1-2-5 Software Integration Process

[Activities of software integration process] (i) Software integration (ii) Evaluation and review of test readiness and software integration

(i) Development of a software integration plan

An integration plan to integrate the software units and the software components into the software configuration item is to be developed. In the integration plan, test requirements, procedures, data, responsibilities, schedules, and others are to be documented. (ii) Implementation of software integration test

Software units and software components are to be integrated in accordance with the integration plan. At this time, performing testing for each created collective will ensure that each aggregation satisfies the software requirements and that the software item is integrated at the conclusion of the integration activity. The results of integration and testing are to be documented as a software integration test report. – A test environment and test data are to be prepared and implemented under test plans in accordance with a software integration test specifications document defined in software architectural design and updated in later processes. (iii) Updating user documentation

User documentation is updated as necessary, with the inclusion of corrections of operation manuals.

• • Incremental testing
  This is a test in which tested module groups are incrementally integrated with new

modules. It is a test suited to large-scale systems, and requires dummy modules for integration testing.

• • Top-down testing
  This is a test that performs integration from top-level module to lower-level

Enlarge original visual

Source visual description

The left hierarchy has M1 above M2 and M3, with S stub boxes as leaves: two below M2 and one below M3. A rightward transition arrow leads to M1 above M2 and M3, M4 and M5 below M2, and M6 below M3. Magenta source paths indicate the integration sequence; the S leaves are replaced by the actual lower modules.

• • Bottom-up testing
  This is a test in which integration is performed from bottom-level modules to higher-level modules. It requires drivers that work as higher-level modules.

Enlarge original visual

Source visual description

The left hierarchy has D driver above M2 and M3, with M4 and M5 below M2 and M6 below M3. A rightward transition arrow leads to the same lower hierarchy beneath M1. Magenta paths show lower-module integration followed by replacing D with M1.

• • Sandwich testing
  In sandwich testing, a sandwich line is determined, after which top-down testing is performed on modules above the line and bottom-up testing is conducted on modules below the line. At the end, these are integrated at the sandwich line. This allows testing in a short period of time, but both stubs and drivers are necessary for use as dummy modules.
• • Non-incremental testing (Big bang testing)
  In this test, all modules are integrated and tested all together after each unit test is completed. It is suited to small-scale systems, and does not require dummy modules for integration testing. However, it has demerits, such as disallowing implementation in parallel with development activities, and difficulty in identifying the locations (i.e., interfaces) of the causes of detected errors.

(i) Preparation for software qualification testing

A set of tests, test cases (e.g., inputs, outputs, test criteria), and test procedures are developed and documented for conducting the software qualification testing. (ii) Evaluation of software integration

The results of software integration are to be evaluated, in consideration of standards including traceability to the system requirements (i.e., software requirements), external consistency with system requirements (i.e., software requirements), internal consistency, test coverage of the requirements of the software items, appropriateness of the test methods and test standards used, conformance to expected results, feasibility of the software qualification testing, and feasibility of operation and maintenance. The software is then to be modified and documentation updated as required. (iii) Implementation of joint review of software integration A joint review is conducted, and agreement is obtained concerning software integration.