ETSI ES 201 873-11 V4.7.1 (2017-06)

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

This new part of the standard defines the language mapping between JSON schema and TTCN-3 and additional encoding instructions for JSON data format representation option.

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

Ta novi del standarda določa jezikovno preslikavo med shemo JSON in TTCN-3 ter podaja dodatna navodila za kodiranje za možnost predstavitve podatkovnega formata JSON.

General Information

• Status: Published
• Publication Date: 26-Jun-2017
• Technical Committee: MTS - Methods for Testing & Specification
• Current Stage: 12 - Completion
• Due Date: 10-Jul-2017
• Completion Date: 27-Jun-2017
• Ref Project: SIST ES 201 873-11 V4.7.1:2017 - Methods for Testing and Specification (MTS) - The Testing and Test Control Notation version 3 - Part 11: Using JSON with TTCN-3

Standards Content (Sample)

ETSI ES 201 873-11 V4.7.1 (2017-06)






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 V4.7.1 (2017-06)



Reference
DES/MTS-00201873-11ed471JSON
Keywords
JSON, language, testing, TTCN-3
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

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 only prevailing document is the
print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat.
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 2017.
All rights reserved.

TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M logo is protected for the benefit of its Members
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI

---------------------- Page: 2 ----------------------
3 ETSI ES 201 873-11 V4.7.1 (2017-06)
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 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 7
4 Introduction . 8
5 Conformance and compatibility . 8
6 Using TTCN-3 as JSON Schema . 9
6.1 Approach . 9
6.2 Validation of JSON Values . 9
6.3 Name conversion rules . 9
6.4 Mapping of JSON Values . 10
6.4.1 JSON Numbers . 10
6.4.2 JSON Strings . 11
6.4.3 JSON Arrays . 12
6.4.4 JSON Objects. 14
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 ETSI ES 201 873-11 V4.7.1 (2017-06)
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 . 32
B.3.12 Use order . 32
B.3.13 Error behaviour . 33
Annex C (informative): Bibliography . 34
History . 35

ETSI

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5 ETSI ES 201 873-11 V4.7.1 (2017-06)
Intellectual Property Rights
IPRs essential or potentially essential to the present document 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.
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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6 ETSI ES 201 873-11 V4.7.1 (2017-06)
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 10646:2014: "Information technology -- Universal Coded Character Set (UCS)".
NOTE: Available at http://standards.iso.org/ittf/PubliclyAvailableStandards/c056921_ISO_IEC_10646_2012.zip.
TM
[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-zyp-json-schema-04: "JSON Schema: core definitions and terminology".
[i.1] IETF
NOTE: Available at http://tools.ietf.org/html/draft-zyp-json-schema-04.
®
[i.2] IETF draft-fge-json-schema-validation-00: "JSON Schema: interactive and non interactive
validation".
NOTE: Available at http://tools.ietf.org/html/draft-zyp-json-schema-04.
ETSI

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7 ETSI ES 201 873-11 V4.7.1 (2017-06)
®
[i.3] World Wide Web Consortium W3C Recommendation: "XML Schema Part 1: Structures".
NOTE: Available at http://www.w3.org/TR/xmlschema11-1.
®
[i.4] World Wide Web Consortium W3C Recommendation: "XML Schema Part 2: Datatypes".
NOTE: Available at http://www.w3.org/TR/xmlschema11-2.
[i.5] 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.6] 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.7] 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.8] 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.9] 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.10] 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.11] 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.12] ETSI ES 202 789: "Methods for Testing and Specification (MTS); The Testing and Test Control
Notation version 3; TTCN-3 Language Extensions: Extended TRI".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in ETSI ES 201 873-1 [1] apply.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ASN.1 Abstract Syntax Notation no. 1
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 ETSI ES 201 873-11 V4.7.1 (2017-06)
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.3] and [i.4]).
NOTE: Though an IETF draft proposal exists for JSON schema (see [i.1] and [i.2]), 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.5], or XSD [i.6] as shown in figure 1, while other documents as ETSI
ES 202 781 [i.7], ETSI ES 202 782 [i.8], ETSI ES 202 784 [i.9], ETSI ES 202 785 [i.10], ETSI ES 202 786 [i.11] and
ETSI ES 202 789 [i.12] specify language extensions and thus can define additional rules to the JSON/TTCN-3 mapping
defined in the present document.




JSON Types


& Values

Other

presentation
TTCN-3
formats as
Other Types
Core
defined in
& Values
2
TTCN-3 User
Language
other parts of
the standard
or user-
specific
formats
Other Types Note: The shaded boxes are
& Values
n not defined in this document

Figure 1: User's view of the core language and the various presentation formats
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].
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.
ETSI

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9 ETSI ES 201 873-11 V4.7.1 (2017-06)
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 ETSI ES 201 873-11 V4.7.1 (2017-06)
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.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 ANSI/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 instructions in this case can be applied to fields of IEEE 754
useful types.
By default, i.e. without any encoding instruction applied, the form of the JSON representation of JSON.Number is a
tool implementation option (i.e. the number of fraction digits, using the exponent part, etc.)
To make defining JSON Schemas in TTCN-3 easier, the present document, in addition to the generic mapping of JSON
numbers, also specifies a TTCN-3 type that may be used where the interface specification allows only numbers without
the fraction and the exponent parts:
type integer Integer (-infinity . infinity) with {
 variant "JSON:integer"
}

Attempts to decode a JSON number value with either a fraction or an exponent part or both into this JSON.Integer
type shall cause a decoding failure.
In addition to the generic encoding instructions like "normalize" and "name as …", the following specific instructions
shall be applicable to types and fields of JSON.Number and the IEEE 754 useful types:
• fractionDigits see clause B.3.5
• useMinus  see clause B.3.6
NOTE: The beginning character of the exponent part can be both "e" and "E". This is not controlled by any of the
encoding instructions but left as a tool implementation option.
and to t
...

Final draft ETSI ES 201 873-11 V4.7.1 (2017-04)






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 V4.7.1 (2017-04)



Reference
DES/MTS-00201873-11ed471JSON
Keywords
JSON, language, testing, TTCN-3
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

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 only prevailing document is the
print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat.
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.

© European Telecommunications Standards Institute 2017.
All rights reserved.

TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M logo is protected for the benefit of its Members
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI

---------------------- Page: 2 ----------------------
3 Final draft ETSI ES 201 873-11 V4.7.1 (2017-04)
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 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 7
4 Introduction . 8
5 Conformance and compatibility . 8
6 Using TTCN-3 as JSON Schema . 9
6.1 Approach . 9
6.2 Validation of JSON Values . 9
6.3 Name conversion rules . 9
6.4 Mapping of JSON Values . 10
6.4.1 JSON Numbers . 10
6.4.2 JSON Strings . 11
6.4.3 JSON Arrays . 12
6.4.4 JSON Objects. 14
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 V4.7.1 (2017-04)
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 . 32
B.3.12 Use order . 32
B.3.13 Error behaviour . 33
Annex C (informative): Bibliography . 34
History . 35

ETSI

---------------------- Page: 4 ----------------------
5 Final draft ETSI ES 201 873-11 V4.7.1 (2017-04)
Intellectual Property Rights
IPRs essential or potentially essential to the present document 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.
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 V4.7.1 (2017-04)
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 10646:2014: "Information technology -- Universal Coded Character Set (UCS)".
NOTE: Available at http://standards.iso.org/ittf/PubliclyAvailableStandards/c056921_ISO_IEC_10646_2012.zip.
TM
[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-zyp-json-schema-04: "JSON Schema: core definitions and terminology".
[i.1] IETF
NOTE: Available at http://tools.ietf.org/html/draft-zyp-json-schema-04.
®
[i.2] IETF draft-fge-json-schema-validation-00: "JSON Schema: interactive and non interactive
validation".
NOTE: Available at http://tools.ietf.org/html/draft-zyp-json-schema-04.
ETSI

---------------------- Page: 6 ----------------------
7 Final draft ETSI ES 201 873-11 V4.7.1 (2017-04)
®
[i.3] World Wide Web Consortium W3C Recommendation: "XML Schema Part 1: Structures".
NOTE: Available at http://www.w3.org/TR/xmlschema11-1.
®
[i.4] World Wide Web Consortium W3C Recommendation: "XML Schema Part 2: Datatypes".
NOTE: Available at http://www.w3.org/TR/xmlschema11-2.
[i.5] 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.6] 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.7] 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.8] 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.9] 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.10] 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.11] 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.12] ETSI ES 202 789: "Methods for Testing and Specification (MTS); The Testing and Test Control
Notation version 3; TTCN-3 Language Extensions: Extended TRI".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in ETSI ES 201 873-1 [1] apply.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ASN.1 Abstract Syntax Notation no. 1
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 V4.7.1 (2017-04)
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.3] and [i.4]).
NOTE: Though an IETF draft proposal exists for JSON schema (see [i.1] and [i.2]), 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.5], or XSD [i.6] as shown in figure 1, while other documents as ETSI
ES 202 781 [i.7], ETSI ES 202 782 [i.8], ETSI ES 202 784 [i.9], ETSI ES 202 785 [i.10], ETSI ES 202 786 [i.11] and
ETSI ES 202 789 [i.12] specify language extensions and thus can define additional rules to the JSON/TTCN-3 mapping
defined in the present document.




JSON Types


& Values

Other

presentation
TTCN-3
formats as
Other Types
Core
defined in
& Values
2
TTCN-3 User
Language
other parts of
the standard
or user-
specific
formats
Other Types Note: The shaded boxes are
& Values
n not defined in this document

Figure 1: User's view of the core language and the various presentation formats
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].
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.
ETSI

---------------------- Page: 8 ----------------------
9 Final draft ETSI ES 201 873-11 V4.7.1 (2017-04)
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 V4.7.1 (2017-04)
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 ANSI/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 instructions in this case can be applied to fields of IEEE 754
useful types.
By default, i.e. without any encoding instruction applied, the form of the JSON representation of JSON.Number is a
tool implementation option (i.e. the number of fraction digits, using the exponent part, etc.)
To make defining JSON Schemas in TTCN-3 easier, the present document, in addition to the generic mapping of JSON
numbers, also specifies a TTCN-3 type that may be used where the interface specification allows only numbers without
the fraction and the exponent parts:
type integer Integer (-infinity . infinity) with {
 variant "JSON:integer"
}

Attempts to decode a JSON number value with either a fraction or an exponent part or both into this JSON.Integer
type shall cause a decoding failure.
In addition to the generic encoding instructions like "normalize" and "name as …", the following specific instructions
shall be applicable to types and fields of JSON.Number and the IEEE 754 useful types:
• fr
...

SLOVENSKI STANDARD
SIST ES 201 873-11 V4.7.1:2017
01-september-2017
0HWRGH]DSUHVNXãDQMHLQVSHFLILFLUDQMH076UD]OLþLFD]DSLVDSUHVNXãDQMDLQ
NUPLOMHQMDSUHVNXVRYGHO8SRUDED-621Y77&1
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 V4.7.1 (2017-06)
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 V4.7.1:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST ES 201 873-11 V4.7.1:2017

---------------------- Page: 2 ----------------------

SIST ES 201 873-11 V4.7.1:2017
ETSI ES 201 873-11 V4.7.1 (2017-06)






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 V4.7.1:2017
 2 ETSI ES 201 873-11 V4.7.1 (2017-06)



Reference
DES/MTS-00201873-11ed471JSON
Keywords
JSON, language, testing, TTCN-3
ETSI
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Tel.: [phone]  Fax: [phone]

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Important notice
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© ETSI 2017.
All rights reserved.

TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
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of the 3GPP Organizational Partners.
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ETSI

---------------------- Page: 4 ----------------------

SIST ES 201 873-11 V4.7.1:2017
 3 ETSI ES 201 873-11 V4.7.1 (2017-06)
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 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 7
4 Introduction . 8
5 Conformance and compatibility . 8
6 Using TTCN-3 as JSON Schema . 9
6.1 Approach . 9
6.2 Validation of JSON Values . 9
6.3 Name conversion rules . 9
6.4 Mapping of JSON Values . 10
6.4.1 JSON Numbers . 10
6.4.2 JSON Strings . 11
6.4.3 JSON Arrays . 12
6.4.4 JSON Objects. 14
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: 5 ----------------------

SIST ES 201 873-11 V4.7.1:2017
 4 ETSI ES 201 873-11 V4.7.1 (2017-06)
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 . 32
B.3.12 Use order . 32
B.3.13 Error behaviour . 33
Annex C (informative): Bibliography . 34
History . 35

ETSI

---------------------- Page: 6 ----------------------

SIST ES 201 873-11 V4.7.1:2017
 5 ETSI ES 201 873-11 V4.7.1 (2017-06)
Intellectual Property Rights
IPRs essential or potentially essential to the present document 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.
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 V4.7.1:2017
 6 ETSI ES 201 873-11 V4.7.1 (2017-06)
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 10646:2014: "Information technology -- Universal Coded Character Set (UCS)".
NOTE: Available at http://standards.iso.org/ittf/PubliclyAvailableStandards/c056921_ISO_IEC_10646_2012.zip.
TM
[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-zyp-json-schema-04: "JSON Schema: core definitions and terminology".
[i.1] IETF
NOTE: Available at http://tools.ietf.org/html/draft-zyp-json-schema-04.
®
[i.2] IETF draft-fge-json-schema-validation-00: "JSON Schema: interactive and non interactive
validation".
NOTE: Available at http://tools.ietf.org/html/draft-zyp-json-schema-04.
ETSI

---------------------- Page: 8 ----------------------

SIST ES 201 873-11 V4.7.1:2017
 7 ETSI ES 201 873-11 V4.7.1 (2017-06)
®
[i.3] World Wide Web Consortium W3C Recommendation: "XML Schema Part 1: Structures".
NOTE: Available at http://www.w3.org/TR/xmlschema11-1.
®
[i.4] World Wide Web Consortium W3C Recommendation: "XML Schema Part 2: Datatypes".
NOTE: Available at http://www.w3.org/TR/xmlschema11-2.
[i.5] 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.6] 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.7] 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.8] 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.9] 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.10] 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.11] 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.12] ETSI ES 202 789: "Methods for Testing and Specification (MTS); The Testing and Test Control
Notation version 3; TTCN-3 Language Extensions: Extended TRI".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in ETSI ES 201 873-1 [1] apply.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ASN.1 Abstract Syntax Notation no. 1
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: 9 ----------------------

SIST ES 201 873-11 V4.7.1:2017
 8 ETSI ES 201 873-11 V4.7.1 (2017-06)
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.3] and [i.4]).
NOTE: Though an IETF draft proposal exists for JSON schema (see [i.1] and [i.2]), 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.5], or XSD [i.6] as shown in figure 1, while other documents as ETSI
ES 202 781 [i.7], ETSI ES 202 782 [i.8], ETSI ES 202 784 [i.9], ETSI ES 202 785 [i.10], ETSI ES 202 786 [i.11] and
ETSI ES 202 789 [i.12] specify language extensions and thus can define additional rules to the JSON/TTCN-3 mapping
defined in the present document.




JSON Types


& Values

Other

presentation
TTCN-3
formats as
Other Types
Core
defined in
& Values
2
TTCN-3 User
Language
other parts of
the standard
or user-
specific
formats
Other Types Note: The shaded boxes are
& Values
n not defined in this document

Figure 1: User's view of the core language and the various presentation formats
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].
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.
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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);
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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 ANSI/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 instru
...