SOFTWARE QUALITY ASSURANCE
A. Concepts and Definitions
Software Quality Assurance (SQA) is defined as a planned and
systematic approach to the evaluation of the quality of and
adherence to software product standards, processes, and
procedures. SQA includes the process of assuring that
standards and procedures are established and are followed
throughout the software acquisition life cycle. Compliance
with agreed-upon standards and procedures is evaluated
through process monitoring, product evaluation, and audits.
Software development and control processes should include
quality assurance approval points, where an SQA evaluation
of the product may be done in relation to the applicable
standards.
B. Standards and Procedures
Establishing standards and procedures for software
development is critical, since these provide the framework
from which the software evolves. Standards are the
established criteria to which the software products are
compared. Procedures are the established criteria to which
the development and control processes are compared.
Standards and procedures establish the prescribed methods
for developing software; the SQA role is to ensure their
existence and adequacy. Proper documentation of standards
and procedures is necessary since the SQA activities of
process monitoring, product evaluation, and auditing rely
upon unequivocal definitions to measure project compliance.
Types of standards include:
Documentation Standards specify form and content for
planning, control, and product documentation and provide
consistency throughout a project. The NASA Data Item
Descriptions (DIDs) are documentation standards (see
Appendix B).
Design Standards specify the form and content of the
design product. They provide rules and methods for
translating the software requirements into the software
design and for representing it in the design
documentation.
Code Standards specify the language in which the code
is to be written and define any restrictions on use of
language features. They define legal language
structures, style conventions, rules for data structures
and interfaces, and internal code documentation.
Procedures are explicit steps to be followed in carrying out
a process. All processes should have documented procedures.
Examples of processes for which procedures are needed are
configuration management, nonconformance reporting and
corrective action, testing, and formal inspections.
If developed according to the NASA DID, the Management Plan
describes the software development control processes, such
as configuration management, for which there have to be
procedures, and contains a list of the product standards.
Standards are to be documented according to the Standards
and Guidelines DID in the Product Specification. The
planning activities required to assure that both products
and processes comply with designated standards and
procedures are described in the QA portion of the Management
Plan.
C. Software Quality Assurance Activities
Product evaluation and process monitoring are the SQA
activities that assure the software development and control
processes described in the project's Management Plan are
correctly carried out and that the project's procedures and
standards are followed. Products are monitored for
conformance to standards and processes are monitored for
conformance to procedures. Audits are a key technique used
to perform product evaluation and process monitoring.
Review of the Management Plan should ensure that appropriate
SQA approval points are built into these processes.
Product evaluation is an SQA activity that assures standards
are being followed. Ideally, the first products monitored
by SQA should be the project's standards and procedures. SQA
assures that clear and achievable standards exist and then
evaluates compliance of the software product to the
established standards. Product evaluation assures that the
software product reflects the requirements of the applicable
standard(s) as identified in the Management Plan.
Process monitoring is an SQA activity that ensures that
appropriate steps to carry out the process are being
followed. SQA monitors processes by comparing the actual
steps carried out with those in the documented procedures.
The Assurance section of the Management Plan specifies the
methods to be used by the SQA process monitoring activity.
A fundamental SQA technique is the audit, which looks at a
process and/or a product in depth, comparing them to
established procedures and standards. Audits are used to
review management, technical, and assurance processes to
provide an indication of the quality and status of the
software product.
The purpose of an SQA audit is to assure that proper control
procedures are being followed, that required documentation
is maintained, and that the developer's status reports
accurately reflect the status of the activity. The SQA
product is an audit report to management consisting of
findings and recommendations to bring the development into
conformance with standards and/or procedures.
D. SQA Relationships to Other Assurance Activities
Some of the more important relationships of SQA to other
management and assurance activities are described below.
1. Configuration Management Monitoring
SQA assures that software Configuration Management (CM)
activities are performed in accordance with the CM plans,
standards, and procedures. SQA reviews the CM plans for
compliance with software CM policies and requirements and
provides follow-up for nonconformances. SQA audits the CM
functions for adherence to standards and procedures and
prepares reports of its findings.
The CM activities monitored and audited by SQA include
baseline control, configuration identification,
configuration control, configuration status accounting, and
configuration authentication. SQA also monitors and audits
the software library. SQA assures that:
Baselines are established and consistently maintained
for use in subsequent baseline development and control.
Software configuration identification is consistent and
accurate with respect to the numbering or naming of
computer programs, software modules, software units, and
associated software documents.
Configuration control is maintained such that the
software configuration used in critical phases of
testing, acceptance, and delivery is compatible with the
associated documentation.
Configuration status accounting is performed accurately
including the recording and reporting of data reflecting
the software's configuration identification, proposed
changes to the configuration identification, and the
implementation status of approved changes.
Software configuration authentication is established by
a series of configuration reviews and audits that exhibit
the performance required by the software requirements
specification and the configuration of the software is
accurately reflected in the software design documents.
Software development libraries provide for proper
handling of software code, documentation, media, and
related data in their various forms and versions from the
time of their initial approval or acceptance until they
have been incorporated into the final media.
Approved changes to baselined software are made
properly and consistently in all products, and no
unauthorized changes are made.
2. Verification and Validation Monitoring
SQA assures Verification and Validation (V&V) activities by
monitoring technical reviews, inspections, and walkthroughs.
The SQA role in formal testing is described in the next
section. The SQA role in reviews, inspections, and
walkthroughs is to observe, participate as needed, and
verify that they were properly conducted and documented.
SQA also ensures that any actions required are assigned,
documented, scheduled, and updated.
Formal software reviews should be conducted at the end of
each phase of the life cycle to identify problems and
determine whether the interim product meets all applicable
requirements. Examples of formal reviews are the
Preliminary Design Review (PDR), Critical Design Review
(CDR), and Test Readiness Review (TRR). A review looks at
the overall picture of the product being developed to see if
it satisfies its requirements. Reviews are part of the
development process, designed to provide a ready/not-ready
decision to begin the next phase. In formal reviews, actual
work done is compared with established standards. SQA's
main objective in reviews is to assure that the Management
and Development Plans have been followed, and that the
product is ready to proceed with the next phase of
development. Although the decision to proceed is a
management decision, SQA is responsible for advising
management and participating in the decision.
An inspection or walkthrough is a detailed examination of a
product on a step-by-step or line-of-code by line-of-code
basis to find errors. For inspections and walkthroughs, SQA
assures, at a minimum, that the process is properly
completed and that needed follow-up is done. The inspection
process may be used to measure compliance to standards.
3. Formal Test Monitoring
SQA assures that formal software testing, such as acceptance
testing, is done in accordance with plans and procedures.
SQA reviews testing documentation for completeness and
adherence to standards. The documentation review includes
test plans, test specifications, test procedures, and test
reports. SQA monitors testing and provides follow-up on
nonconformances. By test monitoring, SQA assures software
completeness and readiness for delivery.
The objectives of SQA in monitoring formal software testing
are to assure that:
The test procedures are testing the software
requirements in accordance with test plans.
The test procedures are verifiable.
The correct or "advertised" version of the software is
being tested (by SQA monitoring of the CM activity).
The test procedures are followed.
Nonconformances occurring during testing (that is, any
incident not expected in the test procedures) are noted
and recorded.
Test reports are accurate and complete.
Regression testing is conducted to assure
nonconformances have been corrected.
Resolution of all nonconformances takes place prior to
delivery.
Software testing verifies that the software meets its
requirements. The quality of testing is assured by
verifying that project requirements are satisfied and that
the testing process is in accordance with the test plans and
procedures.
E. Software Quality Assurance During the Software Acquisition Life Cycle
In addition to the general activities described in
subsections C and D, there are phase-specific SQA activities
that should be conducted during the Software Acquisition
Life Cycle. At the conclusion of each phase, SQA
concurrence is a key element in the management decision to
initiate the following life cycle phase. Suggested
activities for each phase are described below.
1. Software Concept and Initiation Phase
SQA should be involved in both writing and reviewing the
Management Plan in order to assure that the processes,
procedures, and standards identified in the plan are
appropriate, clear, specific, and auditable. During this
phase, SQA also provides the QA section of the Management
Plan.
2. Software Requirements Phase
During the software requirements phase, SQA assures that
software requirements are complete, testable, and properly
expressed as functional, performance, and interface
requirements.
3. Software Architectural (Preliminary) Design Phase
SQA activities during the architectural (preliminary) design
phase include:
Assuring adherence to approved design standards as
designated in the Management Plan.
Assuring all software requirements are allocated to
software components.
Assuring that a testing verification matrix exists and
is kept up to date.
Assuring the Interface Control Documents are in
agreement with the standard in form and content.
Reviewing PDR documentation and assuring that all
action items are resolved.
Assuring the approved design is placed under
configuration management.
4. Software Detailed Design Phase
SQA activities during the detailed design phase include:
Assuring that approved design standards are followed.
Assuring that allocated modules are included in the
detailed design.
Assuring that results of design inspections are
included in the design.
Reviewing CDR documentation and assuring that all
action items are resolved.
5. Software Implementation Phase
SQA activities during the implementation phase include the
audit of:
Results of coding and design activities including the
schedule contained in the Software Development Plan.
Status of all deliverable items.
Configuration management activities and the software
development library.
Nonconformance reporting and corrective action system.
6. Software Integration and Test Phase
SQA activities during the integration and test phase
include:
Assuring readiness for testing of all deliverable
items.
Assuring that all tests are run according to test plans
and procedures and that any nonconformances are reported
and resolved.
Assuring that test reports are complete and correct.
Certifying that testing is complete and software and
documentation are ready for delivery.
Participating in the Test Readiness Review and assuring
all action items are completed.
7. Software Acceptance and Delivery Phase
As a minimum, SQA activities during the software acceptance
and delivery phase include assuring the performance of a
final configuration audit to demonstrate that all
deliverable items are ready for delivery.
8. Software Sustaining Engineering and Operations Phase
During this phase, there will be mini-development cycles to
enhance or correct the software. During these development
cycles, SQA conducts the appropriate phase-specific
activities described above.
F. Techniques and Tools
SQA should evaluate its needs for assurance tools versus
those available off-the-shelf for applicability to the
specific project, and must develop the others it requires.
Useful tools might include audit and inspection checklists
and automatic code standards analyzers.
source: http://jira.atlassian.com
