UNIFACE TEST DRIVEN DEVELOPMENT - Compuware Corporation

FACTSHEET: COMPUWARE UNIFACE
UNIFACE TEST DRIVEN DEVELOPMENT
Improve Software Quality, Reduce Overall Costs
Test Driven Development is the key
Developing quality software to tight budgets and timescales
is challenging enough already, so why make matters worse
by fixing bugs late in the lifecycle? It’s more expensive to
fix a bug in testing than during development, and more
expensive still to fix it once the software has been released.
Test Driven Development (TDD) helps developers find and
fix bugs early in the development process, and improves the
design and support process.
THE PROBLEM
With traditional approaches, when the same code is re-used in several
places, it can be hard to identify whether a change to that code is
going to cause problems, and if so where. It’s even more difficult when
the code is being maintained by someone other than the author – by
support staff, for example. It’s also easy for bugs to be re-introduced
by subsequent changes without being spotted. Regression-testing the
complete application can be prohibitively expensive.
WHAT IS TEST DRIVEN DEVELOPMENT (TDD)
AND HOW CAN IT HELP?
TDD is an approach that improves software quality and reduces the
lifecycle cost of software.
In TDD, developers write automated test scripts for low-level functions
before coding the functions. The test scripts ‘assert’ the results that
should be returned when the code is called with specified test data.
These tests are used to verify that the required functionality is correctly
implemented initially, and can then be re-used as regression tests
when subsequent changes are made, to ensure that nothing has been
broken.
TDD is typically associated with ‘agile’ software development, but
can be used with any methodology, and can be introduced in an
evolutionary manner. It is, for example, possible to write a test of this
type when changing existing code. TDD complements other types of
testing rather than replacing them.
Figure 1: The Compuware TDD process in the application life cycle

WHAT IS TEST DRIVEN DEVELOPMENT (TDD)
AND HOW CAN IT HELP? (Continued)
The TDD approach has a number of benefits:
• It results in better design, as the process of creating tests helps
the developer to decide how best to implement the code
• The tests document the code behavior, as they are an up-to-date
record of expected results when calling the code with given test
data
• Breaking changes are identified early, and are more likely to be
fixed prior to acceptance testing
• The developer thinks about failure scenarios in advance, and, by
documenting them in the form of tests, ensures that they are not
forgotten
• The underlying cause of runtime problems can be identified more
easily.
The screenshot below shows the interactive test runner with some
errors that the developer is working on. When the code is fixed, the
developer will re-run tests and should see green ticks indicating that
the code is working correctly.
Figure 1: Interactive test runner.
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REFACTORING AND TDD
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12.10
During both development and maintenance, it makes sense to re-use
existing code wherever possible. ‘Refactoring’ is the term used for the
process of re-organizing code so that it performs well when re-used.
The process also creates an elegant interface to facilitate re-use.
COMPUWARE CAN HELP YOU IMPLEMENT TDD
If you’re thinking of adopting TDD, it makes sense to talk to Compuware
Uniface. We can provide a service that includes the following:
• Test runner software, as shown above
• A framework for writing and running tests with assertions
• Experienced consultants who can share knowledge of best
practices
• Test framework documentation
• Low-cost implementation (typically only a 2-day engagement is
required).
In addition, you get to keep the source code for the test framework and
test runner, so you can customize the solution if required.
COMPLEMENTARY OFFERINGS
When our TDD approach is combined with Continuous Integration
(see separate fact sheet), all your tests can be re-run automatically
whenever someone makes a change. That gives you extra confidence
that changes aren’t breaking other parts of the system, and makes it
easy to build releases on demand.
If you’d like to know more about TDD, or about our products and
services in this area, Compuware Uniface Services can help.
E-mail: askuniface@compuware.com
Tel: +44 (0)1628 611000
To learn more, visit: www.uniface.com