
IT Journal, vol. 2, No. 19, 2002 http//www.cutter
.com/freestuff/apmupdate.html
7
Agile Development Methods Expansion
Percent of organizations recognizing more than
50 of projects as agile
According to The Decision is in Agile versus
Heavy Methodologies by Robert Charette, Cutter
IT Journal, vol. 2, No. 19, 2002 http//www.cutter
.com/freestuff/apmupdate.html
8
Inadequate Quality of Software
Loss Potential Cost Reduction Total Sales
Software Vendors 21.2?109 10.6?109 180?109
Software Users 38.3?109 11.7?109
Total 59.5?109 22.2?109
The Economic Impacts of Inadequate Infrastructure
for Software Testing, NIST Report, May 2002
9
Evolution of Testing

• Localization of errors
• Demonstration of errors
• Testing is the process of executing a program or
  system with the intent of finding errors Myers,
  1979
• The purpose of testing is to show that a program
  has bugs Hetzel, 1988
• Evaluation of quality
• Testing is the process of operating a system or
  component under specified conditions, observing
  or recording the results, and making an
  evaluation of some aspect of the system or
  component IEEE 90

10
Co-verification

• Verification confirms that activity products
  properly reflect the requirements specified for
  them at the beginning of the activity.
• Co-verification process
• Perform verification of activity before
  proceeding to the dependent activities
• Prepare all the artifacts needed for verification
  concurrently with main activity products

11
Co-verification Development Process
Business Modeling
Deployment
Requirements
Integration
Architecture Design
Implementation
Component Design
12
Main Part Overview

• Traditional approaches to verification
• UniTesK approach
• Example

13
Traditional Software Development Process
Design and development Verification

• Requirements Analysis
• Design
• Implementation-debugging

• Requirements Elicitation
• Test Case Design
• Test Implementation
• Test Execution
• Test Result Analysis

14
Co-verification Process
Design and development Verification

• Requirements Analysis
• Design
• Implementation-debugging

• Requirements Elicitation
• Test Case Design
• Test Implementation
• Test Execution
• Test Result Analysis

15
UniTesK Approach
UniTesK
Tools
.N_at_T
J_at_T
CTesK
VDMTesK
Uniform Test Architecture
Uniform Specification Extension
Integration with Development Environments
Foundations
Model Based Testing
16
Requirements Formalization
Requirements
Requirements
Formal Specifications
17
Co-verification Support
Formal Specifications
Requirements
Ambiguity? Incompleteness?
Inconsistency?
18
Engineering Problems (1)

• Specification technique should support
• Easy transformation of requirements into
  specifications
• Easy automation of further test development
• Functional test coverage definition
• High reusability of specifications
• Specification notation should not require special
  education and skills

19
Specification Techniques

• ExecutableImperative state based specifications
• ConstraintsState based data type constraints,
  pre- and postconditions, internal invariants
• AxiomaticAction based axioms

20
Executable Specifications

• Are very close to some implementation
• Are easy to use in the industry
• Can be transformed into prototypes
• Are not close to requirements( v e½ln
  lim(xn1 ½(xn x/xn)) )
• Unsuitable for test coverage measurement
• Can cause problems with conformance checkingHow
  to compare the results?
• Are highly reusable as executable code
• But are low reusable as criteria of correctness

21
Constraint Specifications

• Have the structure similar with implementation
• Are easy to use in the industry
• But have different form
• Are close to requirements in most cases
• Are easy to construct from requirements
• Suitable for test coverage measurement
• Counterexample memory management subsystem
• Can be directly used in conformance checking
• Special constructs enabling reuse can be added

22
Axiomatic Specifications

• Are far from common implementations and have
  greatly different structure
• Can hardly be introduced in the industry
• Are usually far from requirements
• Are hard to develop in real-life projects
• Can hardly be used for coverage measurement
• But sometimes are the only appropriate form
• Can be used for conformance checking
• But provide poor error localization
• Reusability is a problem

23
Comparison of Specification Techniques
24
Specification Notation

• Specification language
• Suitable for capture abstract properties
• Has formal semantics
• Requires complex mediator layer for
  implementation
• Requires special education, mastering is enduring
• Extension of programming language
• Abstract concepts can be added by libraries
• Ambiguous parts of language can be excluded
• Complex mediators are not required
• Mastering can be made more effective
• Facilitates co-verification process

25
UniTesK Specification Technique

• Constraint Specifications
• Preconditions and postconditions of operations
• Data type constraints
• Functional coverage description based on
  specification structure

UniTesK
.N_at_T
J_at_T
CTesK
VDMTesK
Uniform Test Architecture
Uniform Specification Extension
Integration with Development Environments
Model Based Testing
26
UniTesK Specification Technique

• Constraint Specifications
• Preconditions and postconditions of operations
• Data type constraints

specification Operation() pre block, returning
Boolean value post block, returning Boolean
value use _at_ to refer to pre-value of expressions
invariant Invariant() block, returning Boolean
value
27
Priority Queue Example
0
5
2
enq ()
enq ()
deq ()
enq ()
5
5
4
3
1
1
size ()

• void enq (Object obj, int priority)priority ?
  Min_Priority, Max_Priority
• Object deq ()
• int size ()

28
J_at_va Specification Extension of Java

• specification package pqueue
• public class PQueueSpecification
• specification public void enq(Object obj, int
  prty)
• reads obj, prty
• updates items.?, priorities.?
• pre return obj ! null
• post
• int i 0
• for(i 0
• i lt items.size()
• ((Integer)priorities.elementAt(i)).i
  ntValue() gt prty
• i
• )
• ...

UniTesK
.N_at_T
J_at_T
CTesK
VDMTesK
Uniform Test Architecture
Uniform Specification Extension
Integration with Development Environments
Model Based Testing
29
Model State Definition

• specification package
• public class PQueueSpecification
• // List of elements of the queue
• public List items new List()
• // Accompanying list of their priorities
• public IntList priorities new IntList()

30
Data Integrity Constraints Lists are not Null

• public class PQueueSpecification
• public List items new List()
• public IntList priorities new IntList()
• invariant ListsAreNotNull()
• return items ! null priorities ! null

31
Data Integrity Constraints Lists Sizes are
Equal

• public class PQueueSpecification
• invariant ListsSizesAreEqual()
• return items.size() priorities.size()

32
Data Integrity Constraints Priorities Lie in
the Range

• public class PQueueSpecification
• public static int Min_Priority
• public static int Max_Priority
• invariant PrioritiesLieInTheRange()
• for(int i 0 i lt priorities.size() i)
• if( priorities.get(i) lt Min_Priority
• priorities.get(i) gt Max_Priority
• )
• return false
• return true

33
Data Integrity Constraints Priorities do not
Increase

• public class PQueueSpecification
• invariant PrioritiesDoNotIncrease()
• for(int i 1 i lt priorities.size() i)
• if( priorities.get(i-1) lt priorities.get(i)
  )
• return false
• return true

34
Operation Specification size() Method

• public class PQueueSpecification
• specification public int size ()
• reads this.?
• pre return true
• post
• return size items.size()

35
Operation Specification enq() Method

• public class PQueueSpecification
• specification public void enq (Object obj, int
  prty)
• reads obj, prty
• updates this.?
• pre
• return obj ! null
• Min_Priority lt prty
• prty lt Max_Priority
• post
• int i 0
• for(i 0
• i lt items.size() priorities.get(i)
  gt prty
• i
• )
• PQueueSpecification new_state
  (PQueueSpecification)_at_clone()

36
Auxiliary Methods

• public class PQueueSpecification
• public boolean equals (PQueueSpecification
  other)
• return items.equals(other.items)
• priorities.equals(other.priorities)
  
• public Object clone ()
• PQueueSpecification result new
  PQueueSpecification()
• result.items (List)items.clone()
• result.priorities (IntList)priorities.clone(
  )
• return result

37
Operation Specification deq() Method

• public class PQueueSpecification
• specification public Object deq ()
• updates this.?
• post
• if(items.isEmpty())
• return deq null items.isEmpty()
• else
• PQueueSpecification new_state
  (PQueueSpecification)_at_clone()
• Object result new_state.items.first()
• new_state.items.removeFirst()
• new_state.priorities.removeFirst()
• return this.equals(new_state) deq
  result

38
Coverage Goals Definition
Formal Specifications pre
--------------------------- post
---------------------------
--------------------------------------------------
--------------------------------------
-------- ------------ ----------------------
--------------- ----------------------
------------------------
---------------------------------------------
------------------------------------------------
-- ---- --------------------------
-----------
Requirements
Testable Specifications pre
--------------------------- post
---------------------------
--------------------------------------------------
--------------------------------------
-------- ------------ ----------------------
--------------- -----------------------
-----------------------
----------------------------------------------
-----------------------------------------------
--- ---- ------------------------------
-------
Test Case 1 --------------- --------------- ------
--
1
2
3
39
Co-verification Support
Formal Specifications pre
--------------------------- post
---------------------------
--------------------------------------------------
--------------------------------------
-------- ------------ ----------------------
--------------- ----------------------
------------------------
---------------------------------------------
------------------------------------------------
-- ---- --------------------------
-----------
UniTesK supports this transformation with
techniques and tools
Testable Specifications pre
--------------------------- post
---------------------------
--------------------------------------------------
--------------------------------------
-------- ------------ ----------------------
--------------- -----------------------
-----------------------
----------------------------------------------
-----------------------------------------------
--- ---- ------------------------------
-------
Software -----------------------------------
---------------- ----------------------------
----------------------- ---------------------
------------------------------
--------------------------------------------------
- -------------------------------------------
-------- ------------------------------------
--------------- -----------------------------
---------------------- ----------------------
-----------------------------
--------------------------------------------------
-
40
Engineering Problems (2)

• More than one coverage metric is needed
• Automatic extraction of coverage goals
• Enabling test designer to introduce additional
  goals

41
Several Levels of Coverage Metrics
1.2.1 1.2.2
1.1 1.2 1.3
Formal Specifications pre
--------------------------- post
---------------------------
--------------------------------------------------
--------------------------------------
-------- ------------ ----------------------
--------------- -----------------------
-----------------------
----------------------------------------------
-----------------------------------------------
--- ---- ------------------------------
-------
1.3.1 1.3.2 1.3.3
1
2
2.1 2.2
3
3.1.1 3.1.2 3.1.3
3.1 3.2
42
Definition of Coverage Goals Functionality
Branches

• Functional coverage description based on
  specification structure

post if(a b) ... branch Case 1 ...
else if(!c d) ... branch Case 2 ... else
... branch Case 3 ...
Branches Disjuncts
Case 1 a
Case 1 !a ? b
Case 2 !a ? !b ? !c ? d
Case 3 !a ? !b ? c
Case 3 !a ? !b ? !c ? !d
43
Functionality Branches in size() Method

• public class PQueueSpecification
• specification public int size ()
• reads this.?
• post
• branch Single branch
• return size items.size()

44
Functionality Branches in enq() Method

• specification public void enq (Object obj, int
  prty)
• reads obj, prty
• updates this.?
• pre return obj ! null
• post
• int i 0
• for(i 0
• i lt items.size() priorities.get(i) gt
  prty
• i
• )
• branch Single branch
• PQueueSpecification new_state
  (PQueueSpecification)_at_clone()
• new_state.items.add(i, obj)
• new_state.priorities.add(i, prty)

45
Functionality Branches in deq() Method

• specification public Object deq ()
• updates this.?
• post
• if(items.isEmpty())
• branch Empty queue
• return deq null items.isEmpty()
• else
• branch Nonempty queue
• PQueueSpecification new_state
  (PQueueSpecification)_at_clone()
• Object result new_state.items.firstElement
  ()
• new_state.items.removeFirstElement()
• new_state.priorities.removeFirstElement()
• return this.equals(new_state) deq
  result

46
Additional Coverage Goals enq()
1
0
5
2
7
4
5
5
4
3
1
1
1
1
1
1
47
Additional Coverage Goals deq()
5
5
4
3
1
1
5
4
3
1
48
Definition of Coverage Goals Marked Paths
post if(a b c)
branch Case 1 ...
if(a) mark a holds
Branches Marked Paths Disjuncts
Case 1 a holds Case 1 a
Case 1 Case 1 !a ? b
Case 1 Case 1 !a ? !b ? c
49
Marked Paths in enq() Method

• post
• int i 0
• for(i 0
• i lt items.size() priorities.get(i) gt
  prty
• i
• )
• if( items.isEmpty() )
• mark "Insertion in the empty queue"
• else if( prty gt priorities.maximum() )
• mark "Insertion in the head"
• else if( prty priorities.maximum() prty
  priorities.minimum() )
• mark "Insertion with single existing
  priority"
• else if( prty priorities.maximum() )
• mark "Insertion with maximum priority"
• else if( prty lt priorities.minimum() )
• mark "Insertion in the tail with new
  priority"
• else if( prty priorities.minimum() )

50
Marked Paths in deq() Method

• post
• if(items.isEmpty())
• branch Empty queue
• ...
• else
• if( items.size() 1 )
• mark "Single element in the queue"
• else if( !(priorities.maximum()
  priorities.get(1)) )
• mark "Single element with maximum priority,
  several elements in the queue"
• else if( priorities.toSet().size() gt 1 )
• mark "Several elements with maximum
  priority, there are other priorities"
• else
• mark "Several elements in the queue with
  the same priority"
• branch Nonempty queue

51
Test Implementation
Testable Specifications pre
--------------------------- post
---------------------------
--------------------------------------------------
--------------------------------------
-------- ------------ ----------------------
--------------- -----------------------
-----------------------
----------------------------------------------
-----------------------------------------------
--- ---- ------------------------------
-------
Test Case 1 --------------- --------------- ------
--
Test Program
Test Scenario
52
Co-verification Support
Formal Specifications pre
--------------------------- post
---------------------------
--------------------------------------------------
--------------------------------------
-------- ------------ ----------------------
--------------- ----------------------
------------------------
---------------------------------------------
------------------------------------------------
-- ---- --------------------------
-----------
Testable Specifications pre
--------------------------- post
---------------------------
--------------------------------------------------
--------------------------------------
-------- ------------ ----------------------
--------------- -----------------------
-----------------------
----------------------------------------------
-----------------------------------------------
--- ---- ------------------------------
-------
UniTesK supports this transformations with
techniques and tools
Software -----------------------------------
---------------- ----------------------------
----------------------- ---------------------
------------------------------
--------------------------------------------------
- -------------------------------------------
-------- ------------------------------------
--------------- -----------------------------
---------------------- ----------------------
-----------------------------
--------------------------------------------------
-
Test Scenario
53
Engineering Problems (3)

• Test construction technique should ensure
  coverage goals achievement
• Enabling test designer to introduce additional
  tests
• Tests should be decoupled with implementation

54
Overview of UniTesK Approach to Test
Implementation

• Test construction technique traversal of FSM
• FSM is constructed in so far that its traversal
  ensures coverage
• FSM represented implicitly as test scenario
• Implicit representation saves a lot of work
• Test scenarios can be
• Generated on the base of templates and
  specifications
• Developed manually
• Developed in mixed way
• Mediators are used to decouple test scenarios and
  implementation
• The same three ways to develop mediators

55
UniTesK Test Architecture

• From specification we can generate oracle to
  check the conformance of system behaviour
• The entire test is constructed as a test sequence
  intended to achieve some coverage
• Test sequence required is produced on-the-fly
  during test execution as a transition tour of FSM
  model

UniTesK
.N_at_T
J_at_T
CTesK
VDMTesK
Uniform Test Architecture
Uniform Specification Extension
Integration with Development Environments
Model Based Testing
56
UniTesK Test Architecture
Test sequence construction
Test Engine
Test Action Iterator
Test sequence construction
Oracle
Specification
Target system
57
Test Sequence Construction
Test Engine
Test Action Iterator
58
Engineering Problems FSM Construction (4)

• Implicit specifications are hard to resolve
• Nondeterminism
• Huge numbers of states and transitions

59
Factorization Based on Coverage Goals
Helps to cope with state explosion and
nondeterminism
I. B. Bourdonov, A. S. Kossatchev, V. V.
Kuliamin. Using Finite State Machines in Program
Testing. Programming and Computer Software, Vol.
26, No. 2, 2000, pp. 61-73
60
Implicit State Machine Description
Allows not to resolve implicit constraints Makes
factorization easier
61
State Machine Construction Based on Coverage Goals
operation domain defined by precondition
parameters
2
3
coverage goals
1
states
62
Test Sequence Construction for Implicit FSM
Test Engine
Test Action Iterator
63
Test Scenario
Test sequence construction
Test Engine
Test Action Iterator
Test Scenario
Oracle
Specification
Target system
64
Priority Queue Example enq() Coverage Goals

• if( items.isEmpty() )
• mark "Insertion in the empty queue"
• else if( prty gt priorities.maximum() )
• mark "Insertion in the head"
• else if( prty priorities.maximum() prty
  priorities.minimum() )
• mark "Insertion with single existing priority"
• else if( prty priorities.maximum() )
• mark "Insertion with maximum priority"
• else if( prty lt priorities.minimum() )
• mark "Insertion in the tail with new priority"
• else if( prty priorities.minimum() )
• mark "Insertion with minimum priority"
• else if( !priorities.contains(prty) )
• mark "Insertion in the middle with new
  priority"
• else
• mark "Insertion in the middle with existing
  priority"

States
Empty queue
Single priority is used
At least two priorities are used
At least three priorities are used
?
Arguments
At least three different priorities should be
provided
65
Priority Queue Example deq() Coverage Goals

• if(items.isEmpty())
• branch Empty queue
• else
• if( items.size() 1 )
• mark "Single element in the queue"
• else if( !(priorities.maximum()
  priorities.get(1)) )
• mark "Single element with maximum priority,
  several elements in the queue"
• else if( priorities.toSet().size() gt 1 )
• mark "Several elements with maximum priority,
  there are other priorities"
• else
• mark "Several elements in the queue with the
  same priority"

States
Empty queue
Single element in the queue
Single element with maximum priority, several
priorities
Several elements with maximum priority, several
priorities
Several elements with the single used priority
66
Priority Queue Example Analysis of Determinism
0
1
2
deq()
0 Empty queue
1 Single element in the queue
2 Several elements with single used priority
To make the behavior deterministic we should
split this state according to the number of
elements
67
Priority Queue Example Analysis of Determinism

0
1
2
3
deq()
A
0,1,2, Number of elements with maximum
priority
A Single element with maximum priority, several
priorities
To make the behavior deterministic we should
split this state according to the number of
elements with the next priority
And so on, for all priorities (by induction)
68
Priority Queue Example Resulting State

• Resulting state S int ? int ismap from
  integers to integers, wherekey is priorityvalue
  is the number of queue elements having such
  priority

69
Reference to Specification Object

• scenario public class PQueueTestScenario
• // Reference to the object under test
• public PQueueSpecification queue

70
State Construction Method

• scenario public class PQueueTestScenario
• public AbstractGenState getGenState()
• IntToIntMapGenState state new
  IntToIntMapGenState()
• for(int p PQueueSpecification.Min_Priority
• p lt queue.priorities.toSet().size()
• p
• )
• int n queue.priorities.numberOf(p)
• if( n ! 0 ) state.put(p, n)
• return state

71
Definition of Test Actions size() method

• scenario public class PQueueTestScenario
• scenario public boolean size()
• queue.size()
• return true

72
Definition of Test Actions enq() method

• scenario public class PQueueTestScenario
• scenario public boolean enq()
• Object arg new Object()
• iterate( int priority PQueueSpecification.Mi
  n_Priority
• priority lt PQueueSpecification.Max_P
  riority
• priority
• queue.priorities.toSet().size()
  lt 3
• queue.priorities.contains(prior
  ity)
• queue.priorities.numberOf(prior
  ity) lt 2
• )
• queue.enq(param, priority)
• return true

73
Definition of Test Actions deq() method

• scenario public class PQueueTestScenario
• scenario public boolean deq()
• queue.deq()
• return true

74
Using Nondeterministic FSMs Bounded Queue
add
Empty
Empty
empty
Single element
Single element
Intermediate
Intermediate
Almost full
Almost full
fill
Full
Full
remove
75
Testing Concurrency

• Fair Concurrency Axiom Concurrent execution of
  several operations is correct if and only if it
  is equivalent to somehow ordered one
• So, to test the concurrent execution of calls we
  should check that it behaves like some sequence
  of the same calls
• The system can be modeled as an ordinary FSM
• Test engine generates pairs, triples, and so on,
  of concurrent actions
• System not satisfying Fair Concurrency Axiom
  should be modeled as asynchronous FSM

76
Asynchronous FSM

• Some transitions are fired by a stimulus
• Some transitions are fired along with a reaction
• Some transitions are empty, modeling internal
  operation

/y
b/
/x
a/
a/
b/
Possible behavior input aba ouput
yyx xxyxyyyx
xyyyxy all possible outputs
xyxyyx, xyxyyxxyyx, xyyxxyyx
/y
/x
77
Co-verification Support Changes
Interface changed
???
Software -----------------------------------
-------- ------------------------------------
------- -------------------------------------
------ --------------------------------------
---
78
Engineering Problems (5)

• Tests and implementation should be decoupled
• Tests can be reused many times
• Easy regression testing
• Specification should be as abstract as possible
• Specification should be even more reusable than
  tests

79
Mediator

• Mediator decouples specification and
  implementation

Target system
80
Mediator Construction
Test Engine
Test Action Iterator
Test Scenario
Oracle
Specification
Mediator
Mediator in Extended Language
Target system
81
Open State Testing

• Mediator constructs new model state only on the
  base of new implementation state
• Requires Implementation state should be
  accessible by public fields or reliable observers
• Implies Current model state actually corresponds
  to implementation one
• Detected failure demonstrates a fault in the last
  operation
• Transition tour is sufficient to ensure
  reliability

Mediator
Target system
call
call
response
get state data
state data
construct new model state
82
Hidden State Testing

• Mediator constructs new model state on the base
  of old one and implementation call results
• Implies Current model state is actually a
  hypothesis
• Detected failure can be manifestation of a fault
  in any previously called operation
• Transition tour is insufficient to ensure
  reliability

Mediator
Target system
call
call
response
construct new model state
83
Mediator for Priority Queue

• mediator public class PQueueMediator
• // Extends specification class
• extends PQueueSpecification
• // Reference to an implementation object
• implementation public PriorityQueue target

84
Model State Synchronization Method (Open State
Testing)

• mediator public class PQueueMediator
• public void mapStateUp()
• items.clear()
• priorities.clear()
• if( target ! null )
• for(int i target._clusters.size()- 1 i
  gt 0 i--)
• Vector v (Vector)target._clusters.elemen
  tAt(i)
• for(int j 0 j lt v.size() j)
• items.add(v.elementAt(j))
• priorities.add(i)

85
Mediator Methods (Open State Testing)

• mediator public class PQueueMediator
• public int size()
• return target.size()
• public void enq(Object obj, int prty)
• target.enq(obj, prty)
• public Object deq()
• return target.deq()

86
Mediator Methods (Hidden State Testing)

• mediator public class PQueueMediator
• public int size()
• return target.size()
• public void enq(Object obj, int prty)
• target.enq(obj, prty)
• items.add(obj)
• priorities.add(prty)
• public Object deq()
• Object result target.deq()

87
Test Scenario Initialization

• scenario public class PQueueTestScenario
• public PQueueTestScenario()
• setTestEngine ( new DeterministicFSM_TestEngin
  e() )
• PQueueMediator.initClassState()
• queue PQueueMediator.create(new
  PriorityQueue())
• queue.attachOracle()

88
UniTesK Practice Overview

• UniTesK tools
• UniTesK history
• Training courses
• QUTILUI project
• Other case studies

89
UniTesK Tools
UniTesK
.N_at_T
J_at_T
CTesK
VDMTesK
Uniform Test Architecture
Uniform Specification Extension
Integration with Development Environments
Model Based Testing
90
UniTesK History

• pre-UniTesK
• 1994 1996ISP RAS Nortel Networks contract
  onfunctional test suite development for Switch
  Operating System kernel
• Few hundreds of bugs found in the OS kernel,
  which had been 10 years in use
• About 600K lines of Nortel code tested by
  2001But failed to be introduced in Nortel
  processes

91
UniTesK Tools History

• 1999-2000
• Conception
• 2001
• J_at_T Prototype
• CTesK Lite
• 2002
• VDM TesK
• J_at_T Product
• 2003
• J_at_T Suite 1.2 (Java and C testing)
• CTesK Full
• .N_at_T

92
Sqrt Specification in J_at_va and Extended C

• class SqrtSpecification
• specification static double sqrt(double x)
• reads x
• pre return x gt 0
• post
• if(x 0)
• branch "Zero argument"
• return sqrt 0
• else
• branch "Positive argument"
• return sqrt gt 0
• Math.abs((sqrtsqrt-x)/x
• lt epsilon

specification double SQRT(double x) reads
(double)x pre return x gt 0. coverage
ZP if(x 0.) return (ZERO, "Zero
argument") else return (POS, "Positive
argument") post if(coverage(ZP,
ZERO)) return SQRT 0. else
return SQRT gt 0.
abs((SQRTSQRT - x)/x) lt
epsilon
operation signature declaration
functional branches definition
postcondition
access constraints
precondition
93
Training Courses
CTesK training was conducted for Tercom
(St.-Petersburg, Russia), Saarland University
(Germany) J_at_T training was conducted for
Systematic Software Engineering (Denmark)
94
QUTILUI Project

• GoalRedesign of SOS Queue Manipulation Utilities
  Subsystem
• Activities
• Requirements elicitation
• Specification development
• Specification review
• Architecture design
• Component design
• Implementation
• Testing and debugging

95
QUTILUI Project Results
----------- ----------- ----------- -----------
- - - - - - - - - - - - - - - - - - - - - - - - -
- - -

• Bugs removed
• No bugs found after the project end!
• 25 decrease of implementation size
• Design documentation appeared
• And it became actual!
• Tests demonstrated conformance with requirements

-------- -------- ----
96
Other Examples of UniTesK Usage

• IPv6 implementations
• Microsoft Research
• Mobile IPv6 (in Windows CE 4.1)
• mpC Workshop
• Debug API
• mpC expression static and dynamic semantics
• Optimization units in Intel compilers
• UniTesK tools
• J_at_T test system runtime support
• Components of J_at_va translator
• CTesK abstract types library
• Lanit-Tercom
• IPv6 implementation
• DSP software

97
References

1. B. Bourdonov, A.S. Kossatchev, V.V. Kuliamin,
   A.K. Petrenko,. UniTesK Test Suite Architecture//
   Proceedings of FME2002 conference, Copenhagen,
   Denmark, LNCS, No. 2391, 2002, pp. 77-88.
2. I.B.Burdonov, A.V.Demakov, A.A.Jarov,
   A.S.Kossatchev, V.V.Kuliamin, A.K.Petrenko,
   S.V.Zelenov. J_at_va extension of Java for
   real-life specification and testing // Proc. of
   Andrei Ershov Fourth International Conference
   PCI01, Novosibirsk, LNCS, Vol. 2244, 2001,
   pp.301-308.
3. A.K. Petrenko, V.V. Kuliamin, I.B. Bourdonov,
   A.S. Kossatchev. Experiences in using testing
   tools and technology in real-life applications//
   Proceedings of SETT01, India, Pune, 2001
4. A.K.Petrenko, V.V.Kuliamin, I.B.Burdonov,
   A.V.Demakov, A.A.Jarov, A.S.Kossatchev,
   S.V.Zelenov. J_at_va extension of Java for
   real-life specification and testing// Proceedings
   of PSI01, Novosibirsk, LNCS 2244, 2001,
   pp.301-308.
5. A.K.Petrenko. Specification Based Testing
   Towards Practice. Proceedings of PSI01,
   Novosibirsk, LNCS 2244, 2001, pp.157-162.
6. A.Petrenko, A.Vorobiev. Industrial Experience in
   Using Formal Methods for Software Development in
   Nortel Networks// Proceedings of Testing Computer
   Software Conference TCS 2000, Washington, June,
   2000.
7. V.V. Kuliamin, I.B. Bourdonov, A.S. Kossatchev.
   Using Finite State Machines in Program Testing//
   Programming and Computer Software, Vol. 26, No.
   2, 2000, pp. 61-73.
8. I. Bourdonov, A. Kossatchev, A. Petrenko, and D.
   Galter. KVEST Automated Generation of Test
   Suites from Formal Specifications// Proceedings
   of World Congress of Formal Methods, Toulouse,
   France, LNCS, No. 1708, 1999, pp. 608-621

98
Thank you!