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Software Testing Strategies
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Presented By:
Md. Mishbah
Md. Tofazzal Hossain
Shibani Bepary
Jarin Jahan Jenee

Table of Contents
• Software Testing
• Software Testing Strategy
• Strategic Approach to Testing
• Different type of Software Testing
• Top-Down Strategies
• Stubs and Drivers for Incremental Testing
• Bottom-up
• Big Bang Testing
• Conclusion
2Software Testing Strategy

Software Testing
• Software Testing is a process of evaluating the
functionality of a software application to find any
software bugs.
• It checks whether the developed software met the
specified requirements and identifies any defect in the
software in order to produce a quality product.

What Testing Shows
errors
requirements conformance
performance
an indication of quality

Software Testing Strategy
• Incremental testing strategies:
– Bottom-up testing
– Top-down testing
• Big bang testing

Strategic Approach to Testing
• Testing begins at the component level and works
outward toward the integration of the entire computer-
based system.
• Testing and debugging are different activities.
• Debugging must be accommodated in any testing
strategy.
• Need to consider verification issues
– are we building the product right?
• Need to Consider validation issues
– are we building the right product?

Factors affecting Software Testing Strategies
• Risks- Risk management is very important during testing to
figure out the risks and the risk level.
• Objectives-Testing should satisfy the requirements and needs of
stakeholders to succeed. The objective is to look for as many
defects as possible with less up-front time and effort invested.
• Skills-It is important to consider the skills of the testers since
strategies should not only be chosen but executed as well.
• Product-Some products have specified requirements.
• Business- Business considerations and strategy are often
important.
• Regulations- At some instances, one needs to satisfy the
regulators along with the stakeholders.

Different Types of Software Testing
• Unit Testing
• Integration Testing
• System Testing
• Smoke Testing
• Interface Testing
• Regression Testing
• Beta/Acceptance Testing
Functional Testing
Given below is the list of some common types of Software Testing:

• Performance Testing
• Security Testing
• Recovery Testing
• Load Testing
• Stress Testing
• Volume Testing
• Compatibility Testing
• Install Testing
• Reliability Testing
• Usability Testing
• Compliance Testing
• Localization Testing
Non-functional Testing
Different Types of Software Testing

Incremental Testing
• incremental testing is also performed according to
two basic strategies:
– Bottom-up and
– Top-down.
• Both incremental testing strategies assume that
the software package is constructed of a hierarchy
of software modules.

Top-Down Integration Testing
• In top-down testing, the first module tested is the
main module, the highest level module in the
software structure;
• The last modules to be tested are the lowest level
modules.

Top-Down Integration Testing Cont.
Fig: Top-Down Integrated Testing – examples

Stubs and drivers for incremental testing
• Stubs and drivers are pseudo code or dummy code used in
Integration or component testing when one or more modules are
not developed but are required to test some other module.
Stubs are used in Top-down testing approach and are
known as “called programs”. Stubs help simulate the
interface between lower lever modules which are not
available or developed.
Drivers are used in Bottom-up testing approach and are
known as “calling programs”. Drivers help simulate the
interface between top level modules which are not
developed or available.

Stubs and drivers for incremental testing Cont.
Fig: Use of stubs and drivers for incremental testing – examples

Bottom-Up Integration Testing
• In bottom-up testing, the order of testing is
reversed:
• The lowest level modules are tested first, with
the main module tested last.

Bottom-Up Integration Testing Cont.
Fig: Bottom-Up Integration Testing – examples

Big Bang Testing
• Big Bang Integration Testing is an integration testing
strategy wherein all units are linked at once, resulting
in a complete system.
• When this type of testing strategy is adopted, it is
difficult to isolate any errors found, because attention
is not paid to verifying the interfaces across individual
units.

Big Bang Testing Cont.
Fig: Big Bang Testing – examples

Big Bang Testing Drawbacks
• It is hard to separate modules when the bug is detected
• Ineffective for large systems
• High risk to miss some crucial issues while testing the
whole system
• Failures occur more frequently because of the
simultaneous check of numerous modules
• A single mistake can influence the results of the whole
integration testing

Big Bang Testing Advantages
• Low level components are combined in clusters that
perform a specific software function.
• A driver (control program) is written to coordinate
test case input and output.
• The cluster is tested.
• Drivers are removed and clusters are combined
moving upward in the program structure.

21
Conclusion
• Testing is a critically important verification
method that takes up a very large portion of a
project's resources, including schedule, budget,
staffing, and facilities.
• Unlike the many constructive activities of systems
engineering, testing is relatively unique because it
is inherently destructive.
Software Testing Strategy

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