Software Integration Testing

Definition

Software integration testing is the incremental integration testing of two or more integrated software components on a single platform to produce failures caused by interface defects.

Objectives

The typical objectives of software integration testing are to:

Cause failures involving the interactions of the integrated software components when running on a single platform.
Report these failures to the software development team so that the underlying defects can be identified and fixed.
Help the software development team to stabilize the software so that it can be successfully distributed prior to system testing.
Minimize the number of low-level defects that will prevent effective system and launch testing.

Preconditions

Software integration testing can typically begin when the following preconditions hold:

The integration team is adequately staffed and trained in software integration testing.
The integration environment is ready.
The first two software components have:
- Passed unit testing.
- Been ported to the integration environment.
- Been integrated.

Completion Criteria

Software integration testing is typically complete when the following postconditions hold:

A test suite of test cases exists for each interface between software components.
All software integration test suites successfully execute (i.e., the tests completely execute and the actual test results match the expected test results).

Tasks

Software integration testing typically involves the integration team performing the following testing tasks:

Test Planning
Test Reuse
Test Design:
- Hierarchical Incremental Testing (HIT)
- Polymorphism Testing
Test Implementation
Test Execution:
- Regression Testing
Test Reporting

Environments

Software integration testing is typically performed on the following environments using the following tools:

Integration Environment
- Test Harness

Phases

Software integration testing consists of the following tasks being performed during the following phases:

PHASE → TASK ↓	Business Strategy	Business Optimization	Initiation	Construction	Delivery	Usage	Retirement
Test Planning	Not Applicable	Not Applicable	Started	Completed	Iterated	Iterated	Not Applicable
Test Reuse	Not Applicable	Not Applicable	Started	Completed	Iterated	Iterated	Not Applicable
Test Design	Not Applicable	Not Applicable	Started	Completed	Iterated	Iterated	Not Applicable
Test Implementation	Not Applicable	Not Applicable	Started	Completed	Iterated	Iterated	Not Applicable
Test Execution	Not Applicable	Not Applicable	Started	Completed	Iterated	Iterated	Not Applicable
Test Reporting	Not Applicable	Not Applicable	Started	Completed	Iterated	Iterated	Not Applicable

Guidelines

The iterative and incremental development cycle implies that software integration testing is regularly performed in an iterative and incremental manner.
Software integration testing must be automated if adequate regression testing is to occur.
Software integration testing can elicit failures produced by defects that are difficult to detect during system or launch testing once the system has been completely integrated.