SIST ES 201 873-11 V4.8.1:2019

SLOVENSKI STANDARD
SIST ES 201 873-11 V4.8.1:2019
01-januar-2019

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

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

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

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

Modal verbs terminology ............................................................................................................................ 5

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

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

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

2.2 Informative references ............................................................................................................................... 6

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

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

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

4 Introduction ...................................................................................................................................... 8

5 Conformance and compatibility ....................................................................................................... 8

6 Using TTCN-3 as JSON Schema ..................................................................................................... 9

6.1 Approach ................................................................................................................................................... 9

6.2 Validation of JSON Values ....................................................................................................................... 9

6.3 Name conversion rules .............................................................................................................................. 9

6.4 Mapping of JSON Values ........................................................................................................................ 10

6.4.1 JSON Numbers .................................................................................................................................. 10

6.4.2 JSON Strings ..................................................................................................................................... 10

6.4.3 JSON Arrays ...................................................................................................................................... 12

6.4.4 JSON Objects..................................................................................................................................... 13

6.4.5 JSON Literals..................................................................................................................................... 15

7 Using JSON to exchange data between TTCN-3 and other systems ............................................. 15

7.1 General rules ........................................................................................................................................... 15

7.2 JSON representations of TTCN-3 values ................................................................................................ 16

7.2.1 Character strings ................................................................................................................................ 16

7.2.2 Binary Strings .................................................................................................................................... 17

7.2.3 Integer ................................................................................................................................................ 17

7.2.4 Float ................................................................................................................................................... 17

7.2.5 Boolean .............................................................................................................................................. 18

7.2.6 Enumerated ........................................................................................................................................ 18

7.2.7 Verdicttype ........................................................................................................................................ 18

7.2.8 Record and set .................................................................................................................................... 19

7.2.9 Record of, set of and arrays ............................................................................................................... 20

7.2.10 Union and anytype ............................................................................................................................. 20

7.2.11 Object Identifiers ............................................................................................................................... 21

8 JSON representations of TTCN-3 values based on ASN.1 types ................................................... 22

8.1 General rules ........................................................................................................................................... 22

8.2 Character strings ...................................................................................................................................... 22

8.3 Binary strings .......................................................................................................................................... 22

8.4 BOOLEAN .............................................................................................................................................. 22

8.5 ENUMERATED ..................................................................................................................................... 22

8.6 REAL ...................................................................................................................................................... 23

8.7 INTEGER ................................................................................................................................................ 23

8.8 OBJID ..................................................................................................................................................... 23

8.9 NULL ...................................................................................................................................................... 23

8.10 SEQUENCE and SET ............................................................................................................................. 23

8.11 SEQUENCE OF and SET OF ................................................................................................................. 23

8.12 CHOICE and Open Types ....................................................................................................................... 23

Annex A (normative): TTCN-3 module JSON .......................................................................... 24

Annex B (normative): Encoding instructions ............................................................................ 26

B.1 General ........................................................................................................................................... 26

B.2 The JSON encode attribute ............................................................................................................. 26

B.3 Encoding instructions ..................................................................................................................... 26

B.3.1 General rules ........................................................................................................................................... 26

B.3.2 JSON type identification ......................................................................................................................... 27

B.3.3 Normalizing JSON Values ...................................................................................................................... 27

B.3.4 Name as ................................................................................................................................................... 27

B.3.5 Number of fraction digits ........................................................................................................................ 28

B.3.6 Use the Minus sign .................................................................................................................................. 29

B.3.7 Escape as ................................................................................................................................................. 29

B.3.8 Omit as null ............................................................................................................................................. 30

B.3.9 Default ..................................................................................................................................................... 30

B.3.10 As value ................................................................................................................................................... 31

B.3.11 No Type ................................................................................................................................................... 31

B.3.12 Use order ................................................................................................................................................. 31

B.3.13 Error behaviour ....................................................................................................................................... 32

Annex C (informative): Bibliography ........................................................................................... 33

History ...................................................................................................................................................... 34

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

The present document is part 11 of a multi-part deliverable. Full details of the entire series can be found in part 1 [1].

In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and

"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of

"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.

The present document specifies the rules to define schemas for JSON data structures in TTCN-3, to enable testing of

JSON-based systems, interfaces and protocols, and the conversion rules between TTCN-3 [1] and JSON [2] to enable

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: "Methods for Testing and Specification (MTS); The Testing and Test Control

[2] IETF® RFC 7159: "The JavaScript Object Notation (JSON) Data Interchange Format".

[3] ISO/IEC 10646:2017: "Information technology -- Universal Coded Character Set (UCS)".

[5] ETSI ES 201 873-7: "Methods for Testing and Specification (MTS); The Testing and Test Control

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

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

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

[i.1] IETF® draft-handrews-json-schema-validation-00: "JSON Schema Validation: A Vocabulary for

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

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

[i.6] ETSI ES 202 781: "Methods for Testing and Specification (MTS); The Testing and Test Control

Notation version 3; TTCN-3 Language Extensions: Configuration and Deployment Support".

[i.7] ETSI ES 202 782: "Methods for Testing and Specification (MTS); The Testing and Test Control

Notation version 3; TTCN-3 Language Extensions: TTCN-3 Performance and Real Time Testing".

[i.8] ETSI ES 202 784: "Methods for Testing and Specification (MTS); The Testing and Test Control

[i.9] ETSI ES 202 785: "Methods for Testing and Specification (MTS); The Testing and Test Control

[i.10] ETSI ES 202 786: "Methods for Testing and Specification (MTS); The Testing and Test Control

Notation version 3; TTCN-3 Language Extensions: Support of interfaces with continuous signals".

[i.11] ETSI ES 202 789: "Methods for Testing and Specification (MTS); The Testing and Test Control

For the purposes of the present document, the terms and definitions given in ETSI ES 201 873-1 [1] apply.

An increasing number of distributed applications use the JSON to exchange data for various purposes like data bases

queries or updates or event telecommunications operations such as provisioning. The JSON specification [2] defines the

syntax and encoding for JSON types and defined literals, but no semantics is defined. JSON does not have a schema

specification, like the XML Schema Definition Language used for XML documents (see [i.2] and [i.3]).

NOTE: Though an IETF® draft proposal exists for JSON structural validation (see [i.1]), it has not reached the

The core language of TTCN-3 is defined in ETSI ES 201 873-1 [1] and provides a full text-based syntax, static

semantics and operational semantics. Other parts of the ETSI ES 201 873 series are defining its use with other

specification languages like ASN.1 [5], IDL [i.4], or XSD [i.5] as shown in figure 1, while other documents as ETSI

ES 202 781 [i.6], ETSI ES 202 782 [i.7], ETSI ES 202 784 [i.8], ETSI ES 202 785 [i.9], ETSI ES 202 786 [i.10] and

ETSI ES 202 789 [i.11] specify language extensions and thus can define additional rules to the JSON/TTCN-3 mapping

1) TTCN-3 can be used as a JSON Schema definition language that allows generating JSON values from

TTCN-3 and consuming and evaluating received JSON values, i.e. enables testing of JSON-based interfaces

2) To exchange type and data information between the TTCN-3 test system and systems written in other

languages like Java, C, C++, Python, etc. In this way TTCN-3 test systems can be used as a subsystem of a

more complex test system; for example, the TTCN-3 system receiving contents of messages to be sent to an

SUT, encode and send a message, receive and process the response and report the result to the other system.

Consequently, there is a need to specify mappings between JSON and TTCN-3 for the above purposes.

For an implementation claiming to support the use of TTCN-3 as a JSON schema language, all features specified in

clause 6 of the present document shall be implemented consistently with the requirements given in clause 6 and

For an implementation claiming to support the exchange of TTCN-3-based data between systems, and not supporting

using ASN.1 with TTCN-3, all features specified in clause 7 of the present document, with the exception of the

mapping of the objid type in clause 7.2.11 shall be implemented consistently with the requirements given in clause 7

and Annex B of the present document and in ETSI ES 201 873-1 [1]. Implementations claiming the support of using

ASN.1 with TTCN-3, shall in addition support features in clause 7.2.11 and clause 8 of the present document.

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

JSON [2] defines a limited set of JSON types and literal values. The clauses below define the TTCN-3 types that can be

used to specify a Schema for any JSON interface specification. The TTCN-3 types defined in the clauses below will

allow to use the same set of values as JSON permits. Annex A provides a TTCN-3 module containing all TTCN-3

definitions specified in these clauses. The JSON module in Annex A shall either explicitly be present in TTCN-3 test

suites or TTCN-3 tools shall support these types implicitly. This is left as a tool implementation option.

JSON in many cases allows different encoding options for the same value. These may be controlled by the JSON

encoding instructions specified in Annex B. JSON encoding instructions may be added to TTCN-3 types and fields by

The current version of the JSON specification [2] uses names to identify JSON object members only. The present

document defines JSON to TTCN-3 name conversion rules that shall be used when using TTCN-3 to specify a schema for

a JSON interface (see for example clause 6.4.4). When the JSON and the TTCN-3 names differ after applying the rules in

this clause, the "name as …" encoding instruction shall be used to identify the exact JSON name. To ensure compatibility

with future versions and automatic conversions, the rules specified in this clause should always be applied.

JSON names can be identical to TTCN-3 reserved words, can contain characters not allowed in TTCN-3 identifiers or

allowed to be identical, when the corresponding TTCN-3 names are required to be unique, in which case the JSON

names shall be processed by the rules below to obtain the corresponding TTCN-3 identifiers.

The following character substitutions shall be applied, in order that each character string being mapped to a TTCN-3

name, where each substitution (except the first) shall be applied to the result of the previous transformation:

a) any character except "A" to "Z" (Latin Capital Letter A to Latin Capital Letter Z), "a" to "z" (Latin Small

Letter A to Latin Small Letter Z), "0" to "9" (Digit Zero to Digit Nine), and "_" (Low Line) shall be removed;

b) a sequence of two or more "_" (Low Line) characters shall be replaced with a single "_" (Low Line);

c) "_" (Low Line) characters occurring at the beginning or at the end of the name shall be removed;

d) if a character string starts with a digit (Digit Zero to Digit Nine), it shall be prefixed with an "x" (Latin Small

e) if a character string is empty, it shall be replaced by "x" (Latin Small Letter X);

f) if the TTCN-3 name being generated is identical to a previously generated TTCN-3 identifier in the same

scope, then a postfix shall be appended to the character string generated by the above rules. If a field name of a

TTCN-3 structured type is clashing with a type's name used in the same structured type, the field's name shall

be postfixed. The postfix shall consist of a "_" (Low Line) followed by an integer. This integer shall be the

least positive integer such that the new identifier is different from the identifier of any previously generated

identifier in the same scope (i.e. the first postfix applied by this mechanism is "_1"). TTCN-3 names that are

one of the TTCN-3 keywords (see clause A.1.5 of ETSI ES 201 873-1 [1]) or names of predefined functions

(see clause 16.1.2 of ETSI ES 201 873-1 [1]) after applying the postfix to clashing names, shall be suffixed by

JSON numbers are represented as base 10 decimal digits containing a mandatory integer component that can be

prefixed with an optional minus sign, and can be followed by a fraction part, an exponent part or both. Leading zeros

are not allowed. JSON does not distinguish numbers based on their value sets like integers and reals, like other

In the general case, JSON numbers shall be mapped by using the following TTCN-3 type: