|
Software QA/Testing Technical FAQs
Part:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
from low-level to high level (Testing in Stages)
Except for small programs, systems should not be tested as a single unit.
Large systems are built out of sub-systems, which are built out of modules that are composed of procedures and functions. The testing process should therefore proceed in stages where testing is carried out incrementally in conjunction with system implementation.
The most widely used testing process consists of five stages
| Component testing | Unit Testing | Verification
(Process Oriented) | White Box Testing Techniques
(Tests that are derived from knowledge of the program's structure and implementation) |
| Module Testing |
| Integrated testing | Sub-system Testing |
| System Testing |
| User testing | Acceptance Testing | Validation
(Product Oriented) | Black Box Testing Techniques
(Tests are derived from the program specification) |
However, as defects are discovered at any one stage, they require program modifications to correct them and this may require other stages in the testing process to be repeated.
Errors in program components, say may come to light at a later stage of the testing process.
The process is therefore an iterative one with information being fed back from later stages to earlier parts of the process.
How to test and to get the
difference between two images which is in the same window?
Answer1:
How are you doing your comparison? If you
are doing it manually, then you should be able to see any major differences.
If you are using an automated tool, then there is usually a comparison
facility in the tool to do that.
Answer2:
Jasper Software is an open-source utility which can be compiled into
C++ and has a imgcmp function which compares JPEG files in very good
detail as long as they have the same dimentions and number of
components.
Answer3:
Rational has a comparison tool that may be used. I'm sure Mercury
has the same tool.
Answer4:
The key question is whether we need a bit-by-bit exact
comparison, which the current tools are good at, or an equivalency
comparison. What differences between these images are not differences?
Near-match comparison has been the subject of a lot of research in
printer testing, including an M.Sc. thesis at Florida Tech. It's a
tough problem.
Testing Strategies
Strategy is a general approach rather than a method of devising particular systems for component tests.
Different strategies may be adopted depending on the type of system to be tested and the development process used.
The testing strategies are
Top-Down Testing
Bottom - Up Testing
Thread Testing
Stress Testing
Back- to Back Testing
1. Top-down testing
Where testing starts with the most abstract component and works downwards.
2. Bottom-up testing
Where testing starts with the fundamental components and works upwards.
3. Thread testing
Which is used for systems with multiple processes where the processing of a transaction threads its way through these processes.
4. Stress testing
Which relies on stressing the system by going beyond its specified limits and hence testing how well the system can cope with over-load situations.
5. Back-to-back testing
Which is used when versions of a system are available. The systems are tested together and their outputs are compared.
6. Performance testing.
This is used to test the run-time performance of software.
7. Security testing.
This attempts to verify that protection mechanisms built into system will protect it from improper penetration.
8. Recovery testing.
This forces software to fail in a variety ways and verifies that recovery is properly performed.
Large systems are usually tested using a mixture of these strategies rather than any single approach. Different strategies may be needed for different parts of the system and at different stages in the testing process.
Whatever testing strategy is adopted, it is always sensible to adopt an incremental approach to sub-system and system testing. Rather than integrate all components into a system and then start testing, the system should be tested incrementally. Each increment should be tested before the next increment is added to the system. This process should continue until all modules have been incorporated into the system.
When a module is introduced at some stage in this process, tests, which were previously unsuccessful, may now, detect defects. These defects are probably due to interactions with the new module. The source of the problem is localized to some extent, thus simplifying defect location and repai
Debugging
Brute force, backtracking, cause elimination.
|
Unit Testing
|
Coding
|
Focuses on each module and whether it works properly. Makes heavy use of white box testing
|
|
Integration Testing
|
Design
|
Centered on making sure that each module works with another module.
Comprised of two kinds:
Top-down and
Bottom-up integration.
Or focuses on the design and construction of the software architecture.
Makes heavy use of Black Box testing.(Either answer is acceptable)
|
|
Validation Testing
|
Analysis
|
Ensuring conformity with requirements
|
|
Systems Testing
|
Systems Engineering
|
Making sure that the software product works with the external environment, e.g., computer system, other software products.
|
Driver and Stubs
Driver: dummy main program
Stub: dummy sub-program
This is because the modules are not yet stand-alone programs therefore drive and or stubs have to be developed to test each unit.
Part:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
| 