2.4 Software construction  (Page 6/6)

• Techniques for creating understandable source code, including naming and source code layout
• Use of classes, enumerated types, variables, named constants, and other similar entities
• Use of control structures
• Handling of error conditions—both planned errors and exceptions (input of bad data, for example)
• Prevention of code-level security breaches (buffer overruns or array index overflows, for example)
• Resource usage via use of exclusion mechanisms and discipline in accessing serially reusable resources (including threads or database locks)
• Source code organization (into statements, routines, classes, packages, or other structures)
• Code documentation
• Code tuning

Construction testing

Construction involves two forms of testing, which are often performed by the software engineer who wrote the code:

• Unit testing
• Integration testing

The purpose of construction testing is to reduce the gap between the time at which faults are inserted into the code and the time those faults are detected. In some cases, construction testing is performed after code has been written. In other cases, test cases may be created before code is written.

Construction testing typically involves a subset of types of testing. For instance, construction testing does not typically include system testing, alpha testing, beta testing, stress testing, configuration testing, usability testing, or other, more specialized kinds of testing.

Two standards have been published on the topic: IEEE Std 829-1998, IEEE Standard for Software Test Documentation and IEEE Std 1008-1987, IEEE Standard for Software Unit Testing.

Reuse

Implementing software reuse entails more than creating and using libraries of assets. It requires formalizing the practice of reuse by integrating reuse processes and activities into the software life cycle. However, reuse is important enough in software construction that it is included here as a topic.

The tasks related to reuse in software construction during coding and testing are:

• The selection of the reusable units, databases, test procedures, or test data
• The evaluation of code or test reusability
• The reporting of reuse information on new code, test procedures, or test data

Construction quality

Numerous techniques exist to ensure the quality of code as it is constructed. The primary techniques used for construction include:

• Unit testing and integration testing
• Test-first development
• Code stepping
• Use of assertions
• Debugging
• Technical reviews
• Static analysis (IEEE1028)

The specific technique or techniques selected depend on the nature of the software being constructed, as well as on the skills set of the software engineers performing the construction.

Construction quality activities are differentiated from other quality activities by their focus. Construction quality activities focus on code and on artifacts that are closely related to code: small-scale designs - as opposed to other artifacts that are less directly connected to the code, such as requirements, high-level designs, and plans.

Integration

A key activity during construction is the integration of separately constructed routines, classes, components, and subsystems. In addition, a particular software system may need to be integrated with other software or hardware systems.

Concerns related to construction integration include planning the sequence in which components will be integrated, creating scaffolding to support interim versions of the software, determining the degree of testing and quality work performed on components before they are integrated, and determining points in the project at which interim versions of the software are tested.

References:

http://en.wikipedia.org/wiki/Software_development, http://ocw.mit.edu/OcwWeb/Electrical-Engineering-and-Computer-Science/6-171Fall2003/CourseHome/,http://www.cs.cornell.edu/courses/cs501/2008sp/, http://www.comp.lancs.ac.uk/computing/resources/IanS/SE7/,http://www.ee.unb.ca/kengleha/courses/CMPE3213/IntroToSoftwareEng.htm, http://www.generaldigital.com/software_services/qualifications.htm, etc...