Getting started with testing - integration testing

1. The definition of integration testing

Integration testing is based on unit testing , The test of assembling all functions into a system or subsystem according to the outline design requirements ; Integration testing and unit testing are different , therefore , They contain disjoint regions on the set of problems found , There is no substitute for each other ; Integration testing , Also called battery of tests 、 The joint test 、 Subsystem test or component test

Integration testing focuses on the interfaces between units and the functions after integration . in other words , Integration testing is mainly to check the mutual calls between different module codes , And the interaction between modules and related modules .

2. The main strategy of integration testing

There are nine main strategies for integration testing , Including big bang integration 、 Top down Integration 、 Bottom up integration 、 Sandwich Integration 、 Backbone Integration 、 Layered Integration 、 Function based Integration 、 Message based Integration 、 Schedule based Integration 、 Risk based Integration

2.1 Big bang Integration

In this way of integration , First, unit test each module separately , Then put all the units together for testing , Finally, we get a software system that meets the requirements

advantage ： Big bang integration can quickly complete integration testing , And only a few drive and pile module designs . It also requires the least number of test cases , And the method is relatively simple

shortcoming ： This one-time assembly method attempts to be assisted by auxiliary modules , On the basis of module unit test , Connect the tested modules for testing . But because the program inevitably has the interface between modules 、 Global data structure and other issues , Therefore, the probability of a successful trial run is not very high ; When you find problems ,bug It is difficult to locate and repair .

2.2 Top down integration

The top-down integration method tests the system in the same order as the design , It verifies the control interface of the system in the first time ; Using top-down integration testing focuses first on top-level components , Then step by step test the underlying components .

advantage ： The top-down integration method verifies the main control and judgment points earlier in the test process ; If the depth direction assembly method is selected , You can first implement and verify a complete software function ; The functional feasibility was proved earlier , It can also give developers and users confidence in success ; Only one driver at most , Reduced drive development costs .

shortcoming ： Validation of the underlying components has been delayed ; As the number of underlying components increases , The composition of the whole system is becoming more and more complex , This leads to inadequate testing of underlying components , Especially those components that are reused .

2.3 Sandwich Integration

Sandwich integration divides the system into three layers , The middle layer is the target layer . When it comes to testing , Adopt the top-down integration strategy for the layer above the target layer , Adopt a bottom-up integration strategy for the layer below the target layer , Finally, the test meets at the target layer .

It is generally used for the integration of large projects .

2.4 Bottom up integration

The bottom-up integration method is to assemble and test from the lowest components of the program structure ; Components are assembled from the bottom up , For a given hierarchy of components , Its subcomponents have been assembled and tested , So no piles are required .