Bottom -Up Integration
Modules are integrated from the bottom to top, in this approach processing required for modules subordinate to a given level is always available and the needs for subs is eliminated.
A bottom-up integration strategy may be implemented with the following steps:
- Low-level modules are combined into clusters that perform a specific software sub function.
- A driver 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.
As integration moves upward, the need for separate test drivers lessens. In fact, if the top two levels of program structure are integrated top-down, the number of drivers can be reduced substantially and integration of clusters is greatly simplified.
Each time a new model is added as a part of integration testing, the software changes.
New data flow paths are established, new I/O may occur, and new control logic is invoked. These changes may cause problems with functions that previously worked flawlessly. In the context of an integration test, strategy regression testing is the re-execution of subset of tests that have already been conducted to ensure that changes have not propagated unintended side effects.
Regression testing is the activity that helps to ensure that changes do not introduce unintended behavior or additional errors.
How is regression test conducted?
- Regression testing may be conducted manually, by re-executing a subset of all test cases or using automated capture playback tools.
- Capture-playback tools enable the software engineer to capture test cases and results for subsequent playback and comparison.
- The regression test suite contains three different classes of test cases.
- A representative sample of tests that will exercise all software functions.
- Additional tests that focus on software functions that are likely to be affected by the change.
- Tests that focus on software components that have been changed.
- It is impractical and inefficient to re-execute every test for every program function once a change has occurred.
Selection of an integration strategy depends upon software characteristics and some time project schedule. In general, a combined approach that uses a top-down strategy for upper levels of the program structure, coupled with bottom-up strategy for subordinate levels may be best compromise.
Regression tests should follow on critical module function.
What is critical module?
A critical module has one or more of the following characteristics.
- Addresses several software requirements
- Has a high level of control
- Is a complex or error-prone
- Has a definite performance requirement.
INTEGRATION TESTING PART ONE
INTEGRATION TESTING PART TWO
INTEGRATION TESTING PART THREE
INTEGRATION TESTING PART FOUR
INTEGRATION TESTING PART FIVE
INTEGRATION TEST STANDARDS
INTEGRATION TEST STANDARDS PART TWO
QUALITY ASSURANCE PART TWO
QUALITY ASSURANCE SQA
QUALITY OF DESIGN OF TEST CASE
QUALITY MANAGEMENT IN SOFTWARE TESTING
TOOLS FOR QUALITY MANAGEMENT
STATICAL QUALITY ASSURANCE
ISO APPROACH TO QUALITY TESTING