"Software Test" class Note 05

Integration test (Integration test)

I. Concept:

Integration: Refers to the combination of multiple units to form a larger unit.

Integration testing: It is assumed that each unit has passed the unit test, checking the interface between each software unit is correct.

Two. The relationship between integration testing and unit testing:

　　

Three. The difference between integration testing and system testing:

　　

Four. The level and principle of integration testing:

1. Level:

　　　For traditional software, the integration test can be divided into 3 levels according to the integration granularity, namely: integration test, Subsystem integration test, inter-subsystem integration test

For object-oriented applications, integration testing can be divided into 2 levels according to the granularity of integration: in-class integration testing, inter-class integration testing

2. Principle:

All public interfaces must be tested to.

The critical modules must be fully tested.

Integration testing should be done at a certain level.

Integration test strategy selection should consider the relationship between quality, cost and schedule (Q.C.D).

Integration testing should start early and be based on a summary design.

In the division of modules and interfaces, testers should communicate fully with developers.

The integration test can end when the completion criteria in the test plan are met.

When the interface changes, the related interfaces involved must be regression tested.

Integration testing should be based on integrated test plans and scenarios and cannot be tested at will.

　　The project manager should ensure that the test case is audited.

　　The results of the test execution should be recorded truthfully.

Five. Integration Test strategy:

1. Non-incremental Integration:

The non-incremental integration method first tests each submodule (that is, unit tests) and then integrates all the modules together for one-time integration testing.　　　　　Advantages: (1) in a favourable situation, the integration test can be completed quickly.　　　　　(2) Minimum integration test cases.　　　　　(3) relatively simple.　　(4) Multiple testers can work in parallel.　　　　　Cons: (1) complex programs are difficult to locate and modify when they encounter problems.　　　　　(2) It is difficult to run successfully at one time. (3) Many interfaces are easily missed.

2. Add-on integration:

The program is divided into small sections to construct and test, in this process it is easier to locate and correct errors.

(1) Top-down: top-down integration (Top-down integration): Starting from the main control module, moving down the program level, gradually combining the modules. You can use a combination of depth-first or breadth-first strategies.

　　　　

Steps:

① test the main control module, using a pile module instead of the submodule called by the main control module ② according to the selected strategy (depth/breadth), each time with a real module substitution of a pile module ③ for integration testing ④ to ensure that the added module does not introduce new errors, as needed to perform regression testing.　　　　　②-④ cycle. Advantages: The ability to test the key control modules in the early stages of testing can be a complete function of the software and can verify its functionality in the early stages. Enhance the confidence of developers and users disadvantage: there is no underlying return to the real data stream, and many tests that require real data support need to be postponed

(2) Bottom-up: (bottom-up integration) Bottom-up testing starts with the module at the bottom of the software structure to assemble and test. Since the module is combined from the bottom up, it is always possible to get the required lower module processing function, so the pile module is not required.

　　　　

Steps:

① the bottom module to achieve a specific sub-function of the family ② write a test driver, coordinate the input and output of the test data ③ test the sub-functional family ④ Remove the test driver, from the bottom up to move, the function of the group into a larger sub-functional family. ②-④ cycle.

Advantages:

Allows early validation of the underlying module.

Integration testing can be done with any one leaf node ready.

can be integrated in parallel to the measured module testability.

Requirements are lower than the top-down integration strategy.

Reduce the workload of the pile module.

Support for fault isolation.

Disadvantages:

　　　　The development of the drive module is large.

　　　　The high-level tests were postponed to the end, and the overall design error was found later.

Become more complex when integrated into the top layer

(3) Sandwich integration: Sandwich integration (Sandwich integration) is a hybrid incremental test strategy that combines the advantages of both top-down and bottom-up integration methods. This method of pile module and drive module development work is relatively small, but the cost is to a certain extent increased the difficulty of locating the defect.

Steps:

① a layer in the selected structure is the target layer ② uses a bottom-up integration strategy for each layer below the target layer's layer ③ using a top-down integration strategy for the upper level of the target layer ④ the integration of the target layer with its next layer of integration ⑤ the results of the ②③④ integrated system overall test advantages: The combination of top-down and bottom　　　　　The advantages of the two strategies up. Disadvantage: The target layer is not adequately tested before integration.

"Software Test" class Note 05