Using Test Cases

As discussed in About Test Cases, a test case contains the parameter definitions required to execute or participate in a test. When you define a test, you add one or more test cases to a test session. The test session controls the test case operations and the overall test duration, and a test session can contain multiple test cases. This topic explains the different ways in which you can use test cases, how the test system stores test cases, and test case terminology. The other topics in this section cover the procedures you will use while you work with test cases.

There are two basic groups of test cases: nodal and node. A nodal test case simulates mobile nodes, generates messages from the MNs towards the SUT, and responds to messages from the SUT. A node test case simulates a network element and listens for and responds to messages sent to it from either the SUT or other nodes included in the test. A variety of test case templates, also referred to as test case types, are included with the test applications, and each template is designed for a particular network element and network type. See the Test Applications section for more information on specific test cases.

All test case templates are stored on the TAS in the Basic section of the Test Case Library. The templates themselves can only be modified by installing a different test system release. When you create a new test case, you will begin by selecting the test server that will execute the test and a test case template, and then configure the parameters to suit your test goals. The template defines the set of parameters available in a test case, and the values and options that you select define the test case. If a template is deleted from the library, all test cases based on that template will no longer be functional.

Learn more about the Test Libraries

You can use a test case in a test session in one of two ways: as a linked test case or as a local test case. A linked test case is saved in the Test Case Library and a link to the test case is added to the test session. When the test session is opened, the current test case definition is read from the library. A local test case is saved with the test session. Changes to a test case of the same name in the library have no affect on a local test case.

Wherever the test case name is displayed, a linked test case is always identified by "{Link}--" followed by the name. In the Test Session window, a test case is identified by its name, template/type, instance, and log identifier. In the example above, the test session contains six test cases. Three are linked and three are local, but all six are of the same type (created from the same template). Each addition of the same type of test case creates a new instance of the test case. In this example there are six instances (0 — 5) of the GGSN Nodal test case. The log identifier is used in the Test Logs to label messages pertaining to a specific test case, and contains a reference to the assigned test server (ts0 in the example) and a sequential test case reference (tc0 — tc6).

Linked Test Cases vs. Local Test Cases

Any test cases that can be used in many different tests without modifying the definition, such as a benchmark nodal test, a AAA server node, or an application server (Network Host) node are good candidates for linking. Using linked test cases in these situations can save time during test configuration and when making the transition to a new RFC standard or a new SUT or test system software release. When you modify and save a linked test case, all test sessions that link to the test case are updated. Local test cases must be individually modified.

NOTES:

The definition of a linked test case is read from the library when the test session is opened. If the test case definition is modified by another user while your test session is open, the changes will not be reflected in your test session until the next time you open it.
You can link to a test case that has been saved in any section of the library, but you can only modify linked test cases that reside in a section that grants you write permissions.

Local test cases are useful for developing tests. You can experiment with the different settings until you are satisfied that the test meets your goals and then save it to the library for use in other test sessions. You can also use local test cases when you want to be certain that the settings are not inadvertently modified.

Whichever method you use, you can easily convert a linked test case to a local test case or vice versa. When you save a linked test case, you can choose to sever the link and retain a local copy of the test case. You can save a local test case and either retain a local copy or link to the test case. A copy of any test case in the library can be added to a test session as a local test case, modified, and saved with the test session.

TIP: Always keep at least one "known good" test case in the library that is not linked to any test sessions in case a linked test case is mistakenly saved with an invalid configuration. You can compare the settings between the two test cases to quickly find the error.

Upgrading Test Cases

When you install a new test system release that includes updated test case templates, the TAS compares the new and old templates. If a template has changed in a way that affects the operation of the test or in a way that requires you to modify the settings, you will receive a warning message when you open a test session that contains a test case based on that template. Color coding is used to indicate which test cases have changed and the severity of the change. See Repairing a Test Case for more information on determining and addressing changes to the template.