powerpoint-präsentation 4:3 englisch€¦ · test architecture components (3/6) translator...

Assuring Standard Conformance of Partial Interfaces

Hardi Hungar

> Conformance of Partial Interfaces > Hardi Hungar > 06 March 2013 DLR.de • Chart 1

Tasks for Compatibility Assurance


Interlocking – Interlocking (SCI-ILS)

Interlocking – Radio Block Center (SCI-RBC)

Interlocking – Level Crossing (SCI-LX)

Field elements (signals, point machines, train detection systems)

Thales SIEMENS

All examples taken

from the SCI-ILS

specification and test

specification

Functional Specification


• Text-based

• Distributed

• Incomplete

Technical Protocol Specification (Byte-Level)


Detailed telegram definition

Specification Objects


RaS

TA

RT

P

RTP: Rail Technics Protocol RaSTA: Rail Safe Transport Application

Target interface

External interfaces

Functional Specification Evolution: Formalisation


1. Textual functional specification

Formal protocol telegrams

2. Formalized interface specification of main

components

1. Interlocking

2. Radio Block Center

3. Level Crossing

3. …

101. Fully formal (functional) specification

Establishing

formality in a

modular way

Specification Objects


RaS

TA

RT

P

RTP: Rail Technics Protocol RaSTA: Rail Safe Transport Application

Target interface

External interfaces

Test Object: Interface Specification View


RaS

TA

RT

P

Interface Specification

Internal Interface (virtual)

Test Object: Testing View


RaS

TA

RT

P

Accessible Interfaces

Estimated time

of completing

specifications

of external

interfaces

(interlocking):

2015 (optimistic)

2017 (positive)

20nm (realistic)

(n<3)

Estimated time

of completing a

full functional

specification

(interlocking):

20??

Interface Specification - Semantically


RaSTA

BTP

Target

interface

Internal Interface (virtual)

Specification Abstraction

External interfaces

Approach: Test Architecture


RaS

TA

BT

P

Test Execution

Kernel

Translator

BTP-

RaSTA

Translator

internal-

external

Test Sequences

Test Report

Test

Cases

Links

Test Rack

Test Environment

manual

Similar to Subset 076

Test Architecture: Responsibilities


RaS

TA

BT

P

Test Execution

Kernel

Translator

BTP-

RaSTA

Translator

internal-

external

Test Sequences

Test Report

Test

Cases

Links

Test Rack

Test Environment

manual

Test Lab

Manufacturer

Test Architecture: Target Switch


RaS

TA

BT

P

Test Execution

Kernel

Translator

BTP-

RaSTA

Translator

internal-

external

Test Sequences

Test Report

Test

Cases

Links

Test Rack

Test Environment

manual

Components to

be modified on

target switch

Test Architecture Components (1/6)

Test Execution Kernel


• Interprets test sequences

• Drives and observes test object

• Generates test report

Test

Execution

Kernel


Translator BTP-RaSTA


• Simple component

• Translates between byte telegrams and physical

communication (ethernet based)

• Might involve timing imprecision

• Level of atomicity

• Message sequence

Translator

BTP-

RaSTA


Translator internal-external


• Translates between the virtual internal interface

and an external view of the system

• Might use test interfaces the manufacturer uses for

development purposes

• Might involve

• Incompleteness (not everything observable)

• Timing imprecision (delays)

• Might weaken test result

Translator

internal-

external


Translator internal-external


Implementation Option

(24/7 test rack might be expensive to build)

Translator

internal-

external


Test Report


• Details and summary of test result Test

Report

passed

passed (tolerable abviation)

? unclear

failed

not executed

Test case/sequence result

Numerical /

timing

In performing test

campaigns you

learn how to

interpret test

results. Only in an

ideal setting, there

is always a

definitive answer.

Test Architecture Components (5+6/6)

Test Cases and Sequences


• … first some facts on the test object

Test Case

Test

Sequences

Test Case – Sequence Diagram (Informal)


State Diagram


„Coloured“ State

„Uncoloured“ State

Transition

Test Object - Semantically


si {v}i

sk {v}k

sj {v}j

Fnctl

Fnctm Fnctn

si Discrete state (stable, „coloured“)

{v}i Variable valuation

Fnctl Transition sequence (realising a function)

Function :

• Enabled in each start configuration

• Terminates in one of the end configuartions si {v}i sk {v}k

Fnctl

…

S/V/Fnct-Automaton

„Coloured“ State

Transition Sequence

Variable

valuation

Translates to

test case

Genericity


• One instance of the state machine logic for each connecting track

• ESTW-ZEe: „own“ interlocking

• ESTW-ZEn: neighbouring interlocking

One (of three) main „application variants“:

One track and its different views (properties)

Interlocking may send a train out

on the track (operator indication)

Typical Track Layouts (for Testing)


Track Elements

Track Elements


Test Cases


Test Case

• Track layout:

• Precondition

• Both interlockings in some specific states

• Transition sequence

• Possibly: exit conditions

• Postcondition


Test Sequences


Test

Sequences

• Sequence of test cases

• Need full interconnection track layout

• Mapping test cases to specific tracks

• „application variant“ to „real track“

• Needs instanitation mechanism

• Currently manual process

• Robust sequence

• Emergency repair sequence when test case

fails

• Do not want to restart system too often

Testcase Formalisation (Excel Syntax)


• One example of an external representation format

Concept Evaluation


1. Observation Gap

1. ?: external ↔ internal

2. !: Manufacturer responsibility

2. Interface Interrelation Gap

1. !?: ∑ interfaces ≠ full system

2. ?: Specification evolution

3. Genericity Coverage

1. ?: Formal mapping tracks to full layouts

2. ?: All cases covered

4. Specification Coverage

1. !?: Currently: Transition coverage (arrows ≈ program branches)

2. ?: Coverage of compound transitions

3. ?: Feature interaction

powerpoint-präsentation 4:3 englisch€¦ · test architecture components (3/6) translator...

Documents