Software Testing and Quality Assurance

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Software Testing and Quality Assurance

• Lecture 13 - Planning for Testing (Chapter 3, A
  Practical Guide to Testing Object-Oriented
  Software)

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Lecture Outline

• To be able to plan a test process that complement
  the development process.

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Introduction

• Testing requires considerable resources.
  Effective utilization of those resources
  requires good planning and good management.
• Planning at technical level is guided by
  templates that are instantiated as needed by
  developers
• IEEE test plan standard
• Basic testing process
• Test early, test often, test enough.

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A Development process overview

• A process is a continuous series of activities
  that convey you to an end.
• Four main activities of software development
• Analysis (domain and application analysis)
  focuses on understanding the problem and defining
  the requirements for the software portions of the
  system
• Design (architectural design, subsystem and
  package design, class design, and algorithm
  design) focuses on solving the problem in software

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A Development process overview (cont...)

• Implementation (class implementation and
  integration) focuses on translating the design
  into executable code
• Testing (basic unit testing, integrated units
  testing, subsystem testing, system testing)
  focuses on ensuring that inputs produce the
  desired results as specified by the requirements.
• Maintenance focuses on bug repairs and
  enhancements.

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A Development process overview (cont...)

• Development models Evolutionary, incremental
  (our focus), spiral, concurrent.
• Under an increment development process, a system
  is developed as a sequence of increments.
• An increment can be a deliverable,
• including models, documentation, and code, which
  provides some of the functionality required by
  the system.

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A Development process overview (cont...)

• The products developed in one increment feeds
  into the development of the next increment.
• The final increment is delivers a deployable
  system that meets all requirements.
• Increments can be developed in sequence or one or
  more can be developed concurrently.

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A Development process overview (cont...)

• In each increment developers analyze, design,
  code, and test as needed.
• Developers have to perform these activities
  repeatedly in building an increment
• because they find errors in previous work
  (incremental, iterative development process).

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A Development process overview (cont...)
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A Development process overview (cont...)

• Object-oriented development is particularly well
  suited to evolutionary development
• because OO analysis, design and implementation
  entail the successive refinement of a single
  model.
• In OO analysis, we understand a problem by
  modeling it in terms of objects and classes of
  objects, their relationships and responsibilities.

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A Development process overview (cont...)

• In OO design, we solve the problem by
  manipulating those same objects and relationships
  identified in analysis and
• introducing solution-specific classes, objects,
  relationships, and responsibilities.
• Testing should also be done in every increment.
  Regression tests must be run between increments
  and within iterations.

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Example Incremental, Iterative Development Plan
for Brickles
Increment Iteration
Present user interface showing puck bouncing in window 1.a Domain analysis Construct class diagrams 1.b Application analysis Construct class diagrams and sate diagrams 1.c Design Study MFC and animation. 1.d Design Complete class diagram for puck bouncing in a window 1.e Implementation Code puck bouncing in window 1.f Testing Test the code for puck bouncing in window
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Example Incremental, Iterative Development Plan
for Brickles (cont...)
Increment Iteration
Move paddle in window and detect collisions 2.a Application analysis Add details of Paddle control and collisions to class diagrams, other diagrams 2.b Design Design Paddle and collision classes. 2.c Implementation Code Paddle classes incrementally from MovsbleSprite and collision class from exception.
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Example Incremental, Iterative Development Plan
for Brickles (cont...)
Increment Iteration
Display brick pile and detect collisions. 1.a Application analysis Add collections of sprites to class diagram 1.b. Design Design collision detection algorithm. 1.c Implementation Code Brickpile class by aggregating collection class.
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Example Incremental, Iterative Development Plan
for Brickles (cont...)
Increment Iteration
4. Add supply of pucks and detect end of match 1.a Design End of match algorithm to use exceptions to detect endOfMatch 1.b. Implementation PuckSupply class.
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A Testing process overview

• Development and testing are two distinct but
  intimately related processes. Their activities
  overlap when test cases have to be designed,
  coded, and executed.
• The roles of development and testing
  functionality are usually assigned to different
  people.

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A Testing process overview
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A Testing process overview testability

• Testability is related to how easily you can
  evaluate the results of the tests.

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A Testing process overview test cases and test
suites

• The basic component of testing is a test case.
• A test case is a pair (input, expected result)
• Input is a description of an input to the
  software under test.
• Expected result is a description of the output
  that the software should exhibit for the
  associated input.
• Input and expected result may not be simple data
  values, they can be arbitrarily complex.

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A Testing process overview test cases and test
suites (cont...)

• A test case execution is a running of the
  software that provides the input specified in the
  test case and
• observes the results and compares them to those
  specified by the test case.

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A Testing process overview test cases and test
suites (cont...)

• Test suites have some sort of organization based
  on the kinds of test cases, e.g.
• system capacity test suites, typical uses of the
  system suite, etc.
• Main issues in test suite
• correctness, observability of results, and
  adequacy.

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A Testing process overview STEP testing technique

• Analysis The product to be tested is examined to
  identify any special features that must receive
  particular attention and to determine the test
  cases that should be constructed.
• Construction the artifacts that are needed for
  testing are created. Test cases identified during
  analysis are translated into programming
  languages and scripting languages.

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A Testing process overview STEP testing technique

• Execution and evaluation the results are
  examined to determine whether the software passed
  the test suite or failed it.

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Key points

• Basic testing process Test early, test often,
  test enough.
• Development and testing are two distinct but
  intimately related processes.
• The basic component of testing is a test case
  (pair of input and expected result)
• STEP testing technique analysis, construction,
  and execution and evaluation.