software testing model

V-model
features : In the V-model, the testing process is added to the second half of the development process.
Schematic explanation : Whether the development of the code tested by the unit test meets the requirements of the detailed design. Integration tests check whether previously tested components fit together well. System testing detects whether the integrated product meets the requirements of the system specification. Acceptance testing, on the other hand, tests whether the product meets the needs of the end user.
Defects : The testing process is only regarded as a stage after the requirements analysis, system design and coding, and
          the testing of the requirements analysis, the verification of the system design, and the verification of the system design are not discovered until the later acceptance test.
          [Take testing as the last activity after coding, and the errors generated in the early stage such as requirement analysis cannot be found until the later acceptance test; it cannot reflect the principle of "implementing software testing as soon as possible and continuously"] Features of the W

model : The W model consists of two It is composed of V-shaped models, which respectively represent the parallel relationship between the testing and development process.             Compared with the V-model, the W-model increases the activities of synchronous verification and confirmation in each development stage of the software. Model Explanation : The test is accompanied by the entire software development cycle, and the test object is not only the program, but also the requirements, design, etc. to be tested, that is, the test and the development are carried out simultaneously. The W model is conducive to early and comprehensive discovery of problems. For example, after the requirements analysis is completed, the testers should participate in the verification and validation of the requirements to find out the defects as early as possible. At the same time, the testing of requirements is also conducive . For the complex and changeable situation of current software development,




   The W model does not relieve the confusion faced by test management [In the W model, activities such as requirements, design, and coding are regarded as serial, and at the same time, testing and development activities also maintain a linear relationship before and after, and the previous stage is completely over Then the next stage of work can be officially started]
Advantages : The testing activities are synchronized with the software development.
　　   The test object is not only the program, but also the requirements and design.
　　   Early detection of software defects can reduce the cost of software development. X Model Features : X model proposes Separate coding and testing for individual program fragments, and then through frequent handovers and integration, they are finally synthesized into executable programs. Model Explanation : The left side of the X model describes the separate coding and testing of individual program fragments, followed by frequent handovers and integration into executable programs, which are then tested. Finished products that have passed integration testing can be packaged and submitted to users, or as part of a larger scale and scope integration. Multiple parallel curves indicate that changes can occur in each section. As can be seen from the figure, the X model also locates exploratory testing, which is a special type of testing that is not planned in advance. Defects : waste of manpower, material and financial resources for testing, and relatively high requirements for testers’ proficiency. Advantages : help Experienced testers find more software bugs outside of the test plan Features of the H model : The test activities are completely independent, forming a completely independent process, which clearly reflects the test preparation activities and test execution activities Model Explanation









: Demonstrates a test "microcycle" at some level throughout the production cycle. Other processes marked in the figure can be any development process. For example, the design process or the coding process. That is to say, as long as the test conditions are mature and the test preparation activities are completed, the test execution activities can (or need to) be carried out.
Principle : Software testing is an independent process that runs through the entire product life cycle and is carried out concurrently with other processes. .
The H model states that software testing should be prepared as early as possible and executed as soon as possible. The different test activities can be performed in a certain order, but it can also be repeated, as long as a test reaches the readiness point, the test execution activities can be carried out.
Advantages : Software testing can be carried out as early as possible, and can be carried out hierarchically according to the different objects under test.

Reference:
http://blog.csdn.net/zjj20111217/article/details/52144883
http://www.51testing.com/html/35/128935-129203.html