SIST ES 202 786 V1.1.1:2014

SLOVENSKI STANDARD
SIST ES 202 786 V1.1.1:2014
01-julij-2014

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Methods for Testing and Specification (MTS) - The Testing and Test Control Notation

version 3 - TTCN-3 Language Extensions: Support of interfaces with continuous signals

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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Intellectual Property Rights ................................................................................................................................ 5

Foreword ............................................................................................................................................................. 5

1 Scope ........................................................................................................................................................ 6

2 References ................................................................................................................................................ 6

2.1 Normative references ......................................................................................................................................... 6

2.2 Informative references ........................................................................................................................................ 7

3 Definitions and abbreviations ................................................................................................................... 7

3.1 Definitions .......................................................................................................................................................... 7

3.2 Abbreviations ..................................................................................................................................................... 7

4 Package conformance and compatibility .................................................................................................. 7

5 Package concepts for the core language ................................................................................................... 8

5.1 Time and Sampling ............................................................................................................................................ 9

5.1.1 The now operator .......................................................................................................................................... 9

5.1.2 Define the default step size for sampling ...................................................................................................... 9

5.2 Data streams ..................................................................................................................................................... 10

5.2.1 Data Streams: static perspective ................................................................................................................. 11

5.2.2 Data Streams: dynamic perspective ............................................................................................................ 12

5.2.2.1 Defining stream port types .................................................................................................................... 12

5.2.2.2 Declaration and instantiation of stream ports ........................................................................................ 13

5.2.3 Data stream access operations .................................................................................................................... 14

5.2.3.1 The value operation ............................................................................................................................... 14

5.2.3.2 The timestamp operation ....................................................................................................................... 15

5.2.3.3 The delta operation ................................................................................................................................ 16

5.2.4 Data stream navigation operations .............................................................................................................. 16

5.2.4.1 The prev operation ................................................................................................................................ 16

5.2.4.2 The at operation .................................................................................................................................... 17

5.2.5 Data stream extraction and application operations ..................................................................................... 18

5.2.5.1 The history operation ............................................................................................................................ 18

5.2.5.2 The values operation ............................................................................................................................. 19

5.2.5.3 The apply operation............................................................................................................................... 20

5.3 The assert statement ......................................................................................................................................... 21

5.4 Control structures for continuous and hybrid behaviour .................................................................................. 22

5.4.1 Modes ......................................................................................................................................................... 22

5.4.1.1 Definition of the until block .................................................................................................................. 24

5.4.1.1.1 Definition of transition guards and events ....................................................................................... 25

5.4.1.1.2 Definition of follow up modes ......................................................................................................... 25

5.4.1.1.3 The repeat statement ........................................................................................................................ 26

5.4.1.1.4 The continue statement .................................................................................................................... 27

5.4.1.2 Definition of invariant blocks ............................................................................................................... 27

5.4.1.3 Definition of the onentry block ............................................................................................................. 28

5.4.1.4 Definition of the onexit block ............................................................................................................... 28

5.4.1.5 Local predicate symbols in the context of modes ................................................................................. 29

5.4.1.6 The duration operator ............................................................................................................................ 30

5.4.2 Atomic modes: the cont statement .............................................................................................................. 30

5.4.3 Parallel mode composition: the par statement ............................................................................................ 31

5.4.4 Sequential mode composition: the seq statement........................................................................................ 33

5.4.5 Parameterizable modes ............................................................................................................................... 34

5.4.5.1 Mode types ............................................................................................................................................ 34

5.4.5.2 Parameterizable mode definitions ......................................................................................................... 35

5.5 The wait statement............................................................................................................................................ 36

6 TRI extensions for the package .............................................................................................................. 36

6.1 triStartClock (TE → PA) .................................................................................................................................. 36

6.2 triReadClock (TE → PA) ................................................................................................................................. 36

6.3 triNextSampling (TE → PA, SA → PA) .......................................................................................................... 37

6.4 triBeginWait (TE → PA) ................................................................................................................................. 37

6.5 triProcessStep (PA → TE) ............................................................................................................................... 37

6.6 triEndWait (PA → TE) ..................................................................................................................................... 38

6.7 triSetStreamValue (TE → SA) ......................................................................................................................... 38

6.8 triGetStreamValue (TE → SA) ........................................................................................................................ 39

7 TCI extensions for the package .............................................................................................................. 39

7.1 tciSetStreamValueReq (TE → CH) .................................................................................................................. 39

7.2 tciSetStreamValue (CH → TE) ........................................................................................................................ 40

Annex A (normative): BNF and static semantics .............................................................................. 41

A.1 Changed BNF Rules ............................................................................................................................... 41

A.2 New BNF Rules ..................................................................................................................................... 42

Annex B (informative): Bibliography ................................................................................................... 44

History .............................................................................................................................................................. 45

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pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found

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This ETSI Standard (ES) has been produced by ETSI Technical Committee Methods for Testing and Specification

The present document relates to the multi-part standard covering the Testing and Test Control Notation version 3, as

The present document defines the "Continuous Signal support" package of TTCN-3. TTCN-3 can be used for the

specification of all types of reactive system tests over a variety of communication ports. Typical areas of application are

protocol testing (including mobile and Internet protocols), service testing (including supplementary services), module

testing, testing of CORBA based platforms, APIs, etc. TTCN-3 is not restricted to conformance testing and can be used

for many other kinds of testing including interoperability, robustness, regression, system and integration testing. The

specification of test suites for physical layer protocols is outside the scope of the present document.

TTCN-3 packages are intended to define additional TTCN-3 concepts, which are not mandatory as concepts in the

TTCN-3 core language, but which are optional as part of a package which is suited for dedicated applications and/or

This package defines concepts for testing systems using continuous signals as opposed to discrete messages and the

characterization of the progression of such signals by use of streams. For both the production as well as the evaluation

of continuous signals the concept of mode is introduced. Also, the signals can be processed as history-traces. Finally,

basic mathematical functions that are useful for analyzing such traces are defined for TTCN-3. It is thus especially

useful for testing systems which communicate with the physical world via sensors and actuators.

While the design of TTCN-3 package has taken into account the consistency of a combined usage of the core language

with a number of packages, the concrete usages of and guidelines for this package in combination with other packages

References are either specific (identified by date of publication and/or edition number or version number) or

non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the

Referenced documents which are not found to be publicly available in the expected location might be found at

NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee

The following referenced documents are necessary for the application of the present document.

[1] ETSI ES 201 873-1 (V4.4.1): "Methods for Testing and Specification (MTS); The Testing and

[2] ETSI ES 201 873-4 (V4.4.1): "Methods for Testing and Specification (MTS); The Testing and

[3] ETSI ES 201 873-5 (V4.4.1): "Methods for Testing and Specification (MTS); The Testing and

[4] ETSI ES 201 873-6 (V4.4.1): "Methods for Testing and Specification (MTS); The Testing and

[5] ISO/IEC 9646-1: "Information technology -- Open Systems Interconnection -- Conformance

The following referenced documents are not necessary for the application of the present document but they assist the

[i.1] ETSI ES 201 873-2: "Methods for Testing and Specification (MTS); The Testing and Test Control

[i.2] ETSI ES 201 873-3: "Methods for Testing and Specification (MTS); The Testing and Test Control

[i.3] ETSI ES 201 873-7 (V4.4.1): "Methods for Testing and Specification (MTS); The Testing and

[i.4] ETSI ES 201 873-8 (V4.4.1): "Methods for Testing and Specification (MTS); The Testing and

[i.5] ETSI ES 201 873-9 (V4.4.1): "Methods for Testing and Specification (MTS); The Testing and

[i.6] ETSI ES 201 873-10 (V4.4.1): "Methods for Testing and Specification (MTS); The Testing and

Test Control Notation version 3; Part 10: TTCN-3 Documentation Comment Specification".

For the purposes of the present document, the terms and definitions given in ES 201 873-1 [1], ES 201 873-4 [2],

For the purposes of the present document, the abbreviations given in ES 201 873-1 [1], ES 201 873-4 [2],

• "TTCN-3:2012 Support for Testing Continuous Signals" - to be used with modules complying

For an implementation claiming to conform to this package version, all features specified in the present document shall

be implemented consistently with the requirements given in the present document and in ES 201 873-1 [1],

If later versions of those parts are available and should be used instead, the compatibility to the package presented in the

Systems can communicate its data or signals, either in discrete form (e.g. as an integer value) or in continuous form

(e.g. real values). With respect to this difference signals are classified into four categories. The categories distinguish

whether the time and value domain of a signal is of discrete or continuous nature:

1) Analogue signals are continuous in the time and value domain. Analogue signals are the most 'natural' signal

category, characterized by physical units (e.g. current, voltage, velocity) and measured with sensors. Typical

examples of the physical quantities used in the area of embedded system development are the vehicle velocity,

the field intensity of a radio station etc. Analogue signals can be described as a piecewise function over time

2) Time quantified signals are discrete signals in the time domain. The signal values are defined only at

predetermined time points (sampling points). Typical examples of time quantified signals are the time-value

pairs of a recorded signal. A typical representation of a time quantified signal is a series or an array of real

numbers. Even if the original signal is a synthetic function it can only be reconstructed from a time quantified

3) Value quantified signals are time-continuous signals with discrete values. Typical examples of a value

quantified signal are data that are derived from analogue signals and which are dedicated to further processing,

e.g. an A/D converted sensor signal that is provided to an electrical control unit.

4) Digital signals are discrete on the time and value domain. If the set of possible signal values includes only two

elements, one speaks about binary signals. Typical examples of binary signals are switching positions or flags.

Thus on a theoretical level, we distinguish between the continuous and discrete evolution of time and values. In a

discrete system, the changes of states are processed at fixed and finite time steps. In a continuous system state changes

occur for infinitesimally small time steps. Important mathematical models for continuous systems are ordinary

differential equations. A mixed system, which shows continuous and discrete dynamics, is known as a hybrid system.

Hybrid systems can be modelled with hybrid automatons. Examples for systems that show such variable dynamics are

often found in the area of embedded control systems e.g. in the automotive and aircraft industry.

In the general case, a test description notation for embedded software systems shall support all of four categories of

signals mentioned above. TTCN-3 currently supports the signal categories (2) and (4). The extension of the language

with respect to a support of the signal categories (1) and (3) is the content of the present document.

TTCN-3 is a procedural testing language, thus test behaviour is defined by algorithms that typically send messages to

ports and receive messages from ports. For the evaluation of different alternatives of expected messages, or timeout

events, the port queues and the timeout queues are frozen when the evaluation starts. This kind of snapshot semantics

guarantees a consistent view on the test system input during an individual evaluation step. Whereas the snapshot

semantics provides means for a pseudo parallel evaluation of messages from several ports, there is no notion of

simultaneous stimulation and time triggered evaluation. To enhance the core language to the requirements of continuous

• the definition of an automaton alike control flow structure to support the specification of hybrid behaviour.

The TTCN-3 extensions defined in this package adopt the concept of a global clock and enhance it with the notion of

sampling and sampled time. As in TTCN-3, all time values are denoted as float values and represent time in seconds.

For sampling we intend to support simple equidistant sampling models as well as dynamic sampling models.

On technical level an equidistant sampling model of the form t=k*bdelta, where t describes the time progress, d

specifies the number of executed sampling steps and, bdelta yields the minimal achievable step size for a given test

system, is used as an overall basis to model equidistant samplings with larger step size or dynamic sampling.

The basic sampling with its minimal step size bdelta is a property of a concrete test system and not intended to be

specified as part of the test case specification. However, as a consequence of this underlying model, a test system is able

to execute user defined samplings if and only if all specified sampling rates at test specification level provide step sizes

When using the TTCN-3 extension defined in this package, each reference to time, either used for the definition and

evaluation of signals but as well by means of ordinary TTCN-3 timers, is considered to completely synchronized to the

For the specification of time-dependent signal sequences, it is necessary to be able to track the passage of time. The

access of time is guaranteed by a globally available clock whose current value can be accessed by means of the now

operator. Time progress starts at the beginning of each test case execution, thus time values are related to the start of the

Evaluation of the now operator yields the current value of the clock which is the duration of time since the start of the

The now operator shall only be applied from within a test case, i.e. by test cases, functions and altsteps executed on test

components. The now operator shall neither directly nor indirectly be called by TTCN-3 control part.

For sampling, a globally valid base sampling rate defined by the test system is provided. In addition, sampling rates can

be set separately and as part of the test specification by means of stepsize attribute.

The StepSizeValue is a string-literal which must contain a decimal number. This number interpreted as seconds is

used as the default rate of sampling values over the stream ports to which are affected by this stepsize attribute. The

actual sampling rate of a specific port can be changed dynamically with the delta operation.

A stepsize attribute can only appear in a with-annotation. A stepsize attribute can be applied to individual

modules, test cases, groups, component types and stream port types and effects either the statements that are contained

in one of these entities or in case of component types and stream port types the respective instances.