A Survey of Software Testing Tools for Computational Science
A Survey of Software Testing Tools for
L.S. Chin, D.J. Worth, and C. Greenough
June 29, 2007
This report presents a summary of information gathered in considering software testing prac-
tices for Computational Science and Engineering. It includes an overview of software testing,
and provides a survey of tools currently available to assist in implementing testing solutions
for scientiﬁc applications written in Fortran.
Keywords: software testing, software quality, veriﬁcation, validation, Fortran
Email: L.S.Chin@rl.ac.uk, D.J.Worth@rl.ac.uk, or C.Greenough@rl.ac.uk
Reports can be obtained from www.softeng.cse.clrc.ac.uk
Software Engineering Group
Computational Science & Engineering Department
Rutherford Appleton Laboratory
Harwell Science and Innovation Campus
Oxfordshire OX11 0QX
c Science and Technology Facilites Council
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Software has a long history of being used by the scientiﬁc community as a vehicle for performing world
class research. These software are usually written by a variety of developers, and often evolve over
time to incorporate new algorithms, models or features, or are refactored to take advantage of diﬀerent
programming paradigms and cutting-edge technology.
Test suites that accompany these software play a crucial role in checking that the software functions
correctly and produces the expected results. A good set of tests serves as a safety net for developers,
ensuring that the software remains valid and internally consistent as changes are made. Additionally,
these tests allow for independent veriﬁcation by the end users thus building conﬁdence in the software.
Since most scientiﬁc software (and their test suites) are developed by domain experts rather then
Software Engineers, there is a tendency for emphasis to be on the represented model or calculation. Tests
are therefore designed around checking for acceptable results rather than discovering when or how the
software might fail.
Subsequently, this may lead to a situation where inadequate sets of tests lull developers into a false
state of conﬁdences. A 100% passing rate for a test suite that exercises only 30% of the program code
could easily mislead developers and end-users. Similarly, tests that produce correct results for a small
subset of input may lead to incorrect assumptions that the results will remain valid for all other input.
This report documents the ﬁrst steps in determining strategies for adopting high-payoﬀ software
testing practices within the scientiﬁc software development. We look at well established methodologies
practiced by the Software Engineering community, as well as software testing tools that can accelerate
the process of building, running, and managing these solutions. Due to the predominance of Fortran
among scientiﬁc software projects, it is diﬃcult for developers to take advantage of many of the available
testing tools designed mainly for the general software engineering community that has long shied away
Chapter 3, which draws heavily from the 2004 edition of the text by Myers1 , provides a broad
overview of software testing concepts and methodology used in Software Engineering.
Chapter 4 presents a survey of software tools that can potentially be used to implement testing
solutions for scientiﬁc software. This list is quite extensive, and serves as a starting point for further
This report is one of the outputs of the Software Engineering Support Programme (SESP).
1 The original book, published in 1979, is often regarded as a seminal work on software testing.
2 Software Engineering Support Programme
The Software Engineering Support Programme (SESP) (http://www.sesp.cse.clrc.ac.uk/) is an EP-
SRC support activity to provide and encourage the use of up-to-date software engineering techniques and
tools in software development within computational science and engineering.
The main goals of this SES Programme are:
• accelerate the introduction and widespread use of high-payoﬀ software engineering practices and
technology by identifying, evaluating, and maturing promising or underused technology and prac-
• maintain a long-term competency in software engineering and technology transition;
• enable the UK academic community to make measured improvements in their software engineering
practices by working with them directly;
• encourage the adoption and sustained use of standards of excellence for software engineering prac-
• foster collaborations with other groups, in the UK, Europe and the US, that have an interest in the
applications of advanced software engineering techniques in computational science.
These goals will improve the level of software engineering practice within UK computational science
research groups. As a result, the software they develop will be of a higher quality; more easily developed
and maintained; more easily re-used within the community and be computationally more eﬃcient.
The main thrust of the programme is to gather together processes and tools that will help improve
software engineering in computational science. This can be characterised by the Technology Watch,
Assessment and Evaluations process. Although the software engineering community has various very
formally deﬁned processes of software assessment and evaluation a rather more pragmatic approach has
been deﬁned for SESP.
Technology Watch – In each elements of the SESP information is gathered on a regular basis and
a rolling update made to a Technology Report that would be made available to the community
through the SESP Web site.
Assessments – The starting point of selecting a tool for use in anger is through paper assessment
using a basic requirements document. The detail of the assessment would clearly depend on the
area being addressed but a there will always be a collection of fundamental requirements such as
operating systems, supported languages etc. These paper assessments can identify tools for practical
evaluation and much of the material developed in the paper assessments added to the technology
Evaluations – Through the assessment, various tools will be selected for more direct evaluation. They
would be used in a realistic context either by SESP staﬀ or those involved in the CCP and HEC
programmes and their usefulness and eﬀectiveness documented. Although in general the evaluations
would not be placed on critical paths within the CCP or HEC activities, these programmes provide
a considerable number of representative software packages that can be made the subject of an
evaluation. The evaluations would lead to detailed reports and if successful the deployment of the
tool or practice within the main stream.
At present the two major foci for the programme are on software quality assurance and transformation
of legacy software.
3 Overview of Software Testing
Software testing involves more than just running a program to see whether it works. A single test run
reveals nothing about the program other than the obvious fact that it can yield results for a particular
set of inputs. Software testing should be treated as an investigative exercise; one which systematically
uncovers diﬀerent classes of errors within the code while demonstrating that the software behaves as
The developers’ concept of the deﬁnition and objectives of software testing plays a major role in
determining the eﬃcacy of the activity. It inﬂuences the developers’ decision on what should be tested,
and judgement on what is considered a ‘successful’ test.
For example, if the deﬁnition “Software Testing is a process of proving that a program is bug free”
were adopted, there would be a natural tendency for developers to subconsciously write fewer or less
‘destructive’ test cases with lower probabilities of breaking the program. Furthermore, the objective
that this deﬁnition implies is practically impossible to achieve. It takes only one failed test to prove the
existence of bugs, but requires an inﬁnite amount of test cases to prove otherwise. Tests can only ﬁnd
defects, not prove that there are none.
A similarly delusive deﬁnition would be “Software Testing is a process of proving that a program
performs its intended functions”. This line of thinking often leads to test cases that focuses only on
program behaviour that is inherently expected . However, programs that perform the right functions
when given a controlled set of inputs are still erroneous if they also produce unwanted side eﬀects or
fail when given unexpected inputs. A complete test should check for both expected and unexpected
behaviours, using valid as well as invalid inputs.
Myers  aptly deﬁnes software testing as “a process of executing a program with the intention of
ﬁnding errors”. Using the analogy of a medical diagnosis, a successful investigation is one that seeks
and discovers a problem, rather than one that reveals nothing and provides a false sense of well-being.
Based on this deﬁnition, we establish that a good set of test cases should be one that has a high chance
of uncovering previously unknown errors, while a successful test run is one that discovers these errors.
In order to detect all possible errors within a program, exhaustive testing is required to exercise
all possible input and logical execution paths. Except for very trivial programs, this is economically
unfeasible if not impossible. Therefore, a practical goal for software testing would be to maximise the
probability of ﬁnding errors using a ﬁnite number of test cases, performed in minimum time with minimum
Section 3.2 presents several test design strategies that can be used to work towards this goal.
3.1 Stages of Software Testing
Figure 1 presents an illustration of the diﬀerent phases of software development with a list of activities
that make up each phase. It is an extension of the V-model, and includes an additional Maintain loop
to cater for iterative software development models (e.g. evolutionary prototyping, staged delivery, etc.)
that may be more relevant to scientiﬁc application development.
The diagram is admittedly over-elaborate as it attempts to be all-encompassing; it is not meant to
describe wholly the development process of a particular software project, but instead provide a corre-
lation between diﬀerent activities that represent the building blocks of software development projects.
Developers may wish to consider only those activities relevant to their project, and from the diagram,
determine where the diﬀerent software testing stages could be applied within their software development
3.1.1 Design phase
The design phase represents a stream of activities where the software speciﬁcations are deﬁned, starting
from a high level speciﬁcation of requirements down to the detailed description of the implementation.
At each stage, an associated document is produced as well as the test criteria which reﬂect the
requirements speciﬁed in the document. If it is feasible, for instance in the case of acceptance tests based
on user requirements, the actual test cases should be written at this stage
Test criteria drawn up at the design phase would be based on an objective view of speciﬁcations,
resulting in a more complete and accurate representation of the requirements.
Figure 1: Extended V-Model which includes a Maintenance phase
3.1.2 Testing phase
The testing phase is made up of the diﬀerent stages of testing, which reﬂects a bottom-up correspondence
with the levels in which software is designed and built.
Unit Testing :
Testing a code module in isolation, ensuring that it works correctly as speciﬁed by the detailed
design. Good unit tests assist in future refactoring of code, since they give assurance that the
modiﬁed code still works as expected and can therefore be included into the project.
Integration Testing :
Testing of communication and interaction between diﬀerent code modules that are to be integrated.
Integration tests are deﬁned based on the architectural design of the system, and provide conﬁdence
that all modules can work together to achieve the functionalities speciﬁed in the design.
Code Coverage Analysis :
Determining the level of coverage for previous tests. If the level does not meet a predeﬁned threshold,
the test cases should be extended until a satisfactory coverage level is attained. Since the coverage
of test cases depends on the actual code implementation, coverage has to be re-evaluated whenever
code changes to ensure that coverage level is maintained. Test coverage will be discussed further in
System Testing :
Testing of system level requirements as stipulated by the software requirements speciﬁcation. This
might include tests for performance, interoperability, portability, usability, installability, etc.
Acceptance Testing :
Testing of the ﬁnal product against user requirements speciﬁcation. ‘User ’ may refer to actual
end-users using the program, or in the case of prototypes or novel applications, the developers that
deﬁne what they are attempting to achieve.
There is a ﬂow leading down from each test level back to the implementation phase. This represents
the fact that failed tests are followed by an implementation of a ﬁx, and a re-execution of all tests. This
form of regression testing attempts to detect any new bugs that might have been introduced when the
code was modiﬁed.
While it does seem like a lot of work, there are tools that aid in managing and automating tests. Test
management and build management tools not only make it easier to run tests, they also provide other
useful functionalities such as e-mail notiﬁcations, report generation, and defect tracking. A list of these
tools are provided in section 4.5 and 4.6.
3.1.3 Maintenance phase
The maintenance phase begins the moment the software is released. As feedback and bug reports are
received, updates to the code are planned, and the required changes reﬂected in the documentation and
test cases. The process then ﬂows back into the Implementation phase followed by the Testing phase
before the new version of the code is released.
3.1.4 Implementation phase
The implementation phase acts the link between all other phases, and represents all activities involved in
translating ideas and design into a working program. Activities that make up this phase are not limited
to the writing of programming code, but must also include other supporting components:
Unit Tests :
Any implementation or modiﬁcation of code should be follow by a relevant unit test. This ensures
that any bugs that might be present are detected early, and can be easily traced and ﬁxed.
Change Control :
It is not unusual to require changes to the design during the implementation stage. This might be
due to a change in requirements, or an oversight during the design phase. These changes should be
reﬂected in the design documents as well as the associated tests.
Quality Assurance :
All written code should be put through some form of Quality Assurance (QA) process. This might
include code conformance checking, static code analysis, build tests, memory leak detection, or even
The execution of tests and QA tools can be automated using build management tools listed in section
4.6. Using build tools, a list of predeﬁned actions can be executed whenever changes to the code are
detected, and notiﬁcation sent out whenever a problem is found.
3.2 Test Design
This section brieﬂy discusses two classes of strategies commonly used when designing software test cases.
These strategies provide a systematic approach towards creating test cases with higher chances of
discovering errors in a program and are oriented around achieving suﬃcient test coverage – the black-box
approach is designed to attain good input-output data coverage, while the white-box approach focuses
instead on program logic coverage.
3.2.1 The Black Box approach
The Black Box method, sometimes referred to as Data-Driven or Functional testing, involves taking an
external perspective of the program units and ignoring the internal workings. Test cases are deﬁned by
setting up a range of diﬀerent inputs, and comparing the results of each run against a predeﬁned list
of expected output. It is important that the expected output are predeﬁned beforehand so as to avoid
erroneous (but seemingly plausible) results from being interpreted at ﬁrst glance as being acceptable.
Initial test cases are often derived from the software speciﬁcation, with each of the speciﬁed require-
ments translated to a set of expected input-output. While this method is useful in exposing unimple-
mented parts of the speciﬁcation, it do not yet provide suﬃcient coverage of input data.
To weed out all errors, test cases would have to include combinations of not just expected and valid
inputs but all possible input. For example, in the case of a program reading from ﬁle a value represent-
ing ‘age’, a valid input may be a range of positive integers, but possible inputs would also include 0,
0.12XY ZA123, 0.2e12, −12637213232, empty strings, character strings, binary data, etc.
For most programs, this form of exhaustive input testing is not possible as it would involve an almost
inﬁnite number of test cases. Instead, a compromise is made by choosing a subset of test cases that has
the highest probability of detecting the most errors.
The following are several methodologies used to select an eﬀective subset of test cases (Examples and
detailed discussion on these methodologies are available in ).
Equivalence Partitioning :
The input domain is partitioned into a ﬁnite number of equivalence classes such that reasonable
assumptions can be made that a test of a representative value of each class is equivalent to that
of any other value in its class. Test cases can then be derived by gathering one value from each
Boundary-value analysis :
This method complements equivalence partitioning by concentrating on elements at the borders of
Cause-eﬀect graphing :
Test cases are converted from rules in a decision table. This decision table is generated from a cause-
eﬀect graph which is a logical representation of the functionality that the program is attempting to
Error guessing :
Test cases are written based on a list of error-prone conditions. Generation of the list relies on an
understanding of the program implementation as well as the science represented by the program,
and thus depends largely on the knowledge, creativity and experience of the developer.
3.2.2 The White Box approach
The White Box approach, also known as Logic-Driven or Structural testing, uses an internal perspective
of the program units where test cases are designed from an examination of the program logic. In its
simplest form, the White Box method can be seen as an iterative design strategy driven by code coverage
Using the White Box method, a testing solution can be designed along the lines of:
1. Decide on a reasonable coverage target.
2. Analyse coverage of current test cases. Initial test cases would ideally have been derived using the
Black Box approach.
3. If total coverage is below the predetermined target, study low coverage segments of the code
4. Identify and include test cases that can increase coverage
5. Re-execute tests, and repeat steps 2-4 until target coverage is achieved
A high coverage level of a test run would indicate that most of the logical paths within the program
have been traversed, which leads to a higher chance of exposing errors within the program. Coverage
level can therefore be used, to a certain extent, as a measure of the quality of the test cases.
The following is a non-exhaustive list of diﬀerent measures of coverage, each of which is increasingly
more complete but harder to achieve. (Examples and detailed discussion on these methodologies are
available in ).
Statement Coverage :
Ensuring that every statement is executed at least once.
Decision Coverage :
Ensuring that every branch direction is traversed, and (for subroutines with multiple entry points)
that every entry point is invoked at least once.
2 Code coverage is a metric which describes the degree to which a program has been exercised, and can be determined
using dynamic analysis tools. Some of these tools are presented in section 4.4
Condition Coverage :
Ensuring that each condition in a branch takes on all possible outcomes at least once, and that
every entry point is invoked at least once.
Decision-condition Coverage :
Ensuring that both decision coverage and condition coverage conditions are satisﬁed.
Multiple-condition Coverage :
Ensuring that all possible combinations of condition outcomes in each decision are invoked at least
White Box testing is very useful in ensuring that the test cases cover suﬃcient ground. It increases
the probability of exposing errors, and prevents the problem of ‘pseudo success’ – a situation where
developers are misled by a 100% passing rate when only a small portion of the program is tested.
Since developers would have to analyse and understand implementation code in order to derive test
cases, the White Box method comes with an added bonus of encouraging code inspection. Many errors
and issues (such as unnecessary or over-complicated code) could be identiﬁed during this stage even
before the tests are actually run.
As useful as it might be, White Box testing does have some limitations. It cannot show that the
program being tested meets its speciﬁcations; neither can it identify missing paths or data-dependent
problems. Therefore, it should be noted this method would not by itself produce a complete solution,
but should be used in conjunction with Black Box testing.
3.3 Deciding on a strategy
The methodologies discussed above are generic, and can be applied to any of the testing stages deﬁned
in section 3.1.2. It is up to the developer to determine an overall strategy based on a combination of
methodologies tailored to suit speciﬁc circumstances. A good strategy would be one that can strike a
balance between the thoroughness of the tests and the resources invested in developing and executing the
An example of a test design strategy that might be drawn up by a developer would be:
1. Generate test cases based on all speciﬁcation documents relevant to the code being tested. If the
speciﬁcation is in the form of input-output conditions, start with the cause-eﬀect graphing technique.
2. Supplement that with boundary-value analysis and equivalence partitioning. Ensure that both valid
and invalid conditions are covered.
3. Generate additional test cases based on error-guessing.
4. Add further test cases (based on analysing the code) until an 90% statement coverage is achieved3 .
3 An 85 − 95% statement coverage is usually a good initial target. However, one would ideally aim for full statement
coverage and a suﬃcient level of coverage for Decision and/or Condition
4 Available Tools
This chapter presents a survey of software testing tools currently available for software written in Fortran.
We have broken down the list into several categories:
• Testing Framework
• Capture and Playback
• Output Validation
• Test Coverage
• Test Management and Automation
• Build Management
The description for each tool were adapted from text available in their respective websites.
4.1 Testing Framework
Testing frameworks accelerate the testing process by providing developers with tools that assist in the
development and deployment of tests.
While each of the frameworks employ diﬀerent approaches, all of them should provide the following:
• Tools and libraries for writing test suites (a collection of test cases),
• Mechanism for setting up and tearing down a testing runtime environment,
• Standardised form or reporting and managing test results.
Available from http://sourceforge.net/projects/pfunit/
More info at http://opensource.gsfc.nasa.gov/projects/funit/pfunit.php
NASA Open Source Agreement (NOSA)
The goals of the pFUnit project are to provide a shared mechanism for supporting unit testing within the
HPC community in the hope of encouraging best practices for development and maintenance of software.
In particular, pFUnit aims to be suﬃciently minimal to encourage rapid adoption while still providing a
minimum threshold of functionality. By providing pFUnit as open source, we hope to leverage interest
from other groups to enhance portability and usability.
pFUnit is a Fortran analogue to various other xUnit testing frameworks which have been developed
within the software community, and is intended to enable test driven development (TDD) within the
scientiﬁc/technical programming community.
It was written (almost) entirely in standard conforming Fortran 95, and was developed using TDD
methodology. pFUnit is bundled with an extensive set of self-tests which are intended to evolve along
with the primary package.
pFUnit includes scripts which can conveniently wrap user-written tests into test suites and assemble
those suites into an executable. The lack of true object-orientation and reﬂection within Fortran neces-
sitates this approach. Nonetheless, once added to a developer build system adding/running additional
tests requires minimal eﬀort. The executable itself is, at least for the moment, command-line driven.
If all tests pass, then a simple summary of the number of tests run is returned. If some tests failed, a
summary of which tests failed and any associated messages is returned to standard output.
Features that will be of particular interest to the developer of scientiﬁc applications include:
• Extensive sets of assert routines for ﬂoating point, including support for single and double precision,
multidimensional arrays, and various means of expressing tolerances.
• Ability to launch MPI tests and report results back as a single test - an essential feature for high-end
computing associated with weather and climate modelling.
• Ability to repeat tests across a complex high-dimensional parameter space. The need for this
capability arises when multiple input parameters strongly interact within a subsystem. The ability
to balance performance concerns against the need to adequately sample the possibilities is very
useful. Failing parameter tests report back which combinations of parameters resulted in failures.
Available from http://funit.rubyforge.org/
NASA Open Source Agreement (NOSA)
FUnit is a unit testing framework for Fortran modules.
Unit tests are written in Fortran fragments that use a small set of testing-speciﬁc keywords and
functions. FUnit transforms these fragments into valid Fortran code and compiles, links, and runs them
against the module under test.
FUnit is opinionated software which values convention over conﬁguration. Speciﬁcally, fUnit requires
a Fortran 95 compiler, it only supports testing routines contained in modules, it requires tests to be
stored along side the code under test, and it requires that you follow a speciﬁc naming rule for test ﬁles.
The requirements for using fUnit are :
• A Fortran 90/95/2003 compiler (set via FC environment variable)
• The Ruby language with the RubyGems package manager
Available from http://www.gnu.org/software/dejagnu/
GNU General Public License (GPL)
DejaGnu is a framework for testing other programs. Its purpose is to provide a single front end for all
tests. Think of it as a custom library of Tcl procedures crafted to support writing a test harness. A Test
Harness is the testing infrastructure that is created to support a speciﬁc program or tool. Each program
can have multiple testsuites, all supported by a single test harness. DejaGnu is written in Expect, which
in turn uses Tcl (Tool command language).
DejaGnu oﬀers several advantages for testing:
• The ﬂexibility and consistency of the DejaGnu framework make it easy to write tests for any
• DejaGnu provides a layer of abstraction which allows you to write tests that are portable to any
host or target where a program must be tested. For instance, a test for GDB can run (from any
Unix based host) on any target architecture that DejaGnu supports. Currently DejaGnu runs tests
on several single board computers, whose operating software ranges from just a boot monitor to a
full-ﬂedged, Unix-like realtime OS.
• All tests have the same output format. This makes it easy to integrate testing into other software
• Using Tcl and Expect, it’s easy to create wrappers for existing testsuites. By incorporating existing
tests under DejaGnu, it’s easier to have a single set of report analyse programs..
DejaGnu is written in Expect, which in turn uses Tcl (Tool command language).
Running tests requires two things: the testing framework and the testsuites themselves. Tests are
usually written in Expect using Tcl, but you can also use a Tcl script to run a testsuite that is not based
Available from http://www.codesourcery.com/qmtest/
GNU General Public License (GPL)
QMTest is a cost-eﬀective general purpose testing solution that can be used to implement a robust, easy-
to-use testing process. QMTest runs on Windows and on most UNIX-like operating systems including
QMTest’s extensible architecture allows it to handle a wide range of application domains: everything
from compilers to graphical user interfaces to web-based applications. QMTest can easily compare test
results to known-good baselines, making analysing test results far simpler. And, because QMTest runs
on virtually all operating systems, you can use it with your entire product line.
4.1.5 Cleanscape Grayboxx
Cleanscape Software International
A complete software life-cycle testing toolset developed for software written in C, Fortran, Ada, and
Assembly. Grayboxx provides a complete software testing solution that veriﬁes functional and structural
performance requirements for mission critical applications. Grayboxx automatically conducts the follow-
ing test methodologies: Blackbox Testing, Whitebox Testing, Regression Testing, Assertion Testing, and
Grayboxx speeds the development process by allowing developers and test engineers to automatically:
• Generate test cases
• Conduct coverage analysis with complexity metrics
• Conduct unit performance testing with no probe insertions
• Generate test stubs
• Generate test harnesses
• Execute tests
• Prepare modules
• Verify results
Grayboxx also allows for both full and partial regression testing, allowing the tester to run the same
test more than once or to name the test titles to run with a subset of test cases.
4.2 Capture and Playback
Capture and Playback tools provide an alternative mechanism for testing applications. Instead of having
developers write test cases using scripts or code, these tools enable test cases to be created through the
recording of input during a program execution. These input can then be played back during the test run,
and the output compared to an expected input-output value.
These tools are independent of the programming language used in the program, and are very useful
for testing interactive programs (command-line interfaces or graphical user interfaces). These tools may
be a quick solution to preparing functional or acceptance tests.
Available from : http://expect.nist.gov/
None (public domain)
Expect is a tool for automating interactive programs. It is possible to make very sophisticated Expect
scripts. For example, diﬀerent patterns can be expected simultaneously either from one or many processes,
with diﬀerent actions in each case. Traditional control structures such as if/then/ else, procedures, and
recursion are available.
Expect’s language facilities are provided by Tcl, a very traditional scripting language. Traditionally,
users write Expect scripts by studying the interaction to be automated and writing the corresponding
Expect commands to perform the interaction. Using Autoexpect, this stage could be automated.
Autoexpect, which is part of the Expect distribution, is a program which watches a user interacting
with another program and creates an Expect script that reproduces the interactions.
For testing an interactive application, the Expect script generated by AutoExpect can be modiﬁed
and repeatedly played back with diﬀerent input values.
4.2.2 TestWorks CAPBAK
Software Research, Inc. (http://www.soft.com/Products/stwindex.html)
CAPBAK is a capture/playback tool system which allows the user to record mouse movements, keyboard
activities, widget calls and veriﬁcation information into a test script language for later use. CAPBAK
supports automatic synchronisation feature that handle minor application changes and time-sensitive
Captured images and/or character patterns provide baselines against which future runs of the tests
are compared. CAPBAK/X’s automatic output synchronisation ensures reliable playback, allowing tests
to be run unsupervised as often as required.
With the Xvirtual display capability, test runs can be executed in the background, freeing the screen
for other activities. This capability can also be used to invoke a single application multiple times on the
same workstation, thus allowing for load testing in a client/server environment.
Used in conjunction with its TestWorks/Regression companion tools, EXDIFF and SMARTS, the
regression testing process can be completely automatic. The SMARTS test management system organises
CAPBAK/X’s test sessions into a hierarchical structure for execution individually or as a part of a test
suite. This process is based on the veriﬁcation criteria selected for each test. Discrepancies are reported
by SMARTS for further analysis. Extraneous discrepancies can be masked during the comparison process
via EXDIFF. Following test execution, SMARTS logs the test statistics and generates PASS/FAIL results
into various standard reports.
4.3 Output validation
Output validation tools provide a convenient mechanism to compare results from a test run to that of
a gold standard or acceptable value. They automate the tedious task of performing result validation
especially for programs with lots of output, or for multiple runs with diﬀerent values.
Tools such as ndiﬀ and numdiﬀ are particularly useful for scientiﬁc software as they can be conﬁg-
ured with acceptable error tolerances when performing comparisons of numerical data. This avoids tiny
deviations in ﬂoating point data from being unnecessarily ﬂagged as errors.
Available from: http://sourceforge.net/projects/texttest
Project website: http://texttest.carmen.se/
OSI-Approved Open Source
TextTest works via comparing plain text logged by programs with a previous ’gold standard’ version of
The focus is around testing a particular executable program with a variety of inputs. To start with,
a plain text conﬁguration ﬁle is created that tells TextTest about your program, how to run it, and how
to test it. Tests (and test suites) are then deﬁned entirely using plain text ﬁles in a directory structure.
A test is deﬁned partly by the expected ﬁles and their contents that should be produced, and partly
by the ’input’ to provide, which can consist any or all of:
• Options to be provided on the command line
• A ﬁle to be redirected to standard input
• Environment variables that should be set
• A sequence of ’use-case’ actions to be performed on a GUI
Any output at all can be compared, so long as it is plain text, or can be converted to it.
Available from: http://www.math.utah.edu/~beebe/software/ndiff/
GNU General Public License (GPL)
Suppose that you have just run the same numerical program in two diﬀerent environments, perhaps
diﬀerent compilers on the same system, or on diﬀerent CPU architectures or operating systems. You run
diﬀ on the two program output text ﬁles, but there are thousands of diﬀerences reported. Is the program
behaving acceptably, or are there real errors that you must deal with, perhaps due to architectural
assumptions in your code, or to numerical instabilities in your algorithms, or errors in compiler-generated
code, or errors or inaccuracies in run-time libraries?
ndiﬀ is a very useful tool for solving problems like that. Simply put, it assumes that you have two text
ﬁles containing numerical values, and the two ﬁles are expected to be identical, or at least numerically
similar. ndiﬀ allows you to specify absolute and/or relative error tolerances for diﬀerences between
numerical values in the two ﬁles, and then reports only the lines with values exceeding those tolerances.
It also tells you by how much they diﬀer.
Available from: http://sourceforge.net/projects/toldiff/
Toldiﬀ is a diﬀ tool that allows tolerable (insigniﬁcant) diﬀerences between two ﬁles to be suppressed
showing only the important ones. The tolerable diﬀerences are recorded running the tool with an appro-
priate command line ﬂag.
Available from: http://www.nongnu.org/numdiff/
GNU General Public License (GPL)
Numdiﬀ is a little program that can be used to compare putatively similar ﬁles line by line and ﬁeld
by ﬁeld, ignoring small numeric diﬀerences or/and diﬀerent numeric formats. Equivalently, Numdiﬀ is
a program with the capability to appropriately compare ﬁles containing numerical ﬁelds (and not only).
By default, Numdiﬀ assumes the ﬁelds are separated by white spaces (blanks, horizontal tabulations and
newlines), but the user can also specify its list of separators.
When you compare a couple of such ﬁles, what you want to obtain usually is a list of the numerical
ﬁelds in the second ﬁle which numerically diﬀer from the corresponding ﬁelds in the ﬁrst ﬁle. Well known
tools like diﬀ, cmp or wdiﬀ can not be used to this purpose: they can not recognise whether a diﬀerence
between two numerical ﬁelds is only due to the notation or is actually a diﬀerence of numerical values.
Moreover, you could also want to ignore diﬀerences in numerical values as long as they do not overcome
a certain threshold. In other words, you could desire to neglect all small numerical diﬀerences too.
4.4 Test Coverage
Code coverage of test suites can be determined using dynamic analysis tools, some of which are listed
in this section. This information is useful when determining the thoroughness of the test cases, and are
often used when designing test cases using the White Box method (see section 3.2.2).
Using code coverage tools, developers can determine:
Cold spots Parts of the code that are never used, or just not used by the test cases.
Hot spots Parts of the code that are used frequently.
New test cases To exercise a part of the code not already tested.
This kind of testing is really a test of the completeness of the test cases, i.e. do they exercise all parts
of the code but it also gives indirect testing of the code itself. If all cases had the same cold spot(s) then
maybe that code can be removed, or if there is a common hot spot then this is an area to study in detail
to ﬁnd ways of making it more eﬃcient.
Available from: http://sourceforge.net/project/showfiles.php?group_id=3382
GNU General Public License (GPL)
gcov is a test coverage program. Use it in concert with GNU CC to analyse your programs to help create
more eﬃcient, faster running code. You can use gcov as a proﬁling tool to help discover where your
optimisation eﬀorts will best aﬀect your code. You can also use gcov along with the other proﬁling tool,
gprof, to assess which parts of your code use the greatest amount of computing time.
Proﬁling tools help you analyse your code’s performance. Using a proﬁler such as gcov or gprof, you
can ﬁnd out some basic performance statistics, such as:
• how often each line of code executes
• what lines of code are actually executed
• how much computing time each section of code uses
Once you know these things about how your code works when compiled, you can look at each module to
see which modules should be optimized. gcov helps you determine where to work on optimization.
Software developers also use coverage testing in concert with testsuites, to make sure software is
actually good enough for a release. Testsuites can verify that a program works as expected; a coverage
program tests to see how much of the program is exercised by the testsuite. Developers can then determine
what kinds of test cases need to be added to the testsuites to create both better testing and a better ﬁnal
Output from gcov can be visualised using tools such as ggcov (http://ggcov.sourceforge.net/)
and lcov (http://ltp.sourceforge.net/coverage/lcov.php).
4.4.2 Polyhedron plusFort - CVRANAL
The plusFort package includes CVRANAL, a coverage analysis facility that places probes into Fortran
source code which allow users to monitor the eﬀectiveness of testing. At the end of each run, the probes
update the coverage statistics for each source ﬁle. This data may be analysed at any time using the
CVRANAL tool. CVRANAL identiﬁes untested code blocks, and execution hot-spots.
In addition, CVRANAL can annotate your source code as shown below. The annotations are com-
ments and do not aﬀect the validity of the source code.
Available from http://www.dl.ac.uk/TCSC/UKHEC/FCAT/
FACT is similar to CRVANAL in that it reports the execution count for each line of executable source
FCAT (FORTRAN Coverage Analysis Tool) is used for the Coverage Analysis of FORTRAN codes.
• ﬁnding out ”cold-spot” in Fortran codes (the part of the codes that are never executed), and ﬂags
these parts line-by-line.
• ﬁnding out ”hot-spot” in Fortran codes (the part of the codes that are most frequently executed),
and gives a line by line proﬁle.
It is designed to working mainly with F90/F95, even through it also works with ﬁxed formatted
FORTRAN, thus F77.
FCAT oﬀers some facility for the coverage analysis of parallel codes. It treats a line as being executed
if at least one processor has executed it. The counter for the line is taken as the maximum of the number
of times this line has been executed over all processors.
4.4.4 Cleanscape Grayboxx
Cleanscape Software International
A complete software life-cycle testing toolset that includes coverage analysis with complexity metrics. It
can perform the following coverage functions
• Measure test eﬀectiveness and reliability of testing by analysing application source code
• Set up test cases and measures their eﬃciency
• Consolidate results of test coverage measurements for several scenarios or during a test campaign
• Enable eﬀective visualisation of covered and uncovered source code
Software Research, Inc.
TCAT and S-TCAT, a branch-level unit-test and system test coverage analysis tool, provides branch and
call-pair coverage for F77 and Ada programs. TCAT and S-TCAT measure the number of times each
segment or function-call pair is exercised.
C1 expresses test eﬀectiveness as the percentage of every segment exercised in a program by a test
suite, relative to the number of such segments existing in the system.
S1 expresses test eﬀectiveness as the percentage of every function-call exercised in a program by a test
suite, relative to the number of such function-calls existing in the system.
TCAT and S-TCAT instrument the application by placing markers at each segment or function-call.
When test cases have been run against the instrumented code, TCAT/S-TCAT collects and stores test
coverage data in a traceﬁle. TCAT/S-TCAT then extracts this information to create coverage reports
indicating which calls remain untested or frequently tested, and which test cases duplicate coverage.
TCAT/S-TCAT also creates archive ﬁles containing cumulative test information.
The instrumentation process also generates call-trees that identify a program’s modules and represent
the caller-callee hierarchical structure (as well as subtrees of caller-callee dependencies) within a program.
Using optional user annotation and or supplied colour annotation, the call-tree shows each functions’
level of interface exercise. When a function-call coverage values are low the user can navigate directly to
the corresponding source code. The call-trees can also generate directed graphs depicting the control-ﬂow
structure for individual modules.
4.4.6 LDRA Testbed
LDRA Testbed’s Dynamic Analysis tool provides coverage analysis at the following levels:
• Statement Coverage
• Branch/Decision Coverage
• LCSAJ Coverage
• MC/DC Coverage
• Dynamic Data Flow Coverage
4.4.7 McCabe IQ
McCabe IQ provides comprehensive test / code coverage to focus, monitor, and document software testing
processes. Using industry-standard testing methods and advanced dynamic analysis techniques, McCabe
IQ accurately assesses the thoroughness of your testing and aids in gauging the time and resources needed
to ensure a well-tested application.
McCabe IQ provides multiple levels of test coverage at the unit, integration, regression test phases
including module, lines of code, branch, path, Boolean (MC/DC for DO-178B test veriﬁcation), data,
class (OO), and architectural coverages.
4.5 Test Management and Automation
As the number of test cases for each project grows, it becomes increasingly important for these tests to
be organised and automated as much as possible. Most test management and automation tools would
provide the following functionalities:
• Organisation of information such as software requirements, test plans, and test cases.
• Test results tracking.
• Automated execution of tests. Test runs can be periodic, or triggered by events such as changes to
the source tree.
• Reports and statistics generation.
Available from: http://www.rth-is-quality.com
GNU General Public License (GPL)
rth is a web-based tool designed to manage requirements, tests, test results, and defects throughout the
application life cycle. The tool provides a structured approach to software testing and increases the vis-
ibility of the testing process by creating a common repository for all test assets including requirements,
test cases, test plans, and test results. Regardless of their geographic location, rth allows testers, devel-
opers, business analysts, and managers to monitor and gauge application readiness. The tool includes
modules for requirements management, test planning, test execution, defect tracking, and reporting.
Beneﬁts of RTH include:
• Working in remote locations is no longer a problem. View the status of your project on the web
• View progress of requirements, test execution, and bug status in real-time
• All documents (requirements, tests, test plans, supporting documents) are stored under version
• Store record or ﬁle-based requirements based on your reporting needs
• Test Tool agnostic! Take advantage of test automation with three simple functions that allow you
to write automated test results to rth
• Post and report on both manual and automated test results
Available from: http://testlink.org
GNU General Public License (GPL)
TestLink is a open source web based Test Management and test Execution system. which allow quality
assurance teams to create and manage their test cases as well as organise them into test plans. These
test plans allow team members to execute test cases and track test results dynamically, generate reports,
trace software requirements, prioritise and assign.
The tool is based on PHP, MySQL, and includes several other open source tools. It also supports Bug
tracking systems as is Bugzilla or Mantis.
In short, TestLink allow users to:
• Collect and organise test cases dynamically
• Track results and metrics associated with test execution
• Track speciﬁc information about individual tests
• Capture and report details to assist in conducting a more thorough testing process
• Customise TestLink to ﬁt requirements and processes
Available from: http://www.testmanagement.com
GNU General Public License (GPL) with options for commercial upgrades.
Professional upgrades include additional modules for extended graphical reporting capabilities and
extensible scripting functionalities.
Traq Software Ltd.
QaTraq Test Case Management Tool allows you to consolidate the manual and functional software testing
process. With one functional software testing management tool we give you the control to automate your
own techniques and strategies to track your testing, from the planning stages right through to the test
completion reporting. From communicating your test plans to managing the functional coverage of your
software testing QaTraq can help you gain control of the whole manual and functional software testing
process without changing your own strategies or techniques.
Amongst other things QAtraq can provide you with:
• Improved co-ordination between testers, team leaders and managers
• A repository of your entire manual testing progress
• A knowledge base of technical testing to share amongst a test team
• A formal channel for developers and testers to suggest tests
• Accurate tracking of your functional software testing
• Instant reports based on test cases created and executed
• Statistics listing the testing which is most eﬀective
• Control of your Manual and functional software testing.
Available from http://eiffelzone.com/esd/tstudio/
Eiﬀel Forum License, version 2
AutoTest (formerly TestStudio) is a fully automatic testing tool based on Design by Contract.
Contracts are a valuable source of information regarding the intended semantics of the software. The
information that contracts (preconditions, postconditions, class invariants, loop variants and invariants,
and check instructions) provide can be used to check whether the software fulﬁls its intended purpose.
By checking that the software respects its contracts, we can ascertain its validity. Therefore, contracts
provide the basis for automation of the testing process.
AutoTest allows the user to generate, compile and run tests at the push of a button.
Available from: http://staf.sourceforge.net
Common Public License (CPL) V1.0.
The Software Testing Automation Framework (STAF) is an open source, multi-platform, multi-language
framework designed around the idea of reusable components, called services (such as process invocation,
resource management, logging, and monitoring). STAF removes the tedium of building an automation
infrastructure, thus enabling you to focus on building your automation solution. The STAF framework
provides the foundation upon which to build higher level solutions, and provides a pluggable approach
supported across a large variety of platforms and languages.
STAF can be leveraged to help solve common industry problems, such as more frequent product
cycles, less preparation time, reduced testing time, more platform choices, more programming language
choices, and increased National Language requirements. STAF can help in these areas since it is a proven
and mature technology, promotes automation and reuse, has broad platform and language support, and
provides a common infrastructure across teams.
STAX is an execution engine which can help you thoroughly automate the distribution, execution,
and results analysis of your testcases. STAX builds on top of three existing technologies, STAF, XML,
and Python, to place great automation power in the hands of testers. STAX also provides a powerful GUI
monitoring application which allows you to interact with and monitor the progress of your jobs. Some
of the main features of STAX are: support for parallel execution, user-deﬁned granularity of execution
control, support for nested testcases, the ability to control the length of execution time, the ability to
import modules at run-time, support for existing Python and Java modules and packages, and the ability
to extend both the STAX language as well as the GUI monitoring application. Using these capabilities,
you can build sophisticated scripts to automate your entire test environment, while ensuring maximum
eﬃciency and control.
Other STAF services are also provided to help you to create an end-to-end automation solution. By
using these services in your test cases and automated solutions, you can develop more robust, dynamic
test cases and test environments.
4.6 Build Management
Build management systems automate the update-compile-test cycle of a software project. Changes to
the source code would trigger a rebuild of the application and cause the tests to be executed. This allows
developers to get immediate feedback if an error occurs, and ensures that problems are detected as early
Other tasks, such as software quality assurance analysis, can be included within the list of actions to
be performed. This ensures that the updated source code is not only correct, but is also of good quality
and adheres to standards deﬁned for the project.
Available from: http://buildbot.sourceforge.net
GNU General Public License (GPL)
The BuildBot is a system to automate the compile/test cycle required by most software projects to validate
code changes. By automatically rebuilding and testing the tree each time something has changed, build
problems are pinpointed quickly, before other developers are inconvenienced by the failure. The guilty
developer can be identiﬁed and harassed without human intervention. By running the builds on a variety
of platforms, developers who do not have the facilities to test their changes everywhere before checkin
will at least know shortly afterwards whether they have broken the build or not. Warning counts, lint
checks, image size, compile time, and other build parameters can be tracked over time, are more visible,
and are therefore easier to improve.
The overall goal is to reduce tree breakage and provide a platform to run tests or code-quality checks
that are too annoying or pedantic for any human to waste their time with. Developers get immediate
(and potentially public) feedback about their changes, encouraging them to be more careful about testing
Available from: http://www.autobuild.org/
GNU General Public License (GPL)
Test-AutoBuild is a framework for performing continuous, unattended, automated software builds. The
idea of Test-AutoBuild is to automate the building of a project’s complete software stack on a pristine
system from the high level applications, through the libraries and right down to the smallest part of the
Parabuild is a software build management server that helps software teams and organisations reduce risks
of project failures by providing practically unbreakable daily builds and continuous integration builds.
Parabuild features an eﬀortless installation process and easy overall use, multi-platform remote builds,
fast Web user interface, a wide set of supported version control, and issue tracking systems.
Available from: http://cruisecontrol.sourceforge.net
CruiseControl is composed of 2 main modules:
• the build loop: core of the system, it triggers build cycles then notiﬁes various listeners (users)
using various publishing techniques. The trigger can be internal (scheduled or upon changes in a
SCM) or external. It is conﬁgured in a xml ﬁle which maps the build cycles to certain tasks, thanks
to a system of plugins. Depending on conﬁguration, it may produce build artefacts.
• the reporting allows the users to browse the results of the builds and access the artefacts
Recently acquired by IBM and incorporated into IBM’s Rational Software suite.
IBM Rational Build Forge provides complete build and release process management through an open
framework that helps development teams standardise and automate tasks and share information. Our
products can help clients accelerate software delivery, improve software quality, as well as meet audit and
Available from: http://aegis.sourceforge.net/
GNU General Public License (GPL)
Aegis is a transaction-based software conﬁguration management system. It provides a framework within
which a team of developers may work on many changes to a program independently, and Aegis co-
ordinates integrating these changes back into the master source of the program, with as little disruption
While Aegis is not a build management system, we included it within this section as it can be used
to the same eﬀect of ensuring that code passes tests (build, testing, QA) before being merged into main
5 Further reading
1. B. Kleb & B. Wood, Computational Simulations and the Scientiﬁc Method, NASA Langley Research
2. A.H. Watson & T.J. McCabe, Structured Testing: A Testing Methodology Using the Cyclomatic
Complexity Metric, National Institute of Standards and Technology, (1996).
3. G. Dodig-Crnkovic, Scientiﬁc Methods in Computer Science, Department of Computer Science,
Mlardalen University, (2002)
4. E. Dustin, Eﬀective Software Testing: 50 Speciﬁc ways to improve your testing, Addison Wesley
5. B. Beizer, Software Testing Techniques, Van Nostrand Reinhold Co., (1990).
6. M. Fewster and D. Graham, Software Test Automation: Eﬀective use of test execution tools,
7. S.M. Baxter, S.W. Day, J.S. Fetrow & S.J. Reisinger, Scientiﬁc Software Development Is Not an
Oxymoron, PLoS Comput Biol 2(9): e87, (2006).
8. D. Libes, How to Avoid Learning Expect or Automating Automating Interactive Programs, Proceed-
ings of the Tenth USENIX System Administration Conference (LISA X), (1996).
9. S. Cornett, Code Coverage Analysis, Bullseye Testing Technology. http://www.bullseye.com/
10. W.R. Bush, J.D. Pincus & D.J. Sielaﬀ, A Static Analyzer for Finding Dynamic Programming Errors,
Intrinsa Corporation, (2000).
 D.J. Worth & C. Greenough, A Survey of Software Tools for Computational Science, Technical Report
RAL-TR-2006-011, CCLRC Rutherford Appleton Laboratory (2006).
 G.J. Myers, The Art of Software Testing, 2nd Edition, John Wiley & Sons inc., (2004).