What is 'Software
Quality Assurance'?
Software QA involves the entire software development PROCESS - monitoring and
improving the process, making sure that any agreed-upon standards and
procedures are followed, and ensuring that problems are found and dealt with.
It is oriented to 'prevention'.
What is 'Software Testing'?
Testing involves operation of a system or application under controlled
conditions and evaluating the results (eg, 'if the user is in interface A of
the application while using hardware B, and does C, then D should happen'). The
controlled conditions should include both normal and abnormal conditions.
Testing should intentionally attempt to make things go wrong to determine if
things happen when they shouldn't or things don't happen when they should. It
is oriented to 'detection'.
- Organizations vary considerably in how they assign responsibility
for QA and testing. Sometimes they're the combined responsibility of one
group or individual. Also common are project teams that include a mix of
testers and developers who work closely together, with overall QA
processes monitored by project managers. It will depend on what best fits
an organization's size and business structure.
What are some recent major computer system failures
caused by software bugs?
- In March of 2002 it was reported that software bugs in Britain's
national tax system resulted in more than 100,000 erroneous tax
overcharges. The problem was partly attibuted to the difficulty of testing
the integration of multiple systems.
- A newspaper columnist reported in July 2001 that a serious flaw
was found in off-the-shelf software that had long been used in systems for
tracking certain U.S.
nuclear materials. The same software had been recently donated to another
country to be used in tracking their own nuclear materials, and it was not
until scientists in that country discovered the problem, and shared the
information, that U.S.
officials became aware of the problems.
- According to newspaper stories in mid-2001, a major systems
development contractor was fired and sued over problems with a large
retirement plan management system. According to the reports, the client
claimed that system deliveries were late, the software had excessive
defects, and it caused other systems to crash.
- In January of 2001 newspapers reported that a major European
railroad was hit by the aftereffects of the Y2K bug. The company found
that many of their newer trains would not run due to their inability to
recognize the date '31/12/2000'; the trains were started by altering the
control system's date settings.
- News reports in September of 2000 told of a software vendor
settling a lawsuit with a large mortgage lender; the vendor had reportedly
delivered an online mortgage processing system that did not meet
specifications, was delivered late, and didn't work.
- In early 2000, major problems were reported with a new computer
system in a large suburban U.S. public school district with 100,000+
students; problems included 10,000 erroneous report cards and students
left stranded by failed class registration systems; the district's CIO was
fired. The school district decided to reinstate it's original 25-year old
system for at least a year until the bugs were worked out of the new
system by the software vendors.
- In October of 1999 the $125 million NASA Mars Climate Orbiter
spacecraft was believed to be lost in space due to a simple data
conversion error. It was determined that spacecraft software used certain
data in English units that should have been in metric units. Among other
tasks, the orbiter was to serve as a communications relay for the Mars
Polar Lander mission, which failed for unknown reasons in December 1999.
Several investigating panels were convened to determine the process failures
that allowed the error to go undetected.
- Bugs in software supporting a large commercial high-speed data
network affected 70,000 business customers over a period of 8 days in
August of 1999. Among those affected was the electronic trading system of
the largest U.S.
futures exchange, which was shut down for most of a week as a result of
the outages.
- In April of 1999 a software bug caused the failure of a $1.2
billion military satellite launch, the costliest unmanned accident in the
history of Cape Canaveral launches. The
failure was the latest in a string of launch failures, triggering a
complete military and industry review of U.S. space launch programs,
including software integration and testing processes. Congressional
oversight hearings were requested.
- A small town in Illinois
received an unusually large monthly electric bill of $7 million in March
of 1999. This was about 700 times larger than its normal bill. It turned
out to be due to bugs in new software that had been purchased by the local
power company to deal with Y2K software issues.
- In early 1999 a major computer game company recalled all copies
of a popular new product due to software problems. The company made a
public apology for releasing a product before it was ready.
- The computer system of a major online U.S. stock trading service
failed during trading hours several times over a period of days in
February of 1999 according to nationwide news reports. The problem was
reportedly due to bugs in a software upgrade intended to speed online trade
confirmations.
- In April of 1998 a major U.S.
data communications network failed for 24 hours, crippling a large part of
some U.S.
credit card transaction authorization systems as well as other large U.S.
bank, retail, and government data systems. The cause was eventually traced
to a software bug.
- January 1998 news reports told of software problems at a major U.S.
telecommunications company that resulted in no charges for long distance
calls for a month for 400,000 customers. The problem went undetected until
customers called up with questions about their bills.
- In November of 1997 the stock of a major health industry company
dropped 60% due to reports of failures in computer billing systems,
problems with a large database conversion, and inadequate software
testing. It was reported that more than $100,000,000 in receivables had to
be written off and that multi-million dollar fines were levied on the
company by government agencies.
- A retail store chain filed suit in August of 1997 against a
transaction processing system vendor (not a credit card company) due to
the software's inability to handle credit cards with year 2000 expiration
dates.
- In August of 1997 one of the leading consumer credit reporting
companies reportedly shut down their new public web site after less than
two days of operation due to software problems. The new site allowed web
site visitors instant access, for a small fee, to their personal credit
reports. However, a number of initial users ended up viewing each others'
reports instead of their own, resulting in irate customers and nationwide
publicity. The problem was attributed to "...unexpectedly high demand
from consumers and faulty software that routed the files to the wrong
computers."
- In November of 1996, newspapers reported that software bugs
caused the 411 telephone information system of one of the U.S. RBOC's to
fail for most of a day. Most of the 2000 operators had to search through
phone books instead of using their 13,000,000-listing database. The bugs
were introduced by new software modifications and the problem software had
been installed on both the production and backup systems. A spokesman for
the software vendor reportedly stated that 'It had nothing to do with the
integrity of the software. It was human error.'
- On June 4 1996 the first flight of the European Space Agency's
new Ariane 5 rocket failed shortly after launching, resulting in an
estimated uninsured loss of a half billion dollars. It was reportedly due
to the lack of exception handling of a floating-point error in a
conversion from a 64-bit integer to a 16-bit signed integer.
- Software bugs caused the bank accounts of 823 customers of a
major U.S. bank to be credited with $924,844,208.32 each in May of 1996,
according to newspaper reports. The American Bankers Association claimed
it was the largest such error in banking history. A bank spokesman said
the programming errors were corrected and all funds were recovered.
- Software bugs in a Soviet early-warning monitoring system nearly
brought on nuclear war in 1983, according to news reports in early 1999.
The software was supposed to filter out false missile detections caused by
Soviet satellites picking up sunlight reflections off cloud-tops, but
failed to do so. Disaster was averted when a Soviet commander, based on a
what he said was a '...funny feeling in my gut', decided the apparent
missile attack was a false alarm. The filtering software code was
rewritten.
Why is it often hard for management to get serious
about quality assurance?
Solving problems is a high-visibility process; preventing problems is
low-visibility. This is illustrated by an old parable:
In ancient China
there was a family of healers, one of whom was known throughout the land and
employed as a physician to a great lord. The physician was asked which of his
family was the most skillful healer. He replied,
"I tend to the sick and dying with drastic and dramatic treatments, and on
occasion someone is cured and my name gets out among the lords."
"My elder brother cures sickness when it just begins to take root, and his
skills are known among the local peasants and neighbors."
"My eldest brother is able to sense the spirit of sickness and eradicate
it before it takes form. His name is unknown outside our home."
Why does software have bugs?
- miscommunication or no communication - as to specifics of what an
application should or shouldn't do (the application's requirements).
- software complexity - the complexity of current software
applications can be difficult to comprehend for anyone without experience
in modern-day software development. Windows-type interfaces, client-server
and distributed applications, data communications, enormous relational
databases, and sheer size of applications have all contributed to the
exponential growth in software/system complexity. And the use of
object-oriented techniques can complicate instead of simplify a project
unless it is well-engineered.
- programming errors - programmers, like anyone else, can make
mistakes.
- changing requirements - the customer may not understand the
effects of changes, or may understand and request them anyway - redesign,
rescheduling of engineers, effects on other projects, work already
completed that may have to be redone or thrown out, hardware requirements
that may be affected, etc. If there are many minor changes or any major
changes, known and unknown dependencies among parts of the project are
likely to interact and cause problems, and the complexity of keeping track
of changes may result in errors. Enthusiasm of engineering staff may be
affected. In some fast-changing business environments, continuously
modified requirements may be a fact of life. In this case, management must
understand the resulting risks, and QA and test engineers must adapt and plan
for continuous extensive testing to keep the inevitable bugs from running
out of control - see 'What can be done if
requirements are changing continuously?' in Part 2 of the FAQ.
- time pressures - scheduling of software projects is difficult at
best, often requiring a lot of guesswork. When deadlines loom and the
crunch comes, mistakes will be made.
- egos - people prefer to say things like:
· 'no problem'
· 'piece of cake'
· 'I can whip that out in a few hours'
· 'it should be easy to update that old code'
·
· instead of:
· 'that adds a lot of complexity and we could end up
· making a lot of mistakes'
· 'we have no idea if we can do that; we'll wing it'
· 'I can't estimate how long it will take, until I
· take a close look at it'
· 'we can't figure out what that old spaghetti code
· did in the first place'
·
· If there are too many unrealistic 'no problem's', the
· result is bugs.
·
- poorly documented code - it's tough to maintain and modify code
that is badly written or poorly documented; the result is bugs. In many
organizations management provides no incentive for programmers to document
their code or write clear, understandable code. In fact, it's usually the
opposite: they get points mostly for quickly turning out code, and there's
job security if nobody else can understand it ('if it was hard to write,
it should be hard to read').
- software development tools - visual tools, class libraries,
compilers, scripting tools, etc. often introduce their own bugs or are
poorly documented, resulting in added bugs.
How can new Software QA processes be introduced in
an existing organization?
- A lot depends on the size of the organization and the risks
involved. For large organizations with high-risk (in terms of lives or
property) projects, serious management buy-in is required and a formalized
QA process is necessary.
- Where the risk is lower, management and organizational buy-in and
QA implementation may be a slower, step-at-a-time process. QA processes
should be balanced with productivity so as to keep bureaucracy from
getting out of hand.
- For small groups or projects, a more ad-hoc process may be
appropriate, depending on the type of customers and projects. A lot will
depend on team leads or managers, feedback to developers, and ensuring
adequate communications among customers, managers, developers, and
testers.
- In all cases the most value for effort will be in requirements
management processes, with a goal of clear, complete, testable requirement
specifications or expectations.
(See the Bookstore section's 'Software QA', 'Software
Engineering', and 'Project Management' categories for useful books with more
information.)
What is verification? validation?
Verification typically involves reviews and meetings to evaluate documents,
plans, code, requirements, and specifications. This can be done with
checklists, issues lists, walkthroughs, and inspection meetings. Validation
typically involves actual testing and takes place after verifications are
completed. The term 'IV & V' refers to Independent Verification and
Validation.
What is a 'walkthrough'?
A 'walkthrough' is an informal meeting for evaluation or informational
purposes. Little or no preparation is usually required.
What's an 'inspection'?
An inspection is more formalized than a 'walkthrough', typically with 3-8
people including a moderator, reader, and a recorder to take notes. The subject
of the inspection is typically a document such as a requirements spec or a test
plan, and the purpose is to find problems and see what's missing, not to fix
anything. Attendees should prepare for this type of meeting by reading thru the
document; most problems will be found during this preparation. The result of
the inspection meeting should be a written report. Thorough preparation for
inspections is difficult, painstaking work, but is one of the most cost effective
methods of ensuring quality. Employees who are most skilled at inspections are
like the 'eldest brother' in the parable in 'Why
is it often hard for management to get serious about quality assurance?'.
Their skill may have low visibility but they are extremely valuable to any
software development organization, since bug prevention is far more cost-effective
than bug detection.
What kinds of testing should be considered?
- Black box testing - not based on any knowledge of internal design
or code. Tests are based on requirements and functionality.
- White box testing - based on knowledge of the internal logic of
an application's code. Tests are based on coverage of code statements,
branches, paths, conditions.
- unit testing - the most 'micro' scale of testing; to test
particular functions or code modules. Typically done by the programmer and
not by testers, as it requires detailed knowledge of the internal program
design and code. Not always easily done unless the application has a
well-designed architecture with tight code; may require developing test
driver modules or test harnesses.
- incremental integration testing - continuous testing of an
application as new functionality is added; requires that various aspects
of an application's functionality be independent enough to work separately
before all parts of the program are completed, or that test drivers be
developed as needed; done by programmers or by testers.
- integration testing - testing of combined parts of an application
to determine if they function together correctly. The 'parts' can be code
modules, individual applications, client and server applications on a
network, etc. This type of testing is especially relevant to client/server
and distributed systems.
- functional testing - black-box type testing geared to functional
requirements of an application; this type of testing should be done by
testers. This doesn't mean that the programmers shouldn't check that their
code works before releasing it (which of course applies to any stage of
testing.)
- system testing - black-box type testing that is based on overall
requirements specifications; covers all combined parts of a system.
- end-to-end testing - similar to system testing; the 'macro' end
of the test scale; involves testing of a complete application environment
in a situation that mimics real-world use, such as interacting with a
database, using network communications, or interacting with other
hardware, applications, or systems if appropriate.
- sanity testing - typically an initial testing effort to determine
if a new software version is performing well enough to accept it for a
major testing effort. For example, if the new software is crashing systems
every 5 minutes, bogging down systems to a crawl, or destroying databases,
the software may not be in a 'sane' enough condition to warrant further
testing in its current state.
- regression testing - re-testing after fixes or modifications of
the software or its environment. It can be difficult to determine how much
re-testing is needed, especially near the end of the development cycle.
Automated testing tools can be especially useful for this type of testing.
- acceptance testing - final testing based on specifications of the
end-user or customer, or based on use by end-users/customers over some
limited period of time.
- load testing - testing an application under heavy loads, such as
testing of a web site under a range of loads to determine at what point
the system's response time degrades or fails.
- stress testing - term often used interchangeably with 'load' and
'performance' testing. Also used to describe such tests as system
functional testing while under unusually heavy loads, heavy repetition of
certain actions or inputs, input of large numerical values, large complex
queries to a database system, etc.
- performance testing - term often used interchangeably with
'stress' and 'load' testing. Ideally 'performance' testing (and any other
'type' of testing) is defined in requirements documentation or QA or Test
Plans.
- usability testing - testing for 'user-friendliness'. Clearly this
is subjective, and will depend on the targeted end-user or customer. User
interviews, surveys, video recording of user sessions, and other
techniques can be used. Programmers and testers are usually not
appropriate as usability testers.
- install/uninstall testing - testing of full, partial, or upgrade
install/uninstall processes.
- recovery testing - testing how well a system recovers from
crashes, hardware failures, or other catastrophic problems.
- security testing - testing how well the system protects against
unauthorized internal or external access, willful damage, etc; may require
sophisticated testing techniques.
- compatability testing - testing how well software performs in a
particular hardware/software/operating system/network/etc. environment.
- exploratory testing - often taken to mean a creative, informal
software test that is not based on formal test plans or test cases;
testers may be learning the software as they test it.
- ad-hoc testing - similar to exploratory testing, but often taken
to mean that the testers have significant understanding of the software
before testing it.
- user acceptance testing - determining if software is satisfactory
to an end-user or customer.
- comparison testing - comparing software weaknesses and strengths
to competing products.
- alpha testing - testing of an application when development is
nearing completion; minor design changes may still be made as a result of
such testing. Typically done by end-users or others, not by programmers or
testers.
- beta testing - testing when development and testing are
essentially completed and final bugs and problems need to be found before
final release. Typically done by end-users or others, not by programmers
or testers.
- mutation testing - a method for determining if a set of test data
or test cases is useful, by deliberately introducing various code changes
('bugs') and retesting with the original test data/cases to determine if
the 'bugs' are detected. Proper implementation requires large
computational resources.
(See the Bookstore section's 'Software Testing' category for
useful books on Software Testing.)
What are 5 common problems in the software
development process?
- poor requirements - if requirements are unclear, incomplete, too
general, or not testable, there will be problems.
- unrealistic schedule - if too much work is crammed in too little
time, problems are inevitable.
- inadequate testing - no one will know whether or not the program
is any good until the customer complains or systems crash.
- featuritis - requests to pile on new features after development
is underway; extremely common.
- miscommunication - if developers don't know what's needed or
customer's have erroneous expectations, problems are guaranteed.
(See the Bookstore section's 'Software QA', 'Software
Engineering', and 'Project Management' categories for useful books with more
information.)
What are 5 common solutions to software development
problems?
- solid requirements - clear, complete, detailed, cohesive,
attainable, testable requirements that are agreed to by all players. Use
prototypes to help nail down requirements.
- realistic schedules - allow adequate time for planning, design,
testing, bug fixing, re-testing, changes, and documentation; personnel
should be able to complete the project without burning out.
- adequate testing - start testing early on, re-test after fixes or
changes, plan for adequate time for testing and bug-fixing.
- stick to initial requirements as much as possible - be prepared
to defend against changes and additions once development has begun, and be
prepared to explain consequences. If changes are necessary, they should be
adequately reflected in related schedule changes. If possible, use rapid
prototyping during the design phase so that customers can see what to
expect. This will provide them a higher comfort level with their
requirements decisions and minimize changes later on.
- communication - require walkthroughs and inspections when
appropriate; make extensive use of group communication tools - e-mail,
groupware, networked bug-tracking tools and change management tools,
intranet capabilities, etc.; insure that documentation is available and
up-to-date - preferably electronic, not paper; promote teamwork and
cooperation; use protoypes early on so that customers' expectations are
clarified.
(See the Bookstore section's 'Software QA', 'Software
Engineering', and 'Project Management' categories for useful books with more
information.)
What is software 'quality'?
Quality software is reasonably bug-free, delivered on time and within budget,
meets requirements and/or expectations, and is maintainable. However, quality
is obviously a subjective term. It will depend on who the 'customer' is and
their overall influence in the scheme of things. A wide-angle view of the
'customers' of a software development project might include end-users, customer
acceptance testers, customer contract officers, customer management, the
development organization's management/accountants/testers/salespeople, future
software maintenance engineers, stockholders, magazine columnists, etc. Each
type of 'customer' will have their own slant on 'quality' - the accounting
department might define quality in terms of profits while an end-user might
define quality as user-friendly and bug-free. (See the Bookstore
section's 'Software QA' category for useful books with more information.)
What is 'good code'?
'Good code' is code that works, is bug free, and is readable and maintainable.
Some organizations have coding 'standards' that all developers are supposed to
adhere to, but everyone has different ideas about what's best, or what is too
many or too few rules. There are also various theories and metrics, such as
McCabe Complexity metrics. It should be kept in mind that excessive use of
standards and rules can stifle productivity and creativity. 'Peer reviews',
'buddy checks' code analysis tools, etc. can be used to check for problems and enforce
standards.
For C and C++ coding, here are some typical ideas to consider in setting
rules/standards; these may or may not apply to a particular situation:
- minimize or eliminate use of global variables.
- use descriptive function and method names - use both upper and
lower case, avoid abbreviations, use as many characters as necessary to be
adequately descriptive (use of more than 20 characters is not out of
line); be consistent in naming conventions.
- use descriptive variable names - use both upper and lower case,
avoid abbreviations, use as many characters as necessary to be adequately
descriptive (use of more than 20 characters is not out of line); be
consistent in naming conventions.
- function and method sizes should be minimized; less than 100 lines
of code is good, less than 50 lines is preferable.
- function descriptions should be clearly spelled out in comments
preceding a function's code.
- organize code for readability.
- use whitespace generously - vertically and horizontally
- each line of code should contain 70 characters max.
- one code statement per line.
- coding style should be consistent throught a program (eg, use of
brackets, indentations, naming conventions, etc.)
- in adding comments, err on the side of too many rather than too
few comments; a common rule of thumb is that there should be at least as
many lines of comments (including header blocks) as lines of code.
- no matter how small, an application should include documentaion
of the overall program function and flow (even a few paragraphs is better
than nothing); or if possible a separate flow chart and detailed program
documentation.
- make extensive use of error handling procedures and status and
error logging.
- for C++, to minimize complexity and increase maintainability,
avoid too many levels of inheritance in class heirarchies (relative to the
size and complexity of the application). Minimize use of multiple
inheritance, and minimize use of operator overloading (note that the Java
programming language eliminates multiple inheritance and operator
overloading.)
- for C++, keep class methods small, less than 50 lines of code per
method is preferable.
- for C++, make liberal use of exception handlers
What is 'good design'?
'Design' could refer to many things, but often refers to 'functional design' or
'internal design'. Good internal design is indicated by software code whose
overall structure is clear, understandable, easily modifiable, and
maintainable; is robust with sufficient error-handling and status logging
capability; and works correctly when implemented. Good functional design is
indicated by an application whose functionality can be traced back to customer
and end-user requirements. (See further discussion of functional and internal
design in 'What's the big deal about
requirements?' in FAQ #2.) For programs that have a user interface, it's
often a good idea to assume that the end user will have little computer
knowledge and may not read a user manual or even the on-line help; some common
rules-of-thumb include:
- the program should act in a way that least surprises the user
- it should always be evident to the user what can be done next and
how to exit
- the program shouldn't let the users do something stupid without
warning them.
What is SEI? CMM? ISO? IEEE? ANSI? Will it help?
- SEI = 'Software Engineering Institute' at Carnegie-Mellon University;
initiated by the U.S. Defense Department to help improve software
development processes.
- CMM = 'Capability Maturity Model', developed by the SEI. It's a
model of 5 levels of organizational 'maturity' that determine
effectiveness in delivering quality software. It is geared to large
organizations such as large U.S. Defense Department contractors. However,
many of the QA processes involved are appropriate to any organization, and
if reasonably applied can be helpful. Organizations can receive CMM
ratings by undergoing assessments by qualified auditors.
Level 1 - characterized by chaos, periodic panics, and heroic
efforts required by individuals to successfully
complete projects. Few if any processes in place;
successes may not be repeatable.
Level 2 - software project tracking, requirements management,
realistic planning, and configuration management
processes are in place; successful practices can
be repeated.
Level 3 - standard software development and maintenance processes
are integrated throughout an organization; a Software
Engineering Process Group is is in place to oversee
software processes, and training programs are used to
ensure understanding and compliance.
Level 4 - metrics are used to track productivity, processes,
and products. Project performance is predictable,
and quality is consistently high.
Level 5 - the focus is on continouous process improvement. The
impact of new processes and technologies can be
predicted and effectively implemented when required.
Perspective on CMM ratings: During 1997-2001, 1018 organizations
were assessed. Of those, 27% were rated at Level 1, 39% at 2,
23% at 3, 6% at 4, and 5% at 5. (For ratings during the period
1992-96, 62% were at Level 1, 23% at 2, 13% at 3, 2% at 4, and
0.4% at 5.) The median size of organizations was 100 software
engineering/maintenance personnel; 32% of organizations were
U.S. federal contractors or agencies. For those rated at
Level 1, the most problematical key process area was in
Software Quality Assurance.
- ISO = 'International Organisation for Standardization' - The ISO
9001:2000 standard (which replaces the previous standard of 1994) concerns
quality systems that are assessed by outside auditors, and it applies to
many kinds of production and manufacturing organizations, not just
software. It covers documentation, design, development, production,
testing, installation, servicing, and other processes. The full set of
standards consists of: (a)Q9001-2000 - Quality Management Systems:
Requirements; (b)Q9000-2000 - Quality Management Systems: Fundamentals and
Vocabulary; (c)Q9004-2000 - Quality Management Systems: Guidelines for
Performance Improvements. To be ISO 9001 certified, a third-party auditor
assesses an organization, and certification is typically good for about 3
years, after which a complete reassessment is required. Note that ISO
certification does not necessarily indicate quality products - it
indicates only that documented processes are followed. Also see http://www.iso.ch/ for the latest
information. In the U.S.
the standards can be purchased via the ASQ web site at http://e-standards.asq.org/
- IEEE = 'Institute of Electrical and Electronics Engineers' -
among other things, creates standards such as 'IEEE Standard for Software
Test Documentation' (IEEE/ANSI Standard 829), 'IEEE Standard of Software
Unit Testing (IEEE/ANSI Standard 1008), 'IEEE Standard for Software
Quality Assurance Plans' (IEEE/ANSI Standard 730), and others.
- ANSI = 'American National Standards Institute', the primary
industrial standards body in the U.S.; publishes some
software-related standards in conjunction with the IEEE and ASQ (American
Society for Quality).
- Other software development process assessment methods besides CMM
and ISO 9000 include SPICE, Trillium, TickIT. and Bootstrap.
- See the 'Other Resources' section for
further information available on the web.
What is the 'software life cycle'?
The life cycle begins when an application is first conceived and ends when it
is no longer in use. It includes aspects such as initial concept, requirements
analysis, functional design, internal design, documentation planning, test
planning, coding, document preparation, integration, testing, maintenance,
updates, retesting, phase-out, and other aspects. (See the Bookstore section's 'Software QA', 'Software
Engineering', and 'Project Management' categories for useful books with more
information.)
Will automated testing tools make testing easier?
- Possibly. For small projects, the time needed to learn and
implement them may not be worth it. For larger projects, or on-going
long-term projects they can be valuable.
- A common type of automated tool is the 'record/playback' type.
For example, a tester could click through all combinations of menu
choices, dialog box choices, buttons, etc. in an application GUI and have
them 'recorded' and the results logged by a tool. The 'recording' is
typically in the form of text based on a scripting language that is
interpretable by the testing tool. If new buttons are added, or some
underlying code in the application is changed, etc. the application can
then be retested by just 'playing back' the 'recorded' actions, and
comparing the logging results to check effects of the changes. The problem
with such tools is that if there are continual changes to the system being
tested, the 'recordings' may have to be changed so much that it becomes
very time-consuming to continuously update the scripts. Additionally,
interpretation of results (screens, data, logs, etc.) can be a difficult
task. Note that there are record/playback tools for text-based interfaces
also, and for all types of platforms.
- Other automated tools can include:
· code analyzers - monitor code complexity, adherence to
· standards, etc.
·
· coverage analyzers - these tools check which parts of the
· code have been exercised by a test, and may
· be oriented to code statement coverage,
· condition coverage, path coverage, etc.
·
· memory analyzers - such as bounds-checkers and leak detectors.
·
· load/performance test tools - for testing client/server
· and web applications under various load
· levels.
·
· web test tools - to check that links are valid, HTML code
· usage is correct, client-side and
· server-side programs work, a web site's
· interactions are secure.
·
· other tools - for test case management, documentation
· management, bug reporting, and configuration
· management.
What makes a good test
engineer?
A good test engineer has a 'test to break' attitude, an ability to take the
point of view of the customer, a strong desire for quality, and an attention to
detail. Tact and diplomacy are useful in maintaining a cooperative relationship
with developers, and an ability to communicate with both technical (developers)
and non-technical (customers, management) people is useful. Previous software
development experience can be helpful as it provides a deeper understanding of
the software development process, gives the tester an appreciation for the
developers' point of view, and reduce the learning curve in automated test tool
programming. Judgement skills are needed to assess high-risk areas of an
application on which to focus testing efforts when time is limited.
What makes a good Software QA engineer?
The same qualities a good tester has are useful for a QA engineer.
Additionally, they must be able to understand the entire software development
process and how it can fit into the business approach and goals of the
organization. Communication skills and the ability to understand various sides
of issues are important. In organizations in the early stages of implementing
QA processes, patience and diplomacy are especially needed. An ability to find
problems as well as to see 'what's missing' is important for inspections and
reviews.
What makes a good QA or Test manager?
A good QA, test, or QA/Test(combined) manager should:
- be familiar with the software development process
- be able to maintain enthusiasm of their team and promote a
positive atmosphere, despite what is a somewhat 'negative' process (e.g.,
looking for or preventing problems)
- be able to promote teamwork to increase productivity
- be able to promote cooperation between software, test, and QA
engineers
- have the diplomatic skills needed to promote improvements in QA
processes
- have the ability to withstand pressures and say 'no' to other
managers when quality is insufficient or QA processes are not being
adhered to
- have people judgement skills for hiring and keeping skilled
personnel
- be able to communicate with technical and non-technical people,
engineers, managers, and customers.
- be able to run meetings and keep them focused
What's the role of documentation in QA?
Critical. (Note that documentation can be electronic, not necessarily paper.)
QA practices should be documented such that they are repeatable.
Specifications, designs, business rules, inspection reports, configurations,
code changes, test plans, test cases, bug reports, user manuals, etc. should
all be documented. There should ideally be a system for easily finding and
obtaining documents and determining what documentation will have a particular
piece of information. Change management for documentation should be used if
possible.
What's the big deal about 'requirements'?
One of the most reliable methods of insuring problems, or failure, in a complex
software project is to have poorly documented requirements specifications.
Requirements are the details describing an application's externally-perceived
functionality and properties. Requirements should be clear, complete,
reasonably detailed, cohesive, attainable, and testable. A non-testable
requirement would be, for example, 'user-friendly' (too subjective). A testable
requirement would be something like 'the user must enter their previously-assigned
password to access the application'. Determining and organizing requirements
details in a useful and efficient way can be a difficult effort; different
methods are available depending on the particular project. Many books are
available that describe various approaches to this task. (See the Bookstore section's 'Software Requirements Engineering'
category for books on Software Requirements.)
Care should be taken to involve ALL of a
project's significant 'customers' in the requirements process. 'Customers'
could be in-house personnel or out, and could include end-users, customer
acceptance testers, customer contract officers, customer management, future
software maintenance engineers, salespeople, etc. Anyone who could later derail
the project if their expectations aren't met should be included if possible.
Organizations vary considerably in their
handling of requirements specifications. Ideally, the requirements are spelled
out in a document with statements such as 'The product shall.....'. 'Design'
specifications should not be confused with 'requirements'; design
specifications should be traceable back to the requirements.
In some organizations requirements may end
up in high level project plans, functional specification documents, in design
documents, or in other documents at various levels of detail. No matter what
they are called, some type of documentation with detailed requirements will be
needed by testers in order to properly plan and execute tests. Without such
documentation, there will be no clear-cut way to determine if a software
application is performing correctly.
What steps are needed to develop and run software
tests?
The following are some of the steps to consider:
- Obtain requirements, functional design, and internal design
specifications and other necessary documents
- Obtain budget and schedule requirements
- Determine project-related personnel and their responsibilities,
reporting requirements, required standards and processes (such as release
processes, change processes, etc.)
- Identify application's higher-risk aspects, set priorities, and
determine scope and limitations of tests
- Determine test approaches and methods - unit, integration,
functional, system, load, usability tests, etc.
- Determine test environment requirements (hardware, software,
communications, etc.)
- Determine testware requirements (record/playback tools, coverage
analyzers, test tracking, problem/bug tracking, etc.)
- Determine test input data requirements
- Identify tasks, those responsible for tasks, and labor
requirements
- Set schedule estimates, timelines, milestones
- Determine input equivalence classes, boundary value analyses,
error classes
- Prepare test plan document and have needed reviews/approvals
- Write test cases
- Have needed reviews/inspections/approvals of test cases
- Prepare test environment and testware, obtain needed user
manuals/reference documents/configuration guides/installation guides, set
up test tracking processes, set up logging and archiving processes, set up
or obtain test input data
- Obtain and install software releases
- Perform tests
- Evaluate and report results
- Track problems/bugs and fixes
- Retest as needed
- Maintain and update test plans, test cases, test environment, and
testware through life cycle
What's a 'test plan'?
A software project test plan is a document that describes the objectives,
scope, approach, and focus of a software testing effort. The process of
preparing a test plan is a useful way to think through the efforts needed to
validate the acceptability of a software product. The completed document will
help people outside the test group understand the 'why' and 'how' of product
validation. It should be thorough enough to be useful but not so thorough that
no one outside the test group will read it. The following are some of the items
that might be included in a test plan, depending on the particular project:
- Title
- Identification of software including version/release numbers
- Revision history of document including authors, dates, approvals
- Table of Contents
- Purpose of document, intended audience
- Objective of testing effort
- Software product overview
- Relevant related document list, such as requirements, design
documents, other test plans, etc.
- Relevant standards or legal requirements
- Traceability requirements
- Relevant naming conventions and identifier conventions
- Overall software project organization and
personnel/contact-info/responsibilties
- Test organization and personnel/contact-info/responsibilities
- Assumptions and dependencies
- Project risk analysis
- Testing priorities and focus
- Scope and limitations of testing
- Test outline - a decomposition of the test approach by test type,
feature, functionality, process, system, module, etc. as applicable
- Outline of data input equivalence classes, boundary value
analysis, error classes
- Test environment - hardware, operating systems, other required
software, data configurations, interfaces to other systems
- Test environment validity analysis - differences between the test
and production systems and their impact on test validity.
- Test environment setup and configuration issues
- Software migration processes
- Software CM processes
- Test data setup requirements
- Database setup requirements
- Outline of system-logging/error-logging/other capabilities, and
tools such as screen capture software, that will be used to help describe
and report bugs
- Discussion of any specialized software or hardware tools that
will be used by testers to help track the cause or source of bugs
- Test automation - justification and overview
- Test tools to be used, including versions, patches, etc.
- Test script/test code maintenance processes and version control
- Problem tracking and resolution - tools and processes
- Project test metrics to be used
- Reporting requirements and testing deliverables
- Software entrance and exit criteria
- Initial sanity testing period and criteria
- Test suspension and restart criteria
- Personnel allocation
- Personnel pre-training needs
- Test site/location
- Outside test organizations to be utilized and their purpose,
responsibilties, deliverables, contact persons, and coordination issues
- Relevant proprietary, classified, security, and licensing issues.
- Open issues
- Appendix - glossary, acronyms, etc.
(See the Bookstore section's 'Software Testing' and 'Software
QA' categories for useful books with more information.)
What's a 'test case'?
- A test case is a document that describes an input, action, or
event and an expected response, to determine if a feature of an
application is working correctly. A test case should contain particulars
such as test case identifier, test case name, objective, test
conditions/setup, input data requirements, steps, and expected results.
- Note that the process of developing test cases can help find
problems in the requirements or design of an application, since it
requires completely thinking through the operation of the application. For
this reason, it's useful to prepare test cases early in the development
cycle if possible.
What should be done after a bug is found?
The bug needs to be communicated and assigned to developers that can fix it.
After the problem is resolved, fixes should be re-tested, and determinations
made regarding requirements for regression testing to check that fixes didn't
create problems elsewhere. If a problem-tracking system is in place, it should
encapsulate these processes. A variety of commercial
problem-tracking/management software tools are available (see the 'Tools' section for web resources with listings of such
tools). The following are items to consider in the tracking process:
- Complete information such that developers can understand the bug,
get an idea of it's severity, and reproduce it if necessary.
- Bug identifier (number, ID, etc.)
- Current bug status (e.g., 'Released for Retest', 'New', etc.)
- The application name or identifier and version
- The function, module, feature, object, screen, etc. where the bug
occurred
- Environment specifics, system, platform, relevant hardware
specifics
- Test case name/number/identifier
- One-line bug description
- Full bug description
- Description of steps needed to reproduce the bug if not covered
by a test case or if the developer doesn't have easy access to the test
case/test script/test tool
- Names and/or descriptions of file/data/messages/etc. used in test
- File excerpts/error messages/log file excerpts/screen shots/test
tool logs that would be helpful in finding the cause of the problem
- Severity estimate (a 5-level range such as 1-5 or
'critical'-to-'low' is common)
- Was the bug reproducible?
- Tester name
- Test date
- Bug reporting date
- Name of developer/group/organization the problem is assigned to
- Description of problem cause
- Description of fix
- Code section/file/module/class/method that was fixed
- Date of fix
- Application version that contains the fix
- Tester responsible for retest
- Retest date
- Retest results
- Regression testing requirements
- Tester responsible for regression tests
- Regression testing results
A reporting or tracking
process should enable notification of appropriate personnel at various stages.
For instance, testers need to know when retesting is needed, developers need to
know when bugs are found and how to get the needed information, and
reporting/summary capabilities are needed for managers.
What is 'configuration management'?
Configuration management covers the processes used to control, coordinate, and
track: code, requirements, documentation, problems, change requests, designs,
tools/compilers/libraries/patches, changes made to them, and who makes the
changes. (See the 'Tools' section for web resources
with listings of configuration management tools. Also see the Bookstore section's 'Configuration Management' category
for useful books with more information.)
What if the software is so buggy it can't really be
tested at all?
The best bet in this situation is for the testers to go through the process of
reporting whatever bugs or blocking-type problems initially show up, with the
focus being on critical bugs. Since this type of problem can severely affect
schedules, and indicates deeper problems in the software development process
(such as insufficient unit testing or insufficient integration testing, poor
design, improper build or release procedures, etc.) managers should be
notified, and provided with some documentation as evidence of the problem.
How can it be known when to stop testing?
This can be difficult to determine. Many modern software applications are so
complex, and run in such an interdependent environment, that complete testing
can never be done. Common factors in deciding when to stop are:
- Deadlines (release deadlines, testing deadlines, etc.)
- Test cases completed with certain percentage passed
- Test budget depleted
- Coverage of code/functionality/requirements reaches a specified
point
- Bug rate falls below a certain level
- Beta or alpha testing period ends
What if there isn't enough time for thorough
testing?
Use risk analysis to determine where testing should be focused.
Since it's rarely possible to test every possible aspect of an application,
every possible combination of events, every dependency, or everything that
could go wrong, risk analysis is appropriate to most software development
projects. This requires judgement skills, common sense, and experience. (If
warranted, formal methods are also available.) Considerations can include:
- Which functionality is most important to the project's intended
purpose?
- Which functionality is most visible to the user?
- Which functionality has the largest safety impact?
- Which functionality has the largest financial impact on users?
- Which aspects of the application are most important to the customer?
- Which aspects of the application can be tested early in the
development cycle?
- Which parts of the code are most complex, and thus most subject
to errors?
- Which parts of the application were developed in rush or panic
mode?
- Which aspects of similar/related previous projects caused
problems?
- Which aspects of similar/related previous projects had large
maintenance expenses?
- Which parts of the requirements and design are unclear or poorly
thought out?
- What do the developers think are the highest-risk aspects of the
application?
- What kinds of problems would cause the worst publicity?
- What kinds of problems would cause the most customer service
complaints?
- What kinds of tests could easily cover multiple functionalities?
- Which tests will have the best high-risk-coverage to
time-required ratio?
What if the project isn't big enough to justify
extensive testing?
Consider the impact of project errors, not the size of the project. However, if
extensive testing is still not justified, risk analysis is again needed and the
same considerations as described previously in 'What
if there isn't enough time for thorough testing?' apply. The tester might
then do ad hoc testing, or write up a limited test plan based on the risk
analysis.
What can be done if requirements are changing
continuously?
A common problem and a major headache.
- Work with the project's stakeholders early on to understand how
requirements might change so that alternate test plans and strategies can
be worked out in advance, if possible.
- It's helpful if the application's initial design allows for some
adaptability so that later changes do not require redoing the application
from scratch.
- If the code is well-commented and well-documented this makes
changes easier for the developers.
- Use rapid prototyping whenever possible to help customers feel
sure of their requirements and minimize changes.
- The project's initial schedule should allow for some extra time
commensurate with the possibility of changes.
- Try to move new requirements to a 'Phase 2' version of an
application, while using the original requirements for the 'Phase 1'
version.
- Negotiate to allow only easily-implemented new requirements into
the project, while moving more difficult new requirements into future
versions of the application.
- Be sure that customers and management understand the scheduling
impacts, inherent risks, and costs of significant requirements changes.
Then let management or the customers (not the developers or testers)
decide if the changes are warranted - after all, that's their job.
- Balance the effort put into setting up automated testing with the
expected effort required to re-do them to deal with changes.
- Try to design some flexibility into automated test scripts.
- Focus initial automated testing on application aspects that are
most likely to remain unchanged.
- Devote appropriate effort to risk analysis of changes to minimize
regression testing needs.
- Design some flexibility into test cases (this is not easily done;
the best bet might be to minimize the detail in the test cases, or set up
only higher-level generic-type test plans)
- Focus less on detailed test plans and test cases and more on ad
hoc testing (with an understanding of the added risk that this entails).
Also see What
is Extreme Programming and what's it got to do with testing? elsewhere in
the Softwareqatest.com FAQ.
What if the application has functionality that
wasn't in the requirements?
It may take serious effort to determine if an application has significant
unexpected or hidden functionality, and it would indicate deeper problems in
the software development process. If the functionality isn't necessary to the
purpose of the application, it should be removed, as it may have unknown
impacts or dependencies that were not taken into account by the designer or the
customer. If not removed, design information will be needed to determine added
testing needs or regression testing needs. Management should be made aware of
any significant added risks as a result of the unexpected functionality. If the
functionality only effects areas such as minor improvements in the user
interface, for example, it may not be a significant risk.
How can Software QA processes be implemented
without stifling productivity?
By implementing QA processes slowly over time, using consensus to reach
agreement on processes, and adjusting and experimenting as an organization
grows and matures, productivity will be improved instead of stifled. Problem
prevention will lessen the need for problem detection, panics and burn-out will
decrease, and there will be improved focus and less wasted effort. At the same
time, attempts should be made to keep processes simple and efficient, minimize
paperwork, promote computer-based processes and automated tracking and
reporting, minimize time required in meetings, and promote training as part of
the QA process. However, no one - especially talented technical types - likes
rules or bureacracy, and in the short run things may slow down a bit. A typical
scenario would be that more days of planning and development will be needed,
but less time will be required for late-night bug-fixing and calming of irate
customers.
(See the Bookstore section's 'Software QA',
'Software Engineering', and 'Project Management' categories for useful books
with more information.)
What if an organization is growing so fast that
fixed QA processes are impossible?
This is a common problem in the software industry, especially in new technology
areas. There is no easy solution in this situation, other than:
- Hire good people
- Management should 'ruthlessly prioritize' quality issues and
maintain focus on the customer
- Everyone in the organization should be clear on what 'quality'
means to the customer
How does a client/server environment affect
testing?
Client/server applications can be quite complex due to the multiple dependencies
among clients, data communications, hardware, and servers. Thus testing
requirements can be extensive. When time is limited (as it usually is) the
focus should be on integration and system testing. Additionally,
load/stress/performance testing may be useful in determining client/server
application limitations and capabilities. There are commercial tools to assist
with such testing. (See the 'Tools' section for web
resources with listings that include these kinds of test tools.)
How can World Wide Web sites be tested?
Web sites are essentially client/server applications - with web servers and
'browser' clients. Consideration should be given to the interactions between
html pages, TCP/IP communications, Internet connections, firewalls,
applications that run in web pages (such as applets, javascript, plug-in
applications), and applications that run on the server side (such as cgi
scripts, database interfaces, logging applications, dynamic page generators,
asp, etc.). Additionally, there are a wide variety of servers and browsers,
various versions of each, small but sometimes significant differences between
them, variations in connection speeds, rapidly changing technologies, and
multiple standards and protocols. The end result is that testing for web sites
can become a major ongoing effort. Other considerations might include:
- What are the expected loads on the server (e.g., number of hits
per unit time?), and what kind of performance is required under such loads
(such as web server response time, database query response times). What
kinds of tools will be needed for performance testing (such as web load
testing tools, other tools already in house that can be adapted, web robot
downloading tools, etc.)?
- Who is the target audience? What kind of browsers will they be
using? What kind of connection speeds will they by using? Are they intra-
organization (thus with likely high connection speeds and similar
browsers) or Internet-wide (thus with a wide variety of connection speeds
and browser types)?
- What kind of performance is expected on the client side (e.g.,
how fast should pages appear, how fast should animations, applets, etc.
load and run)?
- Will down time for server and content maintenance/upgrades be
allowed? how much?
- What kinds of security (firewalls, encryptions, passwords, etc.)
will be required and what is it expected to do? How can it be tested?
- How reliable are the site's Internet connections required to be?
And how does that affect backup system or redundant connection
requirements and testing?
- What processes will be required to manage updates to the web
site's content, and what are the requirements for maintaining, tracking,
and controlling page content, graphics, links, etc.?
- Which HTML specification will be adhered to? How strictly? What
variations will be allowed for targeted browsers?
- Will there be any standards or requirements for page appearance
and/or graphics throughout a site or parts of a site??
- How will internal and external links be validated and updated?
how often?
- Can testing be done on the production system, or will a separate
test system be required? How are browser caching, variations in browser
option settings, dial-up connection variabilities, and real-world internet
'traffic congestion' problems to be accounted for in testing?
- How extensive or customized are the server logging and reporting
requirements; are they considered an integral part of the system and do
they require testing?
- How are cgi programs, applets, javascripts, ActiveX components,
etc. to be maintained, tracked, controlled, and tested?
Some sources of site
security information include the Usenet newsgroup 'comp.security.announce' and
links concerning web site security in the
'Other Resources' section.
Some usability guidelines to consider -
these are subjective and may or may not apply to a given situation (Note: more
information on usability testing issues can be found in articles about web site usability in the
'Other Resources' section):
- Pages should be 3-5 screens max unless content is tightly focused
on a single topic. If larger, provide internal links within the page.
- The page layouts and design elements should be consistent
throughout a site, so that it's clear to the user that they're still
within a site.
- Pages should be as browser-independent as possible, or pages
should be provided or generated based on the browser-type.
- All pages should have links external to the page; there should be
no dead-end pages.
- The page owner, revision date, and a link to a contact person or
organization should be included on each page.
Many new web site test
tools are appearing and more than 230 of them are listed in the 'Web Test Tools' section.
How is testing affected by object-oriented designs?
Well-engineered object-oriented design can make it easier to trace from code to
internal design to functional design to requirements. While there will be
little affect on black box testing (where an understanding of the internal
design of the application is unnecessary), white-box testing can be oriented to
the application's objects. If the application was well-designed this can
simplify test design.
What is Extreme Programming and what's it got to do
with testing?
Extreme Programming (XP) is a software development approach for small teams on
risk-prone projects with unstable requirements. It was created by Kent Beck who
described the approach in his book 'Extreme Programming Explained' (See the Softwareqatest.com Books page.). Testing
('extreme testing') is a core aspect of Extreme Programming. Programmers are
expected to write unit and functional test code first - before the application
is developed. Test code is under source control along with the rest of the
code. Customers are expected to be an integral part of the project team and to
help develope scenarios for acceptance/black box testing. Acceptance tests are
preferably automated, and are modified and rerun for each of the frequent
development iterations. QA and test personnel are also required to be an
integral part of the project team. Detailed requirements documentation is not
used, and frequent re-scheduling, re-estimating, and re-prioritizing is
expected. For more info see the XP-related listings in the Softwareqatest.com 'Other Resources' section.
nice.. thanks