ETSI ES 201 873-11 V4.10.1 (2023-05)

Final draft ETSI ES 201 873-11 V4.10.1 (2023-03)






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

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2 Final draft ETSI ES 201 873-11 V4.10.1 (2023-03)

Reference
RES/MTS-20187311v4.10.1
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
existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI
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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
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If you find errors in the present document, please send your comment to one of the following services:
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If you find a security vulnerability in the present document, please report it through our
Coordinated Vulnerability Disclosure Program:
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Notice of disclaimer & limitation of liability
The information provided in the present deliverable is directed solely to professionals who have the appropriate degree of
experience to understand and interpret its content in accordance with generally accepted engineering or
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
and/or governmental rule and/or regulation and further, no representation or warranty is made of merchantability or fitness
for any particular purpose or against infringement of intellectual property rights.
In no event shall ETSI be held liable for loss of profits or any other incidental or consequential damages.

Any software contained in this deliverable is provided "AS IS" with no warranties, express or implied, including but not
limited to, the warranties of merchantability, fitness for a particular purpose and non-infringement of intellectual property
rights and ETSI shall not be held liable in any event for any damages whatsoever (including, without limitation, damages
for loss of profits, business interruption, loss of information, or any other pecuniary loss) arising out of or related to the use
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 2023.
All rights reserved.

ETSI

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3 Final draft ETSI ES 201 873-11 V4.10.1 (2023-03)
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 V4.10.1 (2023-03)
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

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5 Final draft ETSI ES 201 873-11 V4.10.1 (2023-03)
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 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

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6 Final draft ETSI ES 201 873-11 V4.10.1 (2023-03)
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".
[3] ISO/IEC 10646:2017: "Information technology -- Universal Coded Character Set (UCS)".
[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.
[i.1] IETF draft-handrews-json-schema-validation-00: "JSON Schema Validation: A Vocabulary for
Structural Validation of JSON".
®
[i.2] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 1: Structures".
®
[i.3] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 2: Datatypes".
[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".
ETSI

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7 Final draft ETSI ES 201 873-11 V4.10.1 (2023-03)
[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: 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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8 Final draft ETSI ES 201 873-11 V4.10.1 (2023-03)
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

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9 Final draft ETSI ES 201 873-11 V4.10.1 (2023-03)
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

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10 Final draft ETSI ES 201 873-11 V4.10.1 (2023-03)
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
...

SLOVENSKI STANDARD
SIST ES 201 873-11 V4.10.1:2023
01-junij-2023
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 V4.10.1 (2023-05)
ICS:
33.040.01 Telekomunikacijski sistemi Telecommunication systems
na splošno in general
35.060 Jeziki, ki se uporabljajo v Languages used in
informacijski tehniki in information technology
tehnologiji
SIST ES 201 873-11 V4.10.1:2023 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ES 201 873-11 V4.10.1:2023

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SIST ES 201 873-11 V4.10.1:2023
ETSI ES 201 873-11 V4.10.1 (2023-05)






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

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SIST ES 201 873-11 V4.10.1:2023
 2 ETSI ES 201 873-11 V4.10.1 (2023-05)

Reference
RES/MTS-20187311v4.10.1
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:
https://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
If you find a security vulnerability in the present document, please report it through our
Coordinated Vulnerability Disclosure Program:
https://www.etsi.org/standards/coordinated-vulnerability-disclosure
Notice of disclaimer & limitation of liability
The information provided in the present deliverable is directed solely to professionals who have the appropriate degree of
experience to understand and interpret its content in accordance with generally accepted engineering or
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
and/or governmental rule and/or regulation and further, no representation or warranty is made of merchantability or fitness
for any particular purpose or against infringement of intellectual property rights.
In no event shall ETSI be held liable for loss of profits or any other incidental or consequential damages.

Any software contained in this deliverable is provided "AS IS" with no warranties, express or implied, including but not
limited to, the warranties of merchantability, fitness for a particular purpose and non-infringement of intellectual property
rights and ETSI shall not be held liable in any event for any damages whatsoever (including, without limitation, damages
for loss of profits, business interruption, loss of information, or any other pecuniary loss) arising out of or related to the use
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 2023.
All rights reserved.

ETSI

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SIST ES 201 873-11 V4.10.1:2023
 3 ETSI ES 201 873-11 V4.10.1 (2023-05)
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 V4.10.1:2023
 4 ETSI ES 201 873-11 V4.10.1 (2023-05)
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 V4.10.1:2023
 5 ETSI ES 201 873-11 V4.10.1 (2023-05)
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/).
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essential to the present document.
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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

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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".
[3] ISO/IEC 10646:2017: "Information technology -- Universal Coded Character Set (UCS)".
[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.
[i.1] IETF draft-handrews-json-schema-validation-00: "JSON Schema Validation: A Vocabulary for
Structural Validation of JSON".
®
[i.2] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 1: Structures".
®
[i.3] World Wide Web Consortium W3C Recommendation: "W3C XML Schema Definition
Language (XSD) 1.1 Part 2: Datatypes".
[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".
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[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: 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 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
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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) characters shall be replaced with a single "_" (Low Line);
c) "_" (Low Line) characters occurring at the beginning or at the end
...