uk.ac.sheffield.vtts.model

Class Service

java.lang.Object

uk.ac.sheffield.vtts.model.Element

uk.ac.sheffield.vtts.model.Named

uk.ac.sheffield.vtts.model.Annotated

uk.ac.sheffield.vtts.model.Specification

uk.ac.sheffield.vtts.model.Service

public class Service
extends Specification

Service represents a a model or specification of a software service. The model consists of two parts, a Protocol, describing the Memory and Operations of the Service, and a Machine, describing the States and Transitions of the Service. Both aspects are used to simulate the behaviour of the Service.

Version:

Broker@Cloud 1.0

Author:

Anthony J H Simons

Field Summary

Fields

Modifier and Type	Field and Description
static int	TIMEOUT The timeout for state-space searches, set to five seconds.

Fields inherited from class uk.ac.sheffield.vtts.model.Specification

multiTest, testDepth

Fields inherited from class uk.ac.sheffield.vtts.model.Annotated

notice

Fields inherited from class uk.ac.sheffield.vtts.model.Named

name

Constructor Summary

Constructors

Constructor and Description
Service() Creates a default Service with no name.
Service(java.lang.String name) Creates a named Service.

Method Summary

Methods

Modifier and Type	Method and Description
Service	addMachine(Machine machine) Adds the finite state Machine of this Service.
Service	addProtocol(Protocol protocol) Adds the Protocol to this service.
protected void	analyseCoverage(Notice topInfo) Checks whether all the States and Transitions were covered by the generated TestSuite and adds suitable Warning nodes if any States, or Transitions, were not covered by the TestSuite.
TestSuite	generateTests() Generates the TestSuite for this Service, using generation parameters from this Service.
TestSuite	generateTests(int testDepth, boolean multiTest) Generates the TestSuite for this Service, using the given generation parameters.
protected TestSequence	generateTestSequence(Sequence sequence) Generates a single TestSequence from an abstract Sequence of Events.
protected TestStep	generateTestStep(Event event) Generates a single TestStep from an abstract Event.
protected TestSuite	generateTestSuite(Language language) Generates the TestSuite for this Service, by simulating the Service using a bounded Language.
Machine	getMachine() Returns the finite state Machine of this Service.
Protocol	getProtocol() Returns the Protocol of this service.
protected Language	getStateCover(Alphabet alphabet) Calculates the state cover for this Service.
Machine	validateMachine() Validates the states and transitions of this Service's state Machine.
Protocol	verifyProtocol() Verifies this Service's Protocol for consistency and completeness.

Methods inherited from class uk.ac.sheffield.vtts.model.Specification

getMultiTest, getName, getTestDepth, isMultiTest, setMultiTest, setTestDepth

Methods inherited from class uk.ac.sheffield.vtts.model.Annotated

addNotice, getNotice

Methods inherited from class uk.ac.sheffield.vtts.model.Named

equals, hashCode, setName, setName, toString

Methods inherited from class uk.ac.sheffield.vtts.model.Element

safeEquals, safeHashCode, semanticError

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

TIMEOUT

public static final int TIMEOUT

The timeout for state-space searches, set to five seconds.

See Also:

Constant Field Values

Constructor Detail

Service

public Service()

Creates a default Service with no name.

Service

public Service(java.lang.String name)

Creates a named Service. The name is supplied in "CapitalCase", and should correspond to the type name of the unit representing the whole service. In a Java grounding, this would be the name of the class or interface under test.

Parameters:

name - the name of this Service.

Method Detail

addProtocol

public Service addProtocol(Protocol protocol)

Adds the Protocol to this service. The Protocol describes the global Memory and set of Operations for the Service. It describes the detailed abstract behaviour of each Operation, in terms of its Inputs, Outputs, Failures and alternative Scenarios. Ensures that the Protocol is named consistently with this Service.

Parameters:

protocol - the Protocol to add.

Returns:

this Service.

getProtocol

public Protocol getProtocol()

Returns the Protocol of this service. The Protocol describes the global Memory and set of Operations for the Service. It describes the detailed abstract behaviour of each Operation, in terms of its Inputs, Outputs, Failures and alternative Scenarios.

Returns:

the Protocol of this service.

addMachine

public Service addMachine(Machine machine)

Adds the finite state Machine of this Service. The Machine models the state transition diagram for the Service. In particular, it models modes in which particular Operations are available, or unavailable. Ensures that the Machine is named consistently with this Service.

Parameters:

machine - the finite state Machine to add.

Returns:

this Service.

getMachine

public Machine getMachine()

Returns the finite state Machine of this Service. The Machine models the state transition diagram for the Service. In particular, it models modes in which particular Operations are available, or unavailable.

Returns:

the finite state Machine of this Service.

validateMachine

public Machine validateMachine()

Validates the states and transitions of this Service's state Machine. Checks for correspondence between the Transitions in the Machine and the Scenarios in the Protocol. Checks for the existence of an initial state and that all states are reachable in the Machine (notwithstanding any guards in the Protocol). Checks the completeness of each State under all Events from the Alphabet. Annotates the Machine with various Notice, Analysis and Warning nodes.

Returns:

the annotated Machine.

verifyProtocol

public Protocol verifyProtocol()

Verifies this Service's Protocol for consistency and completeness. Checks for correspondence between the Scenarios in the Protocol and the Transitions in the Machine. Checks that the Memory is correctly initialised. Checks that each Operation is deterministic and complete under all input and memory conditions. Annotates the Protocol with various Notice, Analysis and Warning nodes.

Returns:

the annotated Protocol.

generateTests

public TestSuite generateTests()

Generates the TestSuite for this Service, using generation parameters from this Service. Generates a high-level TestSuite by simulating the complete Service specification, which is a Stream X-Machine. Explores all Transition paths from every State of the Machine, up to a maximum bounded depth, then filters these paths through the guard Conditions of the Operations in the Protocol. Generates positive tests for paths accepted by both the Machine and the Protocol; and negative tests for paths accepted by the Protocol, but rejected by the Machine. Prunes infeasible paths rejected by the Protocol. Prunes redundant paths with ignored steps in the path prefix. Optionally compresses the resulting TestSuite if multi-objective tests were requested.

Returns:

an optimised TestSuite.

generateTests

public TestSuite generateTests(int testDepth,
                      boolean multiTest)

Generates the TestSuite for this Service, using the given generation parameters. Generates a high-level TestSuite by simulating the complete Service specification, which is a Stream X-Machine. Explores all Transition paths from every State of the Machine, up to a maximum bounded depth, then filters these paths through the guard Conditions of the Operations in the Protocol. Generates positive tests for paths accepted by both the Machine and the Protocol; and negative tests for paths accepted by the Protocol, but rejected by the Machine. Prunes infeasible paths rejected by the Protocol. Prunes redundant paths with ignored steps in the path prefix. Optionally compresses the resulting TestSuite if multi-objective tests were requested.

Parameters:

testDepth - the maximum depth of generated test paths.

multiTest - whether to generate multi-objective tests.

Returns:

an optimised TestSuite.

getStateCover

protected Language getStateCover(Alphabet alphabet)

Calculates the state cover for this Service. This is the smallest Language containing the shortest Sequences that will reach every State in this Service's Machine, via Transitions whose guard conditions are also satisfied in this Service's Protocol. Performs a breadth-first search, starting with the empty Sequence, and extending this on each iteration with every Event from the Alphabet, until every State has been visited once. Times out if the search eventually fails to reach every State.

Parameters:

alphabet - the Alphabet for this Service's Machine.

Returns:

the state cover Language for this Service.

generateTestSuite

protected TestSuite generateTestSuite(Language language)

Generates the TestSuite for this Service, by simulating the Service using a bounded Language. Presents the Language to the Machine and Protocol to see whether each Sequence is accepted or rejected. A Sequence that is accepted by both the Machine and the Protocol yields a positive test case; a Sequence accepted by the Protocol and rejected by the Machine yields a negative test case; a Sequence rejected by the Protocol is infeasible under the memory and input conditions, so is pruned; and a Sequence containing ignored steps in the prefix is redundant, so is pruned. If multi-objective tests were requested, merges shorter tests with longer tests of which they are the prefix.

Parameters:

language - the Language used to simulate this Service.

Returns:

the TestSuite specified by the generation parameters.

generateTestSequence

protected TestSequence generateTestSequence(Sequence sequence)

Generates a single TestSequence from an abstract Sequence of Events. If the abstract Sequence is accepted by the Protocol and the Machine, generates a positive case. If the Sequence is accepted by the Protocol but refused by the Machine, generates a negative case. If the Sequence is refused by the Protocol, it is infeasible and so no TestSequence can be generated. This is valid, since any complementary Sequence accepted by the Protocol will also constitute a successful negative test of the infeasible Sequence. TestSequences are truncated after the first refusal, to avoid generating TestSequences with nullops in the prefix.

Parameters:

sequence - the Sequence of Events.

Returns:

a TestSequence, or null.

generateTestStep

protected TestStep generateTestStep(Event event)

Generates a single TestStep from an abstract Event. If the Event is accepted both by the Protocol and the Machine, fires the event and creates a positive TestStep (to be accepted). If the Event is only accepted by the Protocol, but refused by the Machine, generates a negative TestStep (to be ignored). If the Protocol refuses the Event, it is infeasible given the current memory and inputs, so no TestStep is created. The TestStep is labelled with the reached State (after firing) or the unchanged State (after refusal).

Parameters:

event - the Event.

Returns:

a TestStep, or null.

analyseCoverage

protected void analyseCoverage(Notice topInfo)

Checks whether all the States and Transitions were covered by the generated TestSuite and adds suitable Warning nodes if any States, or Transitions, were not covered by the TestSuite.

Parameters:

topInfo - the top-level Notice.