CoWTeSt: A Cost Weighted Test Strategy

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CoWTeSt A Cost Weighted Test Strategy
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Test Planning Strategy

• Objectives
• Decide which and how many test cases should be
  executed.
• Give a practical help to managers to support test
  planning and evaluate the impact of testing the
  phase on the cost of the final product.

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Features

• (Exclusively) UML based It uses the Use Cases
  and Interaction diagrams developed during
  analysis and design phases
• Cowtest strategy development of a systematic
  method for UML design-based integration test of
  complex system.
• Based exclusively on the use of UML diagrams
  
• immediately usable from industries already using
  UML (no additional modeling or design costs)
• analysis can be started soon, and done
  contemporarily with project development
• Different strategies for test cases selection

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Presentation Scheme
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CoWTeSt A Cost Weighted Test Strategy

• Weighted Tree Derivation
• Starting from the main UCD the UCs and SDs are
  organized in a sort of hierarchical tree
• Deduce the Critical Profile annotate every arch
  with a value representing the importance of the
  associate node (be it a UC or a SD scenario)
• Test Case Derivation apply UIT for test
  derivation

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Integration Stage

• The first integration stage is represented by the
  main UC and the SDs (if any), which are children
  of this node (hence they are at level 2 of the
  tree).
• The i-th integration stage is represented by the
  UCs positioned in at i-th level of the tree and
  every SDs, children of these nodes, situated at
  i1-th level.
• NOTE In the i-th integration stage the SDs at
  level i1 are considered, because they represent
  the interaction between the different components
  that realize the functionalities described in the
  UCs at i-th level of the tree.

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3rd Integration Stage
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Test Case Selection

• For every node, the product of all the nodes
  weights on the complete path from the root to
  this node represents its final weight.

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Test Case Selection
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80 Functional Coverage
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Selection of leaves for different coverage levels
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Selection of leaves for different coverage levels
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Presentation Scheme
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Use Interaction Test methodology

• A method to systematically derive Integration
  Test suites from UML diagrams
• Use case diagrams
• Sequence (Interaction) diagrams
• Class diagrams
• Incremental test strategy (over the Use Case
  organizational structure)
• Seven steps involved

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Step 1 UML design analysis and search of
relevant Use Cases
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Step 2/1 Analysis of Sequence and Class diagrams
involved in the selected Use Case
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Step 2/2 Class diagram analysis
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Step 3 Test Units definition

• Test Units those system units separately
  testable for exercising a possible use of system
• Test Units
• DecisionModel, Decision, GoalModel, Goal.

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Step 4 Research of Settings and Interactions
Categories

• - SettingsCategories parameters and inputs
  relevant in the Test Unit.
• - InteractionsCategories objects interactions,
  exchanged messages.
• Categories
• DecisionModel
• Settings _decisions
• Interactions DecisionModel()
• getDecisions()
• Decision
• Interactions
• Decision(nameString,priorityint)
• GetName()
• GetPriority() ............

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Step 5 Test Specification construction

• For each identified category, we consider all its
  possible values and constraints.

Test Specification DecisionModel Settings
Interactions _decisions
getDecisions() Naming Opening a new
file Storage Opening a saved
file Modularity After a modification and
before saving Inheritance After a
modification and after saving Stereotypes
DecisionModel() Relationship..
Class constructor
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Step 6 Search of Message Sequences and Test Case
definition

• Message Sequences set of Messages (in temporal
  order) , involved in a SD, used by objects to
  define and elaborate specific functionalities.

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Step 6 Search of Message Sequences and Test Case
definition

• Test Case is constructed, from a Test
  Specification, for each possible combination of
  choices of every category involved in a Message
  Sequence

Test Case getDecisions() getName()/getPriority(
) Opening a saved file _decisions
Naming Note Such a Test Case must be
repeated for all possible values of _decisions
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Step 7 Definition of UseCase Test Suite and
Incremental Construction of TestFrame
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Cow_Suite Cow pluS UIT Environment

• Tool for automating
• Test cases derivation, from UIT
• Test management strategy, from COWTeST
• Uses UML diagrams already developed for the
  analysis and design phase ? no additional effort
  or information.
• Rational Rose environment

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Cow_Suite Architecture

• Uses REI, Rational Rose Extensibily Interface.
• Composed by six different components
• MDL Analyser
• Test Tree Generator
• Weights Manager
• Test Case Generator
• Test Case Builder
• Test Case Checker
• Graphics interface organized in three tabs
• CowTree
• UIT Structure
• Test Specification

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1.MDL Analyser

• Analysis of the .mdl file of Rose
• Search the information necessary to apply test
  selection strategy
• Actors and Use Cases
• Sequence diagrams and their messages
• Classes with attributes and methods
• Activity diagrams
• The information is passed as the input to the
  next component.

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2.Test Tree Generator

• All the UCDs and SDs from .mdl file are organized
  in a hierarchical tree
• using the explicit diagrams links or using the
  UC associations and classes relations
• To each node we associate
• Level identification number
• Default weight
• such that the sum of this weight plus the
  weights
• associated to all its brothers is equal to
  1.

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3.Weights Manager

• Interacts with the user for
• Assigning the real weight to each node
• Selecting directly a node
• Selecting a level number
• Check that the sum of the user assigned weights
  of a level nodes is equal to 1.
• Choosing the criterion for test case selection
• Fixing the maximum number of test cases to be
  executed
• Fixing the percentage of functionalities to be
  covered.

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4.Test Case Generator

• queries the user for the deepest integration
  level he/she is interested in and calculate the
  final weight of every leaf.
• implements the UIT method for test generation
• associates to each SD its test cases organized in
  a hierarchical manner.
• calculates and visualizes the number of test
  cases for each SD depending on the chosen
  selection criterion.
• associates to each SD the frames of the test
  cases that should be instantiated.

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Test Case Frame

• TEST CASE 8.2
• Description
• PreCondition
• Test Case 7
• Flow of event
• getEnterpriseForSourceAddress(caller)
• else
• routingResult doLRQ(caller, callee, Enterprise,
  callcase,AccessAgent, BGAResult)
• Categories
• SettingsCategories
• PEnterprise
• Callee
• BGAResult
• InteractionsCategories
• getEnterpriseForSourceAddress
• doLRQ
• PostCondition
• Comment

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5.Test Case Builder

• Interaction with the user for test case
  implementation
• For the necessary parameters
• Adding and removing categories
• Changing operations value or even test cases
  structure.
• The changes involving the UML design are finally
  saved in a new file.

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6. Test Case Checker

• The tool maintains information about the test
  cases generation.
• This module will realize the comparison of
  different versions of the same .mdl file.
• The discovered differences, like, for example,
  the existence of new test cases or changes in
  those already generated, are saved into a
  separate file.
• The evaluation of the cost and impact required
  for the updates to the test plan with respect to
  the official version is derived analyzing this
  file.

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References

• F. Basanieri, A. Bertolino, A Practical Approach
  to UML-based Derivation of Integration Tests,
  QWE2000, Bruxelles, 20-24 November, 3T.
• Basanieri, F., Bertolino, A., Marchetti, E.,
  CoWTeSt A Cost Weighed Test Strategy, accepted
  for ESCOM-SCOPE 2001, London, England, 2-4 April
  2001.
• Basanieri, F., Bertolino, A., Marchetti, E.,
  Ribolini, A., An Automated Test Strategy Based
  on UML Diagrams submitted to ICSE 2001 WAPATV
  workshop.
•