Testing Techniques

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Testing Techniques

• Software Testing Module (0721430)
• Dr. Samer Hanna

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Testing Techniques

• Testing consists of the following steps (Harrold,
  2000)
• Designing test data
• Executing the system under test with those test
  cases
• Examining the results of the execution and
  comparing them with the expected results.

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Test Data and Test Cases

• Program to be tested is executed using
  representative data samples or test data and the
  results are compared with the expected results.
• Test cases include input test data and the
  expected output for each input.

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Exhaustive Testing

• It is impossible to test a piece of code, such as
  a method or function, with every possible input
  to check if the code produces the expected
  output.
• This is known as exhaustive testing
• However, there are many testing techniques that
  are used to design test data such as boundary
  value testing and equivalent partitioning.

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Testing Techniques Categories

• Testing techniques can be categorized along
  various dimensions depending on
• 1) The availability of the source code
• Testing techniques can be categorized to
  black-box or white-box testing according to the
  availability of the source code

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White-Box testing

• If the source code of the system under test is
  available then the test data is based on the
  structure of this source code (Jorgensen, 2002).
• Examples of white-box testing are path testing
  and data flow testing (Jorgensen, 2002).

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Black-Box testing

• If the source code is not available then test
  data is based on the function of the software
  without regard to how it was implemented
  (Jorgensen, 2002). Examples of black-box testing
  are boundary value testing (Jorgensen, 2002) and
  equivalence partitioning (Myers, 1979).

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2) The role of testing

• Testing techniques can also be categorized
  according to the type of testing (Sommerville,
  2004) which is based on the role or goal of this
  test some testing techniques belong to the
  validation testing and others belong to the
  defect or fault-based testing

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Validation testing

• This kind of testing is intended to show that the
  software meets the customer requirement. In
  validation testing each requirement must be
  tested by at least one test case.
• An example of a testing technique that belong to
  this type of testing is specification-based
  testing where test data are generated from
  state-based specifications that describes what
  functions the software is supposed to provide.

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Validation testing

• If the specification is written by a model such
  as UML and the test case generation is based on
  that model, then the testing is called
  model-based testing (Toth et al. 2003), This
  testing also belong to validation testing.

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Defect testing (fault-based testing or negative
testing)

• This type of testing is intended to detect faults
  (bugs or defects) in the software system rather
  than testing the functional use of the system
  like validation testing (Sommerville, 2004).
• Examples of the testing techniques that belong to
  this type of testing include boundary value
  based robustness testing (Jargensen, 2002), and
  syntax testing (Beizer, 1990).

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Defect testing

• Defect testing contribute to the assessment of
  the following quality attributes robustness,
  fault-tolerance and security

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3) The level of testing

• Testing techniques can be distinguished according
  to the scope or level of a test
• Unit testing
• Testing individual or independent software unit
  (IEEE, 1990). A unit is defined as the smallest
  piece of software that can be independently
  tested (Beizer, 1990).

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The level of testing

• Integration testing
• This kind of testing is used to test the
  interaction between the units that was already
  tested using Unit testing (IEEE, 1990).
• System testing
• This kind of testing is conducted on a complete
  and integrated software system to evaluate its
  compliance with its specified requirements (IEEE,
  1999).

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4) The quality attribute or system behavior

• Testing techniques can be distinguished according
  to the quality attribute or system behavior being
  tested such as performance, robustness, and
  correctness. Examples of these kinds of testing
  are

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Performance testing

• Used to assess the performance quality attribute
  of a system or component and is defined as
• Testing conducted to evaluate the compliance of
  a system or components with specified performance
  requirements (IEEE, 1990).
• A performance requirement may include speed with
  which a given function must be performed (IEEE,
  1990).

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Robustness testing

• Robustness testing is used to assess the
  robustness quality attribute of a software
  system. Robustness testing include some testing
  techniques such as boundary value based
  robustness testing technique (Jorgensen, 2002)
• Robustness testing is defined as
• Testing how a system or software component reacts
  when the environment shows unexpected behavior.

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Security testing

• Used to assess the security quality attribute of
  a system or component by testing if an intruder
  can read or modify the system data or
  functionality.

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Load testing

• Used to test if a system or component can cope
  with heavy loads such as being used by many users
  at the same time.

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Relation between categories

• The above four categories or dimensions (the
  availability of source code, the role of testing,
  the level of testing, and the quality attribute
  or system behaviour) of testing techniques are
  not disjoint for example the boundary value
  based robustness testing (Jorgensen, 2002)
  belongs to the following types of testing
  black-box testing, unit testing and fault-based
  testing at the same time. Other black-box testing
  techniques can also be considered fault-based
  testing techniques such as syntax testing
  (Beizer, 1990).

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Questions?