Methodology for Integration Testing

The following describes a methodology for creating integration test cases.

Step 1: Identify Unit Interfaces

The developer of each program unit identifies and documents the unit's interfaces for the following unit operations:

* External inquiry (responding to queries from terminals for information)
* External input (managing transaction data entered for processing)
* External filing (obtaining, updating, or creating transactions on computer files)
* Internal filing (passing or receiving information from other logical processing units)
* External display (sending messages to terminals)
* External output (providing the results of processing to some output device or unit)

Step 2: Reconcile Interfaces for Completeness

The information needed for the integration test template is collected for all program units in the software being tested. Whenever one unit interfaces with another, those interfaces are reconciled. For example, if program unit A transmits data to program unit B, program unit B should indicate that it has received that input from program unit A. Interfaces not reconciled are examined before integration tests are executed.

Step 3: Create Integration Test Conditions

One or more test conditions are prepared for integrating each program unit. After the condition is created, the number of the test condition is documented in the test template.

Step 4: Evaluate the Completeness of Integration Test Conditions

The following list of questions will help guide evaluation of the completeness of integration test conditions recorded on the integration testing template. This list can also help determine whether test conditions created for the integration process are complete.

* Is an integration test developed for each of the following external inquiries?
o — Record test
o — File test
o — Search test
o — Match/merge test
o — Attributes test
o — Stress test
o — Control test
* Are all interfaces between modules validated so that the output of one is recorded as input to another?
* If file test transactions are developed, do the modules interface with all those indicated files?
* Is the processing of each unit validated before integration testing?
* Do all unit developers agree that integration test conditions are adequate to test each unit's interfaces?
* Are all software units included in integration testing?
* Are all files used by the software being tested included in integration testing?
* Are all business transactions associated with the software being tested included in integration testing?
* Are all terminal functions incorporated in the software being tested included in integration testing?

The documentation of integration tests is started in the Test Specifications section. Also in this section, the functional decomposition continues to be refined, but the system-level test cases should be completed during this phase.

Test items in the Introduction section are completed during this phase. Items in the Test Approach and Strategy, Test Execution Setup, Test Procedures, Test Tool, Personnel Requirements, and Test Schedule continue to be refined.