TTCN软件使用说明

1 Purpose

The purpose of this exercise is to learn how to test protocols using TTCN.

2 Conformance testing

Conformance testing is the process of verifying that an implementation performs in accordance with a particular standard/specification/environment.

Conformance testing is exclusively concerned with the external behavior of an implementation. Service and functional behavior is tested in order to find logical errors and prerequisites for interoperability. Conformance testing is not intended to be exhaustive and a successfully passed test suite does not imply a 100% guarantee. But it does ensure, with a reasonable degree of confidence, that the implementation is consistent with its specifications, and it does increase the probability that implementations will interwork.

2.1 Test architecture

2.2 Terms

Abstract Test Suite

Independent of test system, hardware and software. The ATS defines the test of the implementation under test (IUT), which is treated in a black box model,

< only its exterior interface is of concern. The IUT is stimulated byabs工程塑料

sequences of test events and its response is inspected.

System Under Test (SUT)

The whole test system including hardware, software etc. Contains the implementation under test (IUT).

Implementation Under Test (IUT)

The implementation of the protocol that is tested. Black box.

Test system

The system/device performing the tests.

Lower tester (LT)

The test components which communicate with the IUT via the PCOs at the lower interface.

Upper tester (UT)

The test components which communicate with the IUT via the PCOs at the upper interface.

Point of Control and Observation (PCO)

巴拿马型船Communication between the test components and the IUT or service provider is achieved via points of control and observation (PCOs). PCO have to be declared for each channel to/from the environment in the SDL system. Protocol Data Unit (PDU)

Packets delivered between certain protocol layers.

Abstract Service Primitive (ASP)

Packets between layers.

Master Test Component (MTC)

There must be at least one test component always present in the test system.

This is called the master test component (MTC) and it is responsible for coordinating and controlling the test and for setting the final verdict of the test. Parallel Test Component

A test component created by the main test system is referred to as a Parallel

Test Component (PTC).

Test Coordination Procedure (TCP)

陈少霞三级Coordination between the LT and the UT is achieved by test coordination procedures (TCP).

3 TTCN language

TTCN (Tree and Tabular Combined Notation, ISO/IEC 9646-3) is a language standardized by ISO for the specification of tests for real-time and communicating systems. TTCN has been developed within the framework of standardized conformance testing (ISO/ IEC 9646).

With TTCN a test suite is specified. Test suites formalize the manner for establishing conformance or interoperability. They come in two forms: abstract and executable. A test suite is a collection of various test cases together with all the declarations and components it needs. Each test case is des

cribed as an event tree. In this tree, behaviors such as "First, we send A, then either B or C is received; if it was B we will " are described. Concurrent TTCN allows several event trees to run concurrently.

TTCN is abstract in the sense of being test system independent. This means that a test suite in TTCN for one application (e.g. protocol, system, etc.) can be used in any test environment for that application.

The use of TTCN has increased tremendously during the last few years. This has been augmented by the significant amount of test suites released by various standardization bodies. TTCN is not only used in standardization work. The language is very suitable for all kinds of functional testing for real-time and communicating systems. This has led to a wide usage throughout the industry.

The specifications of the messages being sent and received can be defined using either the native form of TTCN or by using ASN.1 (Abstract Syntax Notation One).

3.1 The major parts of TTCN specification

A TTCN specification has a standardized layout that produces comprehensive and unambiguous pa

per printouts. This greatly improves clarity and readability. A test suite is divided into the following four major parts:

燕太子丹• The overview part, containing a table of contents and a description of the test suite. Its purpose is mainly to document the test suite to increase clarity and readability.

• The declarations part, declaring all messages, variables, timers, data structures and black box interface towards the Implementation Under Test.

• The constraints part, assigning values and creating constraints for inspection of responses from the implementation under test.

• The dynamic part, containing all test cases, test steps and default tables with test events and verdicts, i.e. it describes the actual execution behavior of the test suite.

3.1.1 Dynamic part

4 TTCN Suite: using TTCN link

TTCN Link automatically generates the TTCN declarations part based on an SDL specification. The 征服者1453

default dynamic behavior table is also generated. It contains timeout and otherwise statements for each PCO, which will ensure that any incorrect response from the implementation under test always will give a FAIL verdict as a result from the test case. After the default and constraints tables have been generated, you can interactively build test cases.

When you use TTCN Link, there are four phases involved:

1. In the Organizer, you generate a TTCN Link application from your SDL

system.

2. In the TTCN suite, you use TTCN Link for generating the declarations part.

3. In the TTCN suite, you interactively build test cases.

4.1 Generating a TTCN Link Executable

Once the SDL specification describing the system to be tested and the test architecture are finished, you can generate a Link executable. You do this in the same way as when you generate an SDL Simulator or Validator.

To generate a Link executable:

1. Select Make from the Generate menu in the Organizer.

2. The Make dialog will be opened.宜宾县教育网

3. Select Analyze & generate code (Cbasic).

4. Select Generate Makefile.

5. Select Use Standard Kernel and TTCN Link (Microsoft TTCN-link).

6. If necessary, change other options.

7. Click Full Make.

The Link executable will now be generated. It includes the information about the SDL specification that is needed for generation of the TTCN declarations. The name of the executable will be <sdl system name>_xxx.link, where xxx is

depending on the compiler used.

4.2 Generating the TTCN Declarations

Before the actual generation of the TTCN declarations, you have to specify the Link executable - and thereby the SDL system - to use.

1. Add new TTCN Test Suite file to your system, but don’t open the editor.

2. Select the ASN.1 file from the organizer, click the right mouse button and

select Dependencies…. Following dialog opens:

3. Select the test suite from the list and click OK.

4. Open the TTCN suite from organizer by double clicking the test suite icon

you just created.

5. Select Select SDL to TTCN Link Executable from the SDL to TTCN link menu.

The Select Link Executable dialog will be opened.

6. In the dialog, select the Link executable and click OK.