ETSI TS 103 597-1 V1.1.1 (2021-01)

Methods for Testing and Specification (MTS); Test Specification for MQTT; Part 1: Conformance Tests

DTS/MTS-TSTMQTT-1

General Information

• Status: Not Published
• Technical Committee: MTS TST - Testing
• Current Stage: 12 - Completion
• Due Date: 05-Jan-2021
• Completion Date: 11-Jan-2021

Standards Content (Sample)

ETSI TS 103 597-1 V1.1.1 (2021-01)






TECHNICAL SPECIFICATION
Methods for Testing and Specification (MTS);
Test Specification for MQTT;
Part 1: Conformance Tests

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2 ETSI TS 103 597-1 V1.1.1 (2021-01)



Reference
DTS/MTS-TSTMQTT-1
Keywords
conformance, TSS&TP
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3 ETSI TS 103 597-1 V1.1.1 (2021-01)
Contents
Intellectual Property Rights . 4
Foreword . 4
Modal verbs terminology . 4
Introduction . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 5
3 Definition of terms, symbols and abbreviations . 5
3.1 Terms . 5
3.2 Symbols . 6
3.3 Abbreviations . 6
4 Test Suite Structure . 6
4.0 Introduction . 6
4.1 Broker as SUT . 6
4.2 Client as SUT . 8
4.3 TP naming convention . 9
4.4 TP structure . 9
5 Test Purposes for MQTT Broker . 10
6 Test Purposes for MQTT Client . 72
Annex A (normative): MQTT Test Purposes (TPs) . 89
A.0 Introduction . 89
History . 90


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4 ETSI TS 103 597-1 V1.1.1 (2021-01)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Methods for Testing and
Specification (MTS).
The present document is part 1 of a multi-part deliverable covering the MQTT protocol as identified below:
Part 1: "Conformance Tests";
Part 2: "Security Tests";
Part 3: "Performance Tests".
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.
Introduction
While the Internet of Things (IoT) is on the rise, the quality assurance of interconnected systems becomes an
ever-increasing challenge. Within the last years, many different IoT protocols came to the fore. The MQ Telemetry
Transport (MQTT) protocol is one of the most popular representatives as many surveys have shown.
Although many implementations for the MQTT protocol exist, it lacks in satisfying quality assurance. While many IoT
components communicate over standardized protocols, communication protocols for IoT like MQTT or CoAP evolved
over time without a holistic approach for quality assurance.
In the present document the conformance testing is presented. It provides a basis for interoperability testing and
performance testing. The latter is presented in ETSI TS 103 597-3 [i.3].

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5 ETSI TS 103 597-1 V1.1.1 (2021-01)
1 Scope
The present document provides a test specification, i.e. an overall test suite structure and catalogue of test purposes for
the MQ Telemetry Transport (MQTT). It will be a reference base for both client-side test campaigns and server-side test
campaigns addressing the conformance issues.
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] OASIS Standard: "MQTT Version 3.1.1".
[2] ETSI ES 203 119-4: "Methods for Testing and Specification (MTS); The Test Description
Language (TDL); Part 4: Structured Test Objective Specification (Extension)".
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] ISO/IEC 9646-1: " Information technology -- Open Systems Interconnection -- Conformance
testing methodology and framework -- Part 1: General concepts".
[i.2] ETSI ES 202 951: "Methods for Testing and Specification (MTS); Model-Based Testing (MBT);
Requirements for Modelling Notations".
[i.3] ETSI TS 103 597-3: "Methods for Testing and Specification (MTS); Test Specification for
MQTT; Part 3: Performance Tests".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
conformance: extent to which an implementation of a standard satisfies the requirements expressed in that standard
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6 ETSI TS 103 597-1 V1.1.1 (2021-01)
conformance testing: process to verify to what extent the IUT conforms to the standard
Implementation Under Test (IUT): implementation of one or more Open Systems Interconnection (OSI) protocols in
an adjacent user/provider relationship, being the part of a real open system, which is to be studied by testing
(ISO/IEC 9646-1 [i.1])
system under test: real open system in which the implementation under test resides (ETSI ES 202 951 [i.2])
test purpose: non-formal high-level description of a test, mainly using text
test suite structure: document defining (hierarchical) grouping of test cases according to some rules
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
IUT Implementation Under Test
MQTT MQ Telemetry Transport
SUT System Under Test
TDL Test Description Language
TDL-TO Test Description Language - Test Objectives
TSS Test Suite Structure
4 Test Suite Structure
4.0 Introduction
In the first one an MQTT server as SUT is considered and in the latter, an MQTT client as SUT is considered
The structure itself is partly derived from the MQTT specification [1] but changed due to overlapping functions that
cannot be tested separately.
4.1 Broker as SUT
1) All mandatory message data fields
a) CONNECT Control Packet
i) Fixed Header
1) Header Flags
ii) Variable Header
1) Protocol Name
2) Protocol Level
3) Reserved Flags
4) Last Will Testament Flags
5) Credentials Flags
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7 ETSI TS 103 597-1 V1.1.1 (2021-01)
iii) Payload
1) Client Identifier
2) Will Topic
3) Credentials
b) CONNACK Control Packet
i) Fixed Header
ii) Variable Header
1) Clean Session
2) Present Session
3) Return Codes
c) SUBSCRIBE Control Packet
i) Fixed Header
1) Header Flags
ii) Variable Header
1) Packet Identifier
iii) Payload
1) UTF-8 Encoding
2) Topic Filter
3) Requested QoS
d) SUBACK Control Packet
i) Fixed Header
1) Header Flags
ii) Variable Header
1) Packet Identifier
iii) Payload
1) Return Codes
e) UNSUBSCRIBE Control Packet
i) Fixed Header
1) Header Flags
ii) Variable Header
1) Packet Identifier
iii) Payload
1) UTF-8 Encoding
2) Topic Filters
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8 ETSI TS 103 597-1 V1.1.1 (2021-01)
f) UNSUBACK Control Packet
i) Fixed Header
ii) Variable Header
g) PINGREQ Control Packet
i) Fixed Header
h) PINGRESP Control Packet
i) Fixed Header
i) DISCONNECT Control Packet
i) Fixed Header
2) Protocol features
a) General
i) QoS levels
ii) Delivery retransmission
iii) Retained messages
iv) Message ordering
v) Anonymous client identifier
b) Connect/disconnect (session handling)
i) Credentials
ii) Session initiation
iii) Session states
c) Subscribe
d) Unsubscribe
e) Immediate publish (w/o awaiting for CONNACK)
f) Last Will and Testament message
g) Heartbeats: keepAlive values
h) Topic names/filters
i) Error handling
4.2 Client as SUT
1) All mandatory message data fields
a) CONNECT Control Packet
b) CONNACK Control Packet
c) PUBLISH Control Packet
d) PUBACK Control Packet
e) PUBREC Control Packet
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9 ETSI TS 103 597-1 V1.1.1 (2021-01)
f) UNSUBACK Control Packet
g) PUBREL Control Packet
h) PUBCOMP Control Packet
i) SUBSCRIBE Control Packet
j) UNSUBSCRIBE Control Packet
k) DISCONNECT Control Packet
2) Protocol features
a) keepAlive values
4.3 TP naming convention
TPs are numbered, starting at 001, within each main scope. The main scopes are organized according to the TSS. Some
TPs may not have a second level scope.
Table 1: TP identifier naming convention scheme
Identifier: TP____<2nd_lvl_scope>*_*

TP = Test Purpose Fixed to TP
= Protocol name Fixed to MQTT
= Type of IUT Client or Broker
= Main scope Scope of the protocol (feature)
Name of the scoped Control Packet
FEAT     Protocol Features
<2nd_lvl_scope> = Second level scope RTND     Retained Messages
= Sequential number From 001 to 999

*optional

4.4 TP structure
Each TP has been written in TDL-TO and thus in a structured manner which is consistent with all other TPs. The
intention of this is to make the TPs more formal. In addition, a more readable format is provided by generating tables
out of the TDL-TO format. The defined structure, that has been used, is illustrated in table 2. This table should be read
in conjunction with any TP, i.e. please use a TP as an example to facilitate the full comprehension of table 2. All
structures are defined formally in the TDL Specification ETSI ES 203 119-4 [2].
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10 ETSI TS 103 597-1 V1.1.1 (2021-01)
Table 2: Structure of a single TP
TP part Text Example
Header
 see table 1
 "The IUT has to close network connect …"
[MQTT-3.2.2-6]
PIC_BROKER_BASIC
Initial … the IUT entity having a present session for the
Free text description of the condition that the IUT
condition has reached before the test purpose applies. CLIENT_ID entity …
(optional)
Start point Describes the full logic of the test purpose. Expected behavior
Includes trigger and expected behavior of the ensure that { … }
IUT.
Trigger
One or more actions that trigger an expected when {
response of the IUT. Mostly a set of different  the IUT entity receives a CONNECT message
messages the IUT receives.  containing header_flags indicating value
 '1111'B;
}
Expected Describes the response that the IUT sends after then {
behavior receiving a certain (set of) messages. This  the IUT entity closes the TCP_CONNECTION
response describes the pass criteria }

5 Test Purposes for MQTT Broker
TP Id
TP_MQTT_BROKER_CONNECT_001
Test Objective Verify that the IUT closes the network connection if fixed header flags in CONNECT Control
Packet are invalid.
Reference
[MQTT-2.2.2-1], [MQTT-2.2.2-2], [MQTT-3.1.4-1], [MQTT-3.2.2-6]
PICS Selection PICS_BROKER_BASIC
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
     header_flags indicating value '1111'B;
  }
  then {
      the IUT closes the TCP_CONNECTION
  }
}
Final Conditions


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11 ETSI TS 103 597-1 V1.1.1 (2021-01)
TP Id TP_MQTT_BROKER_CONNECT_002
Test Objective Verify that the IUT either disconnects the client or continues processing the CONNECT Control
Packet if the protocol name does not correspond to 'MQTT'.
Reference [MQTT-3.1.2-1], [MQTT-3.1.4-4]
PICS Selection PICS_BROKER_BASIC
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME_INVALID,
      protocol_level indicating value 0x04;
  }
  then {
      the IUT closes the TCP_CONNECTION
      // TODO: missing in TTCN-3 Implementation
      or the IUT sends a CONNACK message containing
      connect_return_code indicating value 0x00;
  }
}
Final Conditions


TP Id TP_MQTT_BROKER_CONNECT_003
Test Objective
Verify that the IUT responds to supported protocol levels (in scope: MQTT-3.1.1) with the return
code 0x00.
Reference [MQTT-3.1.2-2], [MQTT-3.1.4-4]
PICS Selection
PICS_BROKER_BASIC
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04;
  }
  then {
      the IUT sends a CONNACK message containing
      connect_return_code indicating value 0x00;
  }
}
Final Conditions


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12 ETSI TS 103 597-1 V1.1.1 (2021-01)
TP Id TP_MQTT_BROKER_CONNECT_004
Test Objective Verify that the IUT validates the reserved flags in the CONNECT Control Packet.
Reference [MQTT-3.1.2-3], [MQTT-3.1.4-1], [MQTT-3.2.2-6]
PICS Selection PICS_BROKER_BASIC
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04,
      connect_flags containing
        reserved_field indicating value '1'B;
      ;
  }
  then {
      the IUT closes the TCP_CONNECTION
  }
}
Final Conditions


TP Id TP_MQTT_BROKER_CONNECT_005
Test Objective Verify that the IUT validates the will_topic and will_message fields if the will_flag is set to 1.
Reference [MQTT-3.1.2-9], [MQTT-3.1.4-1], [MQTT-3.2.2-6]
PICS Selection PICS_BROKER_BASIC and PICS_BROKER_LWT
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04,
      connect_flags containing
        will_flag indicating value '1'B,
        will_qos corresponding to AT_MOST_ONCE,
        will_retain indicating value '0'B,
        reserved_field indicating value '0'B;
      ,
      payload containing
        will_topic indicating value omit,
        will_message indicating value omit;
      ;
  }
  then {
      the IUT closes the TCP_CONNECTION
  }
}
Final Conditions


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13 ETSI TS 103 597-1 V1.1.1 (2021-01)
TP Id TP_MQTT_BROKER_CONNECT_006
Test Objective Verify that the IUT validates the the will_topic and will_message fields to be omitted if the will_flag
is set to 0.
Reference [MQTT-3.1.2-11], [MQTT-3.1.4-1], [MQTT-3.2.2-6]
PICS Selection PICS_BROKER_BASIC and PICS_BROKER_LWT and PICS_BROKER_RTND
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04,
      connect_flags containing
        will_flag indicating value '0'B,
        will_qos corresponding to AT_LEAST_ONCE,
        will_retain indicating value '1'B,
        reserved_field indicating value '0'B;
      ,
      payload containing
        will_topic corresponding to PX_WILL_TOPIC,
        will_message corresponding to PX_WILL_MESSAGE;
      ;
  }
  then {
      the IUT closes the TCP_CONNECTION
  }
}
Final Conditions


TP Id TP_MQTT_BROKER_CONNECT_007
Test Objective Verify that the IUT validates the will_qos field to be set to 0 if the will_flag is set to 0.
Reference [MQTT-3.1.2-13], [MQTT-3.1.4-1], [MQTT-3.2.2-6]
PICS Selection PICS_BROKER_BASIC
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04,
      connect_flags containing
        will_flag indicating value '0'B,
        will_qos corresponding to AT_LEAST_ONCE,
        will_retain indicating value '0'B,
        reserved_field indicating value '0'B;
      ;
  }
  then {
      the IUT closes the TCP_CONNECTION
  }
}
Final Conditions


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14 ETSI TS 103 597-1 V1.1.1 (2021-01)
TP Id TP_MQTT_BROKER_CONNECT_008
Test Objective Verify that the IUT validates the will_qos field and rejects connections with an invalid will_qos
value.
Reference [MQTT-3.1.2-14], [MQTT-3.1.4-1], [MQTT-3.2.2-6]
PICS Selection PICS_BROKER_BASIC and PICS_BROKER_LWT
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04,
      connect_flags containing
        will_flag indicating value '1'B,
        will_qos corresponding to INVALID_QOS,
        will_retain indicating value '0'B,
        reserved_field indicating value '0'B;
      ;
  }
  then {
      the IUT closes the TCP_CONNECTION
  }
}
Final Conditions


TP Id
TP_MQTT_BROKER_CONNECT_009
Test Objective
Verify that the IUT validates the will_qos field if the will_flag is set to 1.
Reference [MQTT-3.1.2-14], [MQTT-3.1.4-4]
PICS Selection PICS_BROKER_BASIC and PICS_BROKER_LWT
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04,
      connect_flags containing
        will_flag indicating value '1'B,
        will_qos corresponding to AT_MOST_ONCE,
        will_retain indicating value '0'B,
        reserved_field indicating value '0'B;
      ;
  }
  then {
      the IUT sends a CONNACK message containing
      connect_return_code indicating value 0x00;
  }
}
Final Conditions


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15 ETSI TS 103 597-1 V1.1.1 (2021-01)
TP Id TP_MQTT_BROKER_CONNECT_010
Test Objective Verify that the IUT validates the will_flag and will_retain flags to be set correctly.
Reference [MQTT-3.1.2-15], [MQTT-3.1.4-1], [MQTT-3.2.2-6]
PICS Selection PICS_BROKER_BASIC
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04,
      connect_flags containing
        will_flag indicating value '0'B,
        will_qos corresponding to AT_MOST_ONCE,
        will_retain indicating value '1'B,
        reserved_field indicating value '0'B;
      ,
      payload containing
        will_topic indicating value omit,
        will_message indicating value omit;
      ;
  }
  then {
      the IUT closes the TCP_CONNECTION
  }
}
Final Conditions


TP Id TP_MQTT_BROKER_CONNECT_011
Test Objective
Verify that the IUT validates the will_retain flag to be set to 0 if the will_flag is set to 0.
Reference
[MQTT-3.1.2-15], [MQTT-3.1.4-4]
PICS Selection PICS_BROKER_BASIC
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04,
      connect_flags containing
        will_flag indicating value '0'B,
        will_qos corresponding to AT_MOST_ONCE,
        will_retain indicating value '0'B,
        reserved_field indicating value '0'B;
      ,
      payload containing
        will_topic indicating value omit,
        will_message indicating value omit;
      ;
  }
  then {
      the IUT sends a CONNACK message containing
      connect_return_code indicating value 0x00;
  }
}
Final Conditions


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16 ETSI TS 103 597-1 V1.1.1 (2021-01)
TP Id TP_MQTT_BROKER_CONNECT_012
Test Objective Verify that the IUT validates the password flag to be set to 0 if the user_name_flag is set to 0.
Reference [MQTT-3.1.2-22], [MQTT-3.1.4-1], [MQTT-3.2.2-6]
PICS Selection PICS_BROKER_BASIC and PICS_BROKER_AUTH
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating value '0000'B,
      protocol_name corresponding to PROTOCOL_NAME,
      protocol_level indicating value 0x04,
      connect_flags containing
        user_name_flag indicating value '0'B,
        password_flag indicating value '1'B,
        will_flag indicating value '0'B,
        will_qos corresponding to AT_MOST_ONCE,
        will_retain indicating value '0'B,
        reserved_field indicating value '0'B;
      ;
  }
  then {
      the IUT closes the TCP_CONNECTION
  }
}
Final Conditions


TP Id TP_MQTT_BROKER_CONNECT_013
Test Objective Verify that the IUT validates the username field to be omitted if the user_name_flag is set to 0.
Reference [MQTT-3.1.2-18], [MQTT-3.1.2-22], [MQTT-3.1.4-1], [MQTT-3.2.2-6]
PICS Selection
PICS_BROKER_BASIC and PICS_BROKER_AUTH
Initial Conditions

Expected Behaviour
ensure that {
  when {
      the IUT receives a CONNECT message containing
      header_flags indicating v
...