Methods for Testing and Specification (MTS) - The Testing and Test Control Notation version 3 - Part 11: Using JSON with TTCN-3

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
exchanging TTCN-3 data in JSON format between different systems.

Metode za preskušanje in specificiranje (MTS) - 3. različica zapisa preskušanja in krmiljenja preskusov - 11. del: Uporaba JSON v TTCN-3

General Information

Status
Published
Publication Date
17-Jun-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
10-Jun-2021
Due Date
15-Aug-2021
Completion Date
18-Jun-2021

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ETSI ES 201 873-11 V4.9.1 (2021-06)
ETSI STANDARD
Methods for Testing and Specification (MTS);
The Testing and Test Control Notation version 3;
Part 11: Using JSON with TTCN-3
---------------------- Page: 1 ----------------------
2 ETSI ES 201 873-11 V4.9.1 (2021-06)
Reference
RES/MTS-201873-11 v4.9.1
Keywords
JSON, language, testing, TTCN-3
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE
Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16
Siret N° 348 623 562 00017 - APE 7112B
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° w061004871
Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search

The present document may be made available in electronic versions and/or in print. The content of any electronic and/or

print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any

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Users of the present document should be aware that the document may be subject to revision or change of status.

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other professional standard and applicable regulations.

No recommendation as to products and services or vendors is made or should be implied.

No representation or warranty is made that this deliverable is technically accurate or sufficient or conforms to any law

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In no event shall ETSI be held liable for loss of profits or any other incidental or consequential damages.

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of or inability to use the software.
Copyright Notification

No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and

microfilm except as authorized by written permission of ETSI.

The content of the PDF version shall not be modified without the written authorization of ETSI.

The copyright and the foregoing restriction extend to reproduction in all media.
© ETSI 2021.
All rights reserved.
ETSI
---------------------- Page: 2 ----------------------
3 ETSI ES 201 873-11 V4.9.1 (2021-06)
Contents

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 Definition of terms, symbols and abbreviations ............................................................................... 7

3.1 Terms ......................................................................................................................................................... 7

3.2 Symbols ..................................................................................................................................................... 7

3.3 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 ..................................................................................................................................... 11

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 ............................................. 16

7.1 General rules ........................................................................................................................................... 16

7.2 JSON representations of TTCN-3 values ................................................................................................ 17

7.2.1 Character strings ................................................................................................................................ 17

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

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

7.2.4 Float ................................................................................................................................................... 18

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

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

7.2.7 Verdicttype ........................................................................................................................................ 19

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

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

7.2.10 Union and anytype ............................................................................................................................. 21

7.2.11 Object Identifiers ............................................................................................................................... 22

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

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

8.2 Character strings ...................................................................................................................................... 23

8.3 Binary strings .......................................................................................................................................... 23

8.4 BOOLEAN .............................................................................................................................................. 23

8.5 ENUMERATED ..................................................................................................................................... 23

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

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

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

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

8.10 SEQUENCE and SET ............................................................................................................................. 24

8.11 SEQUENCE OF and SET OF ................................................................................................................. 24

8.12 CHOICE and Open Types ....................................................................................................................... 24

Annex A (normative): TTCN-3 module JSON .......................................................................... 25

ETSI
---------------------- Page: 3 ----------------------
4 ETSI ES 201 873-11 V4.9.1 (2021-06)

Annex B (normative): Encoding instructions ............................................................................ 27

B.1 General ........................................................................................................................................... 27

B.2 The JSON encode attribute ............................................................................................................. 27

B.3 Encoding instructions ..................................................................................................................... 27

B.3.1 General rules ........................................................................................................................................... 27

B.3.2 JSON type identification ......................................................................................................................... 28

B.3.3 Normalizing JSON Values ...................................................................................................................... 28

B.3.4 Name as ................................................................................................................................................... 28

B.3.5 Number of fraction digits ........................................................................................................................ 29

B.3.6 Use the Minus sign .................................................................................................................................. 30

B.3.7 Escape as ................................................................................................................................................. 30

B.3.8 Omit as null ............................................................................................................................................. 31

B.3.9 Default ..................................................................................................................................................... 31

B.3.10 As value ................................................................................................................................................... 32

B.3.11 No Type ................................................................................................................................................... 33

B.3.12 Use order ................................................................................................................................................. 33

B.3.13 Error behaviour ....................................................................................................................................... 33

Annex C (informative): Bibliography ........................................................................................... 35

History ...................................................................................................................................................... 36

ETSI
---------------------- Page: 4 ----------------------
5 ETSI ES 201 873-11 V4.9.1 (2021-06)
Intellectual Property Rights
Essential patents

IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations

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

found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to

ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the

ETSI Web server (https://ipr.etsi.org/).

Pursuant to the ETSI Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,

including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not

referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become,

essential to the present document.
Trademarks

The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.

ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no

right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does

not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its

Members. 3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and of the 3GPP

Organizational Partners. oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and of the

oneM2M Partners. GSM and the GSM logo are trademarks registered and owned by the GSM Association.

Foreword

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

(MTS).

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

Modal verbs terminology

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

provisions).

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

ETSI
---------------------- Page: 5 ----------------------
6 ETSI ES 201 873-11 V4.9.1 (2021-06)
1 Scope

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

exchanging TTCN-3 data in JSON format between different systems.
2 References
2.1 Normative references

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 document (including any amendments) applies.

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

https://docbox.etsi.org/Reference/.

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

their long term validity.

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

Notation version 3; Part 1: TTCN-3 Core Language".

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

NOTE: Available at http://www.rfc-editor.org/rfc/rfc7159.txt.

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

NOTE: Available at https://www.iso.org/standard/69119.html.
[4] IEEE 754 : "IEEE Standard for Floating-Point Arithmetic".

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

Notation version 3; Part 7: Using ASN.1 with TTCN-3".
2.2 Informative references

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 document (including any amendments) applies.

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

their long term validity.

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

user with regard to a particular subject area.

draft-handrews-json-schema-validation-00: "JSON Schema Validation: A Vocabulary for

[i.1] IETF
Structural Validation of JSON".
NOTE: Available at https://datatracker.ietf.org/doc/draft-handrews-json-schema.
[i.2] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 1: Structures".
NOTE: Available at http://www.w3.org/TR/xmlschema11-1.
ETSI
---------------------- Page: 6 ----------------------
7 ETSI ES 201 873-11 V4.9.1 (2021-06)
[i.3] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 2: Datatypes".
NOTE: Available at http://www.w3.org/TR/xmlschema11-2.

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

Notation version 3; Part 8: The IDL to TTCN-3 Mapping".

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

Notation version 3; Part 9: Using XML schema with TTCN-3".

[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

Notation version 3; TTCN-3 Language Extensions: Advanced Parameterization".

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

Notation version 3; TTCN-3 Language Extensions: Behaviour Types".

[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

Notation version 3; TTCN-3 Language Extensions: Extended TRI".

[i.12] ETSI ES 203 022: "Methods for Testing and Specification (MTS); The Testing and Test Control

Notation version 3; TTCN-3 Language extension: Advanced Matching".

[i.13] ETSI ES 203 790: "Methods for Testing and Specification (MTS); The Testing and Test Control

Notation version 3; TTCN-3 Language Extensions: Object-Oriented Features".
3 Definition of terms, symbols and abbreviations
3.1 Terms

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

3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ASN.1 Abstract Syntax Notation One
IO ASN.1 Information Object
JSON JavaScript Object Notation
SUT System Under Test
TTCN-3 Testing and Test Control Notation version 3
UCS Universal Coded Character Set
USI UCS Sequence Identifier
UTF-8 Unicode Transformation Format-8
XML eXtensible Markup Language
XSD XML Schema Definition
ETSI
---------------------- Page: 7 ----------------------
8 ETSI ES 201 873-11 V4.9.1 (2021-06)
4 Introduction

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

RFC status.

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],

ETSI ES 202 789 [i.11], ETSI ES 203 022 [i.12] and ETSI ES 203 790 [i.13] specify language extensions and thus can

define additional rules to the JSON/TTCN-3 mapping defined in the present document.

Configuration Advanced OO
Advanced Behavior Performance Continuous TTCN-3
and deploy-
Matching Features
Parameteri- Types and Real signals Packages
ment support
zation Time Testing
ASN.1 types
and values
IDL types
TTCN-3
XML types
Core
TTCN-3 User
Language
JSON types
& values
The shaded boxes are not
defined in this document
Other types &
values
Figure 1: User's view of the core language and its packages
In the context of TTCN-3, JSON can be used for different purposes:

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

and protocols.

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.

5 Conformance and compatibility

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

Annex B of the present document and in ETSI ES 201 873-1 [1].
ETSI
---------------------- Page: 8 ----------------------
9 ETSI ES 201 873-11 V4.9.1 (2021-06)

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.

The language mappings presented in the present document is compatible to:
• ETSI ES 201 873-1 [1], version 4.9.1.

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

present document shall be checked individually.
6 Using TTCN-3 as JSON Schema
6.1 Approach

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

using TTCN-3 variant attributes (see ETSI ES 201 873-1 [1], clause 27.5).
6.2 Validation of JSON Values
For further study.
6.3 Name conversion rules

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

Letter X) character;

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

ETSI
---------------------- Page: 9 ----------------------
10 ETSI ES 201 873-11 V4.9.1 (2021-06)

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
...

Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)
ETSI STANDARD
Methods for Testing and Specification (MTS);
The Testing and Test Control Notation version 3;
Part 11: Using JSON with TTCN-3
---------------------- Page: 1 ----------------------
2 Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)
Reference
RES/MTS-201873-11 v4.9.1
Keywords
JSON, language, testing, TTCN-3
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE
Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16
Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88
Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search

The present document may be made available in electronic versions and/or in print. The content of any electronic and/or

print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any

existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI

deliverable is the one made publicly available in PDF format at www.etsi.org/deliver.

Users of the present document should be aware that the document may be subject to revision or change of status.

Information on the current status of this and other ETSI documents is available at

https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx

If you find errors in the present document, please send your comment to one of the following services:

https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification

No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying

and microfilm except as authorized by written permission of ETSI.

The content of the PDF version shall not be modified without the written authorization of ETSI.

The copyright and the foregoing restriction extend to reproduction in all media.
© ETSI 2021.
All rights reserved.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.

3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and

of the 3GPP Organizational Partners.

oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and

of the oneM2M Partners.
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI
---------------------- Page: 2 ----------------------
3 Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)
Contents

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 Definition of terms, symbols and abbreviations ............................................................................... 7

3.1 Terms ......................................................................................................................................................... 7

3.2 Symbols ..................................................................................................................................................... 7

3.3 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 ..................................................................................................................................... 11

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 ............................................. 16

7.1 General rules ........................................................................................................................................... 16

7.2 JSON representations of TTCN-3 values ................................................................................................ 17

7.2.1 Character strings ................................................................................................................................ 17

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

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

7.2.4 Float ................................................................................................................................................... 18

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

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

7.2.7 Verdicttype ........................................................................................................................................ 19

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

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

7.2.10 Union and anytype ............................................................................................................................. 21

7.2.11 Object Identifiers ............................................................................................................................... 22

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

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

8.2 Character strings ...................................................................................................................................... 23

8.3 Binary strings .......................................................................................................................................... 23

8.4 BOOLEAN .............................................................................................................................................. 23

8.5 ENUMERATED ..................................................................................................................................... 23

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

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

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

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

8.10 SEQUENCE and SET ............................................................................................................................. 24

8.11 SEQUENCE OF and SET OF ................................................................................................................. 24

8.12 CHOICE and Open Types ....................................................................................................................... 24

Annex A (normative): TTCN-3 module JSON .......................................................................... 25

ETSI
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4 Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)

Annex B (normative): Encoding instructions ............................................................................ 27

B.1 General ........................................................................................................................................... 27

B.2 The JSON encode attribute ............................................................................................................. 27

B.3 Encoding instructions ..................................................................................................................... 27

B.3.1 General rules ........................................................................................................................................... 27

B.3.2 JSON type identification ......................................................................................................................... 28

B.3.3 Normalizing JSON Values ...................................................................................................................... 28

B.3.4 Name as ................................................................................................................................................... 28

B.3.5 Number of fraction digits ........................................................................................................................ 29

B.3.6 Use the Minus sign .................................................................................................................................. 30

B.3.7 Escape as ................................................................................................................................................. 30

B.3.8 Omit as null ............................................................................................................................................. 31

B.3.9 Default ..................................................................................................................................................... 31

B.3.10 As value ................................................................................................................................................... 32

B.3.11 No Type ................................................................................................................................................... 33

B.3.12 Use order ................................................................................................................................................. 33

B.3.13 Error behaviour ....................................................................................................................................... 33

Annex C (informative): Bibliography ........................................................................................... 35

History ...................................................................................................................................................... 36

ETSI
---------------------- Page: 4 ----------------------
5 Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)
Intellectual Property Rights
Essential patents

IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information

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

in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in

respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web

server (https://ipr.etsi.org/).

Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee

can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web

server) which are, or may be, or may become, essential to the present document.
Trademarks

The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.

ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no

right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does

not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.

Foreword

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

Specification (MTS), and is now submitted for the ETSI standards Membership Approval Procedure.

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

Modal verbs terminology

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

provisions).

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

ETSI
---------------------- Page: 5 ----------------------
6 Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)
1 Scope

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

exchanging TTCN-3 data in JSON format between different systems.
2 References
2.1 Normative references

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 document (including any amendments) applies.

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

https://docbox.etsi.org/Reference/.

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

their long term validity.

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

Notation version 3; Part 1: TTCN-3 Core Language".

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

NOTE: Available at http://www.rfc-editor.org/rfc/rfc7159.txt.

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

NOTE: Available at https://www.iso.org/standard/69119.html.
[4] IEEE 754 : "IEEE Standard for Floating-Point Arithmetic".

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

Notation version 3; Part 7: Using ASN.1 with TTCN-3".
2.2 Informative references

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 document (including any amendments) applies.

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

their long term validity.

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

user with regard to a particular subject area.

draft-handrews-json-schema-validation-00: "JSON Schema Validation: A Vocabulary for

[i.1] IETF
Structural Validation of JSON".
NOTE: Available at https://datatracker.ietf.org/doc/draft-handrews-json-schema.
[i.2] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 1: Structures".
NOTE: Available at http://www.w3.org/TR/xmlschema11-1.
ETSI
---------------------- Page: 6 ----------------------
7 Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)
[i.3] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 2: Datatypes".
NOTE: Available at http://www.w3.org/TR/xmlschema11-2.

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

Notation version 3; Part 8: The IDL to TTCN-3 Mapping".

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

Notation version 3; Part 9: Using XML schema with TTCN-3".

[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

Notation version 3; TTCN-3 Language Extensions: Advanced Parameterization".

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

Notation version 3; TTCN-3 Language Extensions: Behaviour Types".

[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

Notation version 3; TTCN-3 Language Extensions: Extended TRI".

[i.12] ETSI ES 203 022: "Methods for Testing and Specification (MTS); The Testing and Test Control

Notation version 3; TTCN-3 Language extension: Advanced Matching".

[i.13] ETSI ES 203 790: "Methods for Testing and Specification (MTS); The Testing and Test Control

Notation version 3; TTCN-3 Language Extensions: Object-Oriented Features".
3 Definition of terms, symbols and abbreviations
3.1 Terms

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

3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ASN.1 Abstract Syntax Notation One
IO ASN.1 Information Object
JSON JavaScript Object Notation
SUT System Under Test
TTCN-3 Testing and Test Control Notation version 3
UCS Universal Coded Character Set
USI UCS Sequence Identifier
UTF-8 Unicode Transformation Format-8
XML eXtensible Markup Language
XSD XML Schema Definition
ETSI
---------------------- Page: 7 ----------------------
8 Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)
4 Introduction

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

RFC status.

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],

ETSI ES 202 789 [i.11], ETSI ES 203 022 [i.12] and ETSI ES 203 790 [i.13] specify language extensions and thus can

define additional rules to the JSON/TTCN-3 mapping defined in the present document.

Configuration Advanced OO
Advanced Behavior Performance Continuous TTCN-3
and deploy-
Matching Features
Parameteri- Types and Real signals Packages
ment support
zation Time Testing
ASN.1 types
and values
IDL types
TTCN-3
XML types
Core
TTCN-3 User
Language
JSON types
& values
The shaded boxes are not
defined in this document
Other types &
values
Figure 1: User's view of the core language and its packages
In the context of TTCN-3, JSON can be used for different purposes:

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

and protocols.

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.

5 Conformance and compatibility

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

Annex B of the present document and in ETSI ES 201 873-1 [1].
ETSI
---------------------- Page: 8 ----------------------
9 Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)

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.

The language mappings presented in the present document is compatible to:
• ETSI ES 201 873-1 [1], version 4.9.1.

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

present document shall be checked individually.
6 Using TTCN-3 as JSON Schema
6.1 Approach

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

using TTCN-3 variant attributes (see ETSI ES 201 873-1 [1], clause 27.5).
6.2 Validation of JSON Values
For further study.
6.3 Name conversion rules

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

Letter X) character;

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

ETSI
---------------------- Page: 9 ----------------------
10 Final draft ETSI ES 201 873-11 V4.9.1 (2021-03)

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

a single "_" (Low Line) character.
6.4 Mapping of JSON Values
6.4.1 JSON Numbers

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

languages do. No special values (as –infinity, infinity or NaN) are allowed.

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

type float Number (!-infinity .. !infinity) with {
variant "JSON:number"
}

When the JSON interface specification requires a number to conform to the IEEE 754 [4] floating-point number

specification, the IEEE 754 floats useful types of clause E.2.1.4 of ETSI ES 201 873-1 [1] can be used in the context of

JSON encoding, in which case, by default, the given useful type will constrain the value set and the encoding of the

JSON value according to this clause. The JSON encoding inst
...

SLOVENSKI STANDARD
SIST ES 201 873-11 V4.9.1:2021
01-september-2021

Metode za preskušanje in specificiranje (MTS) - 3. različica zapisa preskušanja in

krmiljenja preskusov - 11. del: Uporaba JSON v TTCN-3

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

version 3 - Part 11: Using JSON with TTCN-3
Ta slovenski standard je istoveten z: ETSI ES 201 873-11 V4.9.1 (2021-06)
ICS:
33.040.01 Telekomunikacijski sistemi na Telecommunication systems
splošno in general
35.060 Jeziki, ki se uporabljajo v Languages used in
informacijski tehniki in information technology
tehnologiji
SIST ES 201 873-11 V4.9.1:2021 en

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

---------------------- Page: 1 ----------------------
SIST ES 201 873-11 V4.9.1:2021
---------------------- Page: 2 ----------------------
SIST ES 201 873-11 V4.9.1:2021
ETSI ES 201 873-11 V4.9.1 (2021-06)
ETSI STANDARD
Methods for Testing and Specification (MTS);
The Testing and Test Control Notation version 3;
Part 11: Using JSON with TTCN-3
---------------------- Page: 3 ----------------------
SIST ES 201 873-11 V4.9.1:2021
2 ETSI ES 201 873-11 V4.9.1 (2021-06)
Reference
RES/MTS-201873-11 v4.9.1
Keywords
JSON, language, testing, TTCN-3
ETSI
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All rights reserved.
ETSI
---------------------- Page: 4 ----------------------
SIST ES 201 873-11 V4.9.1:2021
3 ETSI ES 201 873-11 V4.9.1 (2021-06)
Contents

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 Definition of terms, symbols and abbreviations ............................................................................... 7

3.1 Terms ......................................................................................................................................................... 7

3.2 Symbols ..................................................................................................................................................... 7

3.3 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 ..................................................................................................................................... 11

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 ............................................. 16

7.1 General rules ........................................................................................................................................... 16

7.2 JSON representations of TTCN-3 values ................................................................................................ 17

7.2.1 Character strings ................................................................................................................................ 17

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

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

7.2.4 Float ................................................................................................................................................... 18

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

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

7.2.7 Verdicttype ........................................................................................................................................ 19

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

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

7.2.10 Union and anytype ............................................................................................................................. 21

7.2.11 Object Identifiers ............................................................................................................................... 22

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

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

8.2 Character strings ...................................................................................................................................... 23

8.3 Binary strings .......................................................................................................................................... 23

8.4 BOOLEAN .............................................................................................................................................. 23

8.5 ENUMERATED ..................................................................................................................................... 23

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

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

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

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

8.10 SEQUENCE and SET ............................................................................................................................. 24

8.11 SEQUENCE OF and SET OF ................................................................................................................. 24

8.12 CHOICE and Open Types ....................................................................................................................... 24

Annex A (normative): TTCN-3 module JSON .......................................................................... 25

ETSI
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SIST ES 201 873-11 V4.9.1:2021
4 ETSI ES 201 873-11 V4.9.1 (2021-06)

Annex B (normative): Encoding instructions ............................................................................ 27

B.1 General ........................................................................................................................................... 27

B.2 The JSON encode attribute ............................................................................................................. 27

B.3 Encoding instructions ..................................................................................................................... 27

B.3.1 General rules ........................................................................................................................................... 27

B.3.2 JSON type identification ......................................................................................................................... 28

B.3.3 Normalizing JSON Values ...................................................................................................................... 28

B.3.4 Name as ................................................................................................................................................... 28

B.3.5 Number of fraction digits ........................................................................................................................ 29

B.3.6 Use the Minus sign .................................................................................................................................. 30

B.3.7 Escape as ................................................................................................................................................. 30

B.3.8 Omit as null ............................................................................................................................................. 31

B.3.9 Default ..................................................................................................................................................... 31

B.3.10 As value ................................................................................................................................................... 32

B.3.11 No Type ................................................................................................................................................... 33

B.3.12 Use order ................................................................................................................................................. 33

B.3.13 Error behaviour ....................................................................................................................................... 33

Annex C (informative): Bibliography ........................................................................................... 35

History ...................................................................................................................................................... 36

ETSI
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SIST ES 201 873-11 V4.9.1:2021
5 ETSI ES 201 873-11 V4.9.1 (2021-06)
Intellectual Property Rights
Essential patents

IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations

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

found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to

ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the

ETSI Web server (https://ipr.etsi.org/).

Pursuant to the ETSI Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,

including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not

referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become,

essential to the present document.
Trademarks

The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.

ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no

right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does

not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its

Members. 3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and of the 3GPP

Organizational Partners. oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and of the

oneM2M Partners. GSM and the GSM logo are trademarks registered and owned by the GSM Association.

Foreword

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

(MTS).

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

Modal verbs terminology

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

provisions).

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

ETSI
---------------------- Page: 7 ----------------------
SIST ES 201 873-11 V4.9.1:2021
6 ETSI ES 201 873-11 V4.9.1 (2021-06)
1 Scope

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

exchanging TTCN-3 data in JSON format between different systems.
2 References
2.1 Normative references

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 document (including any amendments) applies.

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

https://docbox.etsi.org/Reference/.

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

their long term validity.

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

Notation version 3; Part 1: TTCN-3 Core Language".

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

NOTE: Available at http://www.rfc-editor.org/rfc/rfc7159.txt.

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

NOTE: Available at https://www.iso.org/standard/69119.html.
[4] IEEE 754 : "IEEE Standard for Floating-Point Arithmetic".

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

Notation version 3; Part 7: Using ASN.1 with TTCN-3".
2.2 Informative references

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 document (including any amendments) applies.

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

their long term validity.

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

user with regard to a particular subject area.

draft-handrews-json-schema-validation-00: "JSON Schema Validation: A Vocabulary for

[i.1] IETF
Structural Validation of JSON".
NOTE: Available at https://datatracker.ietf.org/doc/draft-handrews-json-schema.
[i.2] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 1: Structures".
NOTE: Available at http://www.w3.org/TR/xmlschema11-1.
ETSI
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[i.3] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 2: Datatypes".
NOTE: Available at http://www.w3.org/TR/xmlschema11-2.

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

Notation version 3; Part 8: The IDL to TTCN-3 Mapping".

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

Notation version 3; Part 9: Using XML schema with TTCN-3".

[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

Notation version 3; TTCN-3 Language Extensions: Advanced Parameterization".

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

Notation version 3; TTCN-3 Language Extensions: Behaviour Types".

[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

Notation version 3; TTCN-3 Language Extensions: Extended TRI".

[i.12] ETSI ES 203 022: "Methods for Testing and Specification (MTS); The Testing and Test Control

Notation version 3; TTCN-3 Language extension: Advanced Matching".

[i.13] ETSI ES 203 790: "Methods for Testing and Specification (MTS); The Testing and Test Control

Notation version 3; TTCN-3 Language Extensions: Object-Oriented Features".
3 Definition of terms, symbols and abbreviations
3.1 Terms

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

3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ASN.1 Abstract Syntax Notation One
IO ASN.1 Information Object
JSON JavaScript Object Notation
SUT System Under Test
TTCN-3 Testing and Test Control Notation version 3
UCS Universal Coded Character Set
USI UCS Sequence Identifier
UTF-8 Unicode Transformation Format-8
XML eXtensible Markup Language
XSD XML Schema Definition
ETSI
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4 Introduction

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

RFC status.

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],

ETSI ES 202 789 [i.11], ETSI ES 203 022 [i.12] and ETSI ES 203 790 [i.13] specify language extensions and thus can

define additional rules to the JSON/TTCN-3 mapping defined in the present document.

Configuration Advanced OO
Advanced Behavior Performance Continuous TTCN-3
and deploy-
Matching Features
Parameteri- Types and Real signals Packages
ment support
zation Time Testing
ASN.1 types
and values
IDL types
TTCN-3
XML types
Core
TTCN-3 User
Language
JSON types
& values
The shaded boxes are not
defined in this document
Other types &
values
Figure 1: User's view of the core language and its packages
In the context of TTCN-3, JSON can be used for different purposes:

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

and protocols.

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.

5 Conformance and compatibility

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

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

The language mappings presented in the present document is compatible to:
• ETSI ES 201 873-1 [1], version 4.9.1.

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

present document shall be checked individually.
6 Using TTCN-3 as JSON Schema
6.1 Approach

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

using TTCN-3 variant attributes (see ETSI ES 201 873-1 [1], clause 27.5).
6.2 Validation of JSON Values
For further study.
6.3 Name conversion rules

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) charac
...

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