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Chapter 13 Integration Testing
13.1 Overview:
13.1.1 Definition of integration tests:
Integration testing refers to the process of assembling different modules together for testing to verify whether the interaction and collaboration between them are normal, and to check whether the overall function of the system meets the requirements. Integration testing is usually performed after unit testing and before system testing.
13.1.2 The difference between integration testing and unit testing and system testing:
Integration testing, unit testing, and system testing are three important phases in software testing, and the differences between them are as follows:
- Unit testing is to test the independent and smallest testable unit in the software, the purpose is to ensure that the function and business logic of each unit are correct.
- Integration testing is to integrate multiple units together to test whether their interaction and collaboration are normal, so as to verify whether the functions of the entire system meet the requirements.
- System testing is to test the entire software system to check whether it meets the requirements of the user and the specifications.
13.1.3 Main tasks of integration testing:
The main tasks of integration testing include the following:
- Verify that the interface and data transfer between the various modules are correct.
- Verify that the functionality and performance of the system meets specifications, user needs, and design requirements.
- Detect the existence of loopholes and defects in the system, and make repairs and optimizations.
- Ensure system stability and reliability, and meet quality requirements.
13.1.4 Levels and principles of integration testing:
Integration testing is usually divided into four levels: unit integration testing, module integration testing, subsystem integration testing and system integration testing. The principles of integration testing include the following:
- Layer-by-layer integration: starting from unit testing, gradually integrate modules at all levels to ensure that the functions of each level are correct.
- Modular testing: Decompose the entire system into several independent modules for testing to ensure that the functions of each module are correct.
- Interface test: focus on testing whether the interface and data transfer between modules are correct.
- Automated testing: Use automated testing tools to test the system to improve testing efficiency and quality.
- Completeness testing: Ensure that all functions and boundary conditions of the system are tested, and all possible problems are found and resolved as much as possible.
13.2 Integration testing strategy:
13.2.1 Non-incremental integration:
Non-incremental integration means that after all the modules are implemented, they are assembled together for testing in one go. The advantage of this method is that the test can be completed at one time, and the problem can be quickly located and solved. The disadvantage is that it is difficult to determine the specific location of the problem, requiring a lot of debugging and repair work, and the efficiency is low.
13.2.2 Incremental integration:
Incremental integration refers to starting from unit testing and gradually integrating various modules for testing. The advantage of this method is that it can detect and solve problems early and shorten the test cycle. The disadvantage is that it needs to repeat the test at each stage, which increases the workload of the test.
13.2.3 Other integration testing strategies:
In addition to non-incremental integration and incremental integration, there are other integration testing strategies such as hybrid integration, top-down integration, and bottom-up integration. Among them, hybrid integration is a method that combines incremental integration and non-incremental integration, and can be flexibly selected according to project requirements.
13.2.4 Comparison of several integration testing implementations:
Different integration testing strategies have different implementation plans, as shown in the table:
| Integration Testing Strategy | implementation plan |
|---|---|
| non-incremental | Assemble all modules at one time for overall testing |
| Incremental | Unit Test -> Module Integration Test -> Subsystem Integration Test -> System Integration Test |
| hybrid integration | Perform non-incremental integration tests between modules first, and then perform overall incremental integration tests |
| top-down integration | First integrate high-level modules, and then gradually integrate lower-level modules |
| bottom-up integration | First integrate low-level modules, and then gradually integrate high-level modules |
Different implementation plans are suitable for different project requirements and technical conditions, and need to be selected according to specific situations.
13.3 Integration test case design:
13.3.1 Design use cases for system operation:
This method is to determine the functional and performance requirements of the system according to the system specifications and user requirements, and design test cases to verify whether the system meets these requirements.
13.3.2 Design use cases for forward testing:
This method is based on the normal use scenarios of the system, and test cases are designed to verify whether the functions and performance of the system meet the requirements under normal use conditions.
13.3.3 Design use cases for reverse testing:
This method is to consider the abnormal conditions of the system, such as input errors, network failures, etc., and design test cases to verify the fault tolerance and robustness of the system under abnormal conditions.
13.3.4 Design use cases to meet special requirements:
For some special requirements, such as security, reliability, scalability, etc., design corresponding test cases to verify whether the system meets these requirements.
13.3.5 Design use cases for high coverage:
This method is based on the analysis results of code analysis or test coverage tools, design test cases to cover each branch and boundary conditions of the code, and improve test coverage.
13.3.6 Design use cases based on module interface dependencies:
This method is to design test cases according to the interface dependencies between modules to verify whether the interfaces and data transmission between modules are correct, and to avoid system errors caused by interface problems.
13.4 The process of integration testing:
13.4.1 Planning stage:
Develop integration test plans, determine test strategies and implementation plans, determine test resources and tools, write test cases and test scripts, develop test progress and reports, etc.
13.4.2 Design implementation stage:
Design and implement test cases and test scripts according to the test plan, configure the test environment and tools, and execute unit tests and module integration tests to ensure that the functions are correct.
13.4.3 Perform evaluation phase:
Execute subsystem and system integration tests, analyze and evaluate test results, record and report test defects and problems, conduct problem tracking, repair and verification, and finally confirm that the quality and stability of the system meet the requirements.
13.5 Object-Oriented Integration Testing:
13.5.1 Object interaction:
Object-oriented integration testing emphasizes the interaction and collaboration between objects, and it needs to test whether the message passing and data sharing between classes are correct, and whether the dependencies between classes meet the design requirements.
13.5.2 Steps for object-oriented integration testing:
Object-oriented integration testing mainly includes the following steps:
- Identify classes and objects to test
- Identify dependencies and interfaces between classes
- Design and implement test cases
- Execute the test and record the results
- Analyze test results and resolve issues
13.5.3 Commonly used testing techniques for object-oriented integration testing:
Object-oriented integration testing can adopt a variety of testing techniques, such as layered testing, functional division testing, Mock object testing, etc. Among them, the Mock object test is a common method, which can simulate the behavior of the test object so that the tester can perform the test more conveniently.
13.6 Summary:
Integration testing is an important link in software testing, and its purpose is to verify whether the function and performance of the system meet the requirements. According to the actual situation, you can choose different integration testing strategies and implementation schemes, and carry out test case design and test process management. Object-oriented integration testing emphasizes the interaction and collaboration between objects, and requires the use of appropriate testing techniques to ensure the reliability and effectiveness of testing.
- Integration testing is an important link after unit testing and before system testing. In a sense, integration testing is the most critical step among the three stages.
- Integration testing is best done by developers. If the task is reported to the testing department for completion, it will easily lead to repeated testing and delay the progress.
- The strategy of integration testing is mainly designed around the coverage of a single integration test case and the traversal path of the entire integration tree.
- Various strategies have their advantages and disadvantages in terms of the scale of test cases, the workload of drivers and stub modules, and defect location, and should be used flexibly according to the actual situation