Block 3 Glossary

Question 1

Acceptance Testing

Answer 1

The formal testing of an entire system, conducted by a customer, to determine whether it satisfies its acceptance criteria and thus whether the customer should accept the system.

Question 2

Adapeter

Answer 2

A design pattern that addresses the problem of a class having an interface different from the one the client expects.

Question 3

Adapter Pattern

Answer 3

A design pattern used when a client expects to make calls to a particular interface different from the one that is implemented.

Question 4

Analysis Pattern

Answer 4

A high-level pattern describing a solution at a conceptual analysis level problem.

Question 5

Analytical Completeness

Answer 5

A measure of completeness where only the functional requirements are considered.

Question 6

Applet

Answer 6

A small Java program that is downloaded from a server and executes in a container consisting of a Java plug-in installed in the client’s browser.

Question 7

Architectural Pattern

Answer 7

Codifies recurrent software architectures by describing the key elements of the architecture and how they fit together. It also describes the qualities of systems that are assembled following the pattern.

Question 8

Arcitectural View

Answer 8

A model of the architecture, that captures the concerns of a group of stakeholders of the system.

Question 9

Architecture Specilaisation

Answer 9

The process of specialising an architecture by selecting specific components etc.

Question 10

Architecture Specification

Answer 10

The specification of the architecture of a system. It is also the third step in the product line process, where reference architectures are produced.

Question 11

Assertion (Handling) Mechanism

Answer 11

A programming construct which, at run-time, allows an assertion to be executed, and alerts the user to an assertion violation. Also referred to as an assertion mechanism.

Question 12

Assertion Statement

Answer 12

A statement of what must be true at a particular point in the execution of a method.

Question 13

Assume

Answer 13

A condition that a component needs, to operate correctly.

Question 14

Asynchronous

Answer 14

(communication) When the sender can continue without waiting for an answer from another component.

Question 15

Basis-Path Testing

Answer 15

A white box testing technique based on the cyclomatic-complexity metric which ensures that all statements in a method are tested at least once.

Question 16

Blackboard

Answer 16

A variant of a data-centred architectural style in which the store is active and informs users of changes, so that communication may be initiated from either end.

Question 17

Black Box Testing

Answer 17

Used to test that each aspect of the customer’s requirements is handled correctly by an implementation. Black box testing ‘sees’ a system through its specification – the specification defines what the system should do and, through black box testing, we make sure it does it.

Question 18

Boundary Testing

Answer 18

A type of black box testing that focuses on producing test data at the boundaries between partitions of the input data space (also know as fence testing).

Note that the input data space is simply the set of all values that an input can take, and a partition, also known as a subdomain, is simply a set of input values that require essentially the same processing.

Question 19

Bursty Event

Answer 19

An event coming in sudden and unpredictable clusters overlaying normally low background activity.

Question 20

Callee

Answer 20

Component that receives a procedure call in a call-return architecture.

Question 21

Call-Return Style

Answer 21

An architectural style in which one component (the caller) makes a procedure call to another component (often known as the callee) and waits for the call to return.

Question 22

Case Analysis

Answer 22

When carrying boundary testing, case analysis is the process used to partition test data into subdomains, i.e. sets of input values that require similar processing.

Case analysis aids the identification of boundaries between subdomains. At these boundaries, the kind of processing required changes.

Question 23

Class Invariant

Answer 23

A constraint that must be true at all times, other than during when one of its methods is executing. A statement about the values of the attributes of a class that must hold for all instances of that class.

Question 24

Client-Server

Answer 24

An architectural style in which one component (the server) waits for requests from clients, processes each one as it as received, and returns a response to the client.

Question 25

Cloud Computing

Answer 25

A model in which software runs on remote facilities provided by a third-party supplier.

Question 26

Completeness

Answer 26

The degree to which full implementation of the required functionality has been achieved.

Question 27

CBD

Answer 27

Component-Based Development

An approach to the development of software by assembling reusable self-contained software components.

Question 28

Component Collection

Answer 28

The fourth step in the product line process where the repository of candidate componentsaccompanying the architecture is gathered together.

Question 29

Component Selection and Specialisation

Answer 29

The process of selecting appropriate components for a system and specialising them to the application domain. (See also domain.)

Question 30

Concern

Answer 30

Some aspect of the system that is of crucial importance from the point of view of one or more groups of stakeholders.

Question 31

Connector

Answer 31

An element of an architecture that establishes the communication between components.

Question 32

Consistency

Answer 32

The property of two descriptions agreeing with each other, that is, not making statements that cannot be simultaneously true.

Question 33

Container

Answer 33

An object (or component) that exists to encompass other objects and provide operations to access or iterate over its contents. In Java EE, a special run time environment that provides components with supporting services (for example, life-cycle management, security, deployment, and run-time services).

Question 34

Context Dependency

Answer 34

A service required by a module in order for it to work.

Question 35

Controller

Answer 35

In the MVC, the controller is the component that handles all user inputs which affect the model.

Question 36

CBO

Answer 36

Coupling Between Objects Metric

For a given class, CBO is defined as the number of relationships the class has with other classes. The more relationships a class has, and so the higher the value of this metric, the more difficult it is to understand the use of the given class.

Question 37

Cyclomatic-Compexity Metric

Answer 37

A measure of the complexity of a method by counting the number of independent paths through a method body.

Question 38

Data-Centred

Answer 38

Architectural style where there is a data provider which is a centralised store of persistent data.

Question 39

Data-Centred Style

Answer 39

An architectural style in which there is a centralised data provider, together with a number of clients who are data consumers. If the provider simply responds to client requests it is called a database. A variant in which the data store informs clients when a change occurs is known as a blackboard.

Question 40

Data-Flow Style

Answer 40

An architectural style in which each component (called a filter) accepts a stream of data, processes it, and passes the result on to the next filter. A filter has no knowledge of other filters upstream or downstream but simply operates on the data it is given.

Question 41

Data Loss

Answer 41

The amount of data lost because the system fails to record it.

Question 42

Defensive Programming

Answer 42

A design philosophy that says preconditions should always be checked. Each operation is responsible for making sure that it is safe to proceed. The checking is placed very close to the code that depends on it.

Question 43

Dependency Injection

Answer 43

A Java EE container service that creates and manages an EJB object ‘injecting’ the necessary references into the client.

Question 44

Deployment Model

Answer 44

A UML model describing how the components of a system are to be mapped onto different machines and how they will communicate.

Question 45

DIT

Answer 45

Depth-of-Inheritance-Tree

For a given class, this is defined as its number of ancestors. Because of inheritance, a method in the given class can be defined in any of its ancestors. DIT is, therefore, a measure of the number of classes essential to the understanding of the methods of the given class. The deeper a class is in an inheritance tree, and so the higher the value of this metric, the more difficult the class may be to understand.

Question 46

DbC

Answer 46

Design by Contract

The process of developing software based on the notion of contracts between objects, which are expressed as assertions.

Question 47

Design Pattern

Answer 47

A middle-level pattern describing a solution at a software design level.

Question 48

Developmental Testing

Answer 48

One of the four major types of software testing which checks that developmental activities have been carried out correctly, and ideally is performed by development staff and checked by quality assurance (QA) staff.

Question 49

EJB Container

Answer 49

A run-time environment where EJB components are deployed.

Question 50

Enterprise Architectures

Answer 50

Software systems designed to meet the business needs of large organisations.

Question 51

Error Guessing

Answer 51

An informal but successful black box testing technique in which the wildest test data that can be thought of is presented to the program unit.

Question 52

Executable Assertion

Answer 52

An assertion that has been coded and can be executed at run-time.

Question 53

Executable Documentation

Answer 53

Executable documentation is documentation tht allows code to be automatically checked against documention at run time. It should have no effect on program logic, and should be able to be switched on or off globally - so as not to impact performance. Not all aspects of documentation can be checked in this way, but Design by Contract and Test Driven Development are two different systematic approaches to executable documentaion.

Question 54

XP

Answer 54

Extreme Programming

An agile software development method.

Question 55

Factory

Answer 55

A specialised object for creating and initialising objects needed by clients.

Question 56

Factory Method

Answer 56

A variant of the Factory pattern particularly useful in the definition of frameworks in which application-specific factories and products can be defined based on the interfaces defined in the framework.

Question 57

Factory Pattern

Answer 57

A pattern to define a specialised object for the creation and initialisation of other objects.

Question 58

Filter

Answer 58

Element in a pipe and filter architecture that takes some data and processes it to produce a result.

Question 59

Fixture

Answer 59

The state in place and the data to be used on a test case.

Question 60

Flexibility

Answer 60

The property of a software system that indicates how easily the system can be modified.

Question 61

Foreign Key

Answer 61

In a database table, a column that holds a key from a different table.

Question 62

Framework

Answer 62

A collection of classes that together provide behaviour common to a variety of applications. The programmer creates a new application by extending and, perhaps, overriding the behaviour of the classes contained in the framework.

Also, the part of an architecture that can be reused.

Question 63

Guarantee

Answer 63

A condition that a component promises to other components.

Question 64

Heuristic Evaluation

Answer 64

User interface code should always be user tested. However, heuristic testing allows preliminary testing of interaction designs without users. Heuristic evaluation involves analysing interaction designs against recognised checklists for good practice (‘heuristics’).

Question 65

HTTP

Answer 65

Hyper Text Transer Protocol

A protocol for communication of data in the Web.

Question 66

Idiom

Answer 66

A pattern that applies within a programming language.

Question 67

Ilities

Answer 67

Quality attributes, for instance security, reliability, availability, usability etc.

Question 68

Independent Components

Answer 68

Architectural style where components execute concurrently and are decoupled as far as possible, but can communicate by messages that allow them to exchange data or coordinate their operations.

Question 69

Independent Components Style

Answer 69

An architectural style in which components are largely decoupled and execute concurrently, but coordinate with one another or exchange data by means of asynchronous messages.

Question 70

Inertial Convention

Answer 70

The assumption that state components not explicitly described as having changed in a postconditionwill remain unchanged by a method call.

Question 71

Integration and Release

Answer 71

The process of bringing items together into a unified whole, and then releasing to a customer.

Question 72

Integration Testing

Answer 72

The second stage of developmental testing in which previously tested units are tested together as an integrated whole.

Question 73

Interface

Answer 73

In general, this refers to the operations (methods), including their syntax and semantics, that a software system/subsystem/module provides to the clients of the system. In the object-oriented approach, the public operations associated with an object are referred to as its interface, or its interface operations. In Java, an interface is a construct similar to a class, which provides a specification (in the form of method headings but no implementation) of the methods for which classes implementing the interface must provide implementations.

Question 74

Interface Testing

Answer 74

Unit testing in which test data is chosen to check that the flow of information into and out from an object of the class is correct. Also a form of system testing, in the case where the systemcommunicates with other systems in the outside world, that tests its interaction with the communication system; in this context it is also referred to as protocol testing.

Question 75

Java EE

Answer 75

Java Enterprise Edition

A framework for constructing enterprise systems.

Question 76

Jitter

Answer 76

The amount of variation in latency, for example, are some responses very quick but others take much longer?

Question 77

LCOM

Answer 77

Lack-Of-Cohesion-In-Methods Metric

The number of pairs of methods that make reference to the same attributes minus the number of pairs of methods that do not; or zero should this be negative. In highly cohesive classes, methods will manipulate the same attributes.

Question 78

Latency

Answer 78

The time taken to process a stimulus, for example, how long does a search engine take to respond to a query?

Question 79

Layered Style

Answer 79

An architectural style in which the system is structured as a series of layers, each layer communicating only with the layers immediately above and below it.

Question 80

LOC

Answer 80

Lines-Of-Code Metric

A very simple measure of the complexity of a system description is given by counting the number of lines in a piece of code.

Question 81

Location Transparency

Answer 81

In a service-oriented architecture (SOA) it allows consumers to make use of the service without being aware of where the service is actually located, i.e. on which machine or even in which business organisation. The requester of the service and the service itself are only loosely bound; in particular, the requester has no knowledge of the service implementation or its platform, and they only communicate through messages. It is also possible for components to be location transparent and be invoked using a logical name rather than a physical address.

Question 82

MTTC

Answer 82

Mean Time To Change

The average of the time it takes to analyse a bug report, design an appropriate modification, implement the change, test it, and distribute the change to all users. In general, the lower the MTTC (for equivalent types of changes), the more maintainable the software product is.

Question 83

Miss Rate

Answer 83

Measures the proportion of events that are not responded to.

Question 84

Model

Answer 84

A simplification of reality, created in order to understand an aspect or viewpoint of the system being created. In the MVC, the model the component that does the processing.

Question 85

MVC

Answer 85

Model-View-Controller

Describes a high-level solution to the general problem of human–computer interaction, relating what the user sees on a screen and does with a keyboard, mouse or other interaction device, to the functions of an application and the data that it stores. The ‘model’ is the internal workings of the program, the ‘view’ is how the user sees the state of the model and the ‘controller’ is how the user changes the state or provides input. Whenever some input through a controller changes the primary data of the model, the model then informs all views and all controllers so that they in turn can update their representation of the data.

Question 86

Notification Style

Answer 86

An architectural style in which one kind of component, the observer, registers itself with another component, the subject, in order to be notified when some particular event occurs at the subject’s end.

Question 87

NOC

Answer 87

Number-Of-Children Metric

For a given class, NOC is defined as the number of children for that class. This metric is a measure of the number of classes that will be affected by changes to a given parent clas

Question 88

Observable

Answer 88

In the Observer pattern the object, also called the subject, that keeps objects registered with it informed when its state changes.

Question 89

Observer

Answer 89

In the Observer pattern objects register themselves with a Observable, in order to receive notifications when the latter’s state changes.

Question 90

Partitoning

Answer 90

This black box testing technique focuses on producing test data at the boundaries between partitions of the input data space (or input domain). Partitioning is based on the observation that common errors are often caused by a data item being just one out, or a loop being executed one too many or one too few times, for example; such errors are most visible at the boundaries of the input data space. (Also referred to as equivalence partitioning.)

Question 91

Path Parameter

Answer 91

Part of a path to be replaced by the corresponding element in the actual URI the client uses when making a request.

Question 92

Peer-To-Peer

Answer 92

An architecture where there is no clear distinction between clients and servers.

Question 93

Peer-To-Peer Style

Answer 93

An architectural style in which all components are both clients and servers and any component can request services from any other component.

Question 94

Performance

Answer 94

The ability of a system to process service requests.

Question 95

Performance Testing

Answer 95

System testing that tests that the system meets all specified operating requirements for speed, number of concurrent users permitted, etc.

Question 96

Pipe

Answer 96

Element in a pipe and filter architecture that is a conduit along which the data flows.

Question 97

Pipes and Filters

Answer 97

An architecture where filters are the elements that take some data and process it to produce a result, and pipes are the conduits along which the data flows. Also known as data-flow.

Question 98

Polymorphism

Answer 98

In object oriented programming, when a program specifies that some message is to be sent to some object, it is not always possible at compile time to determine which of several candidate methods should correspond to the message. This is because, for inheritance or other reasons, there may be several classes of object with a common interface, and the identity of the class of the receiver may not be determined till run time.

Such a message is said to be polymorphic.

Question 99

Postcondition

Answer 99

A constraint that must be true at the completion of an operation, or use case.

Question 100

Precondition

Answer 100

A constraint that must be true when an operation is invoked, or when a use case is carried out.

Question 101

Presentation Layer

Answer 101

In a layered architecture, the layer concerned with the user interface.

Question 102

Primary Key

Answer 102

In a database table, a column that uniquely identifies each row of the table.

Question 103

Product

Answer 103

In the Factory design pattern the object the factory produces.

Question 104

Product Line

Answer 104

A set of related software products for different customers, reusing major parts of the software from customer to customer, with only those parts peculiar to the particular customer being different.

Question 105

Product-Line Initiation

Answer 105

This is the first step in the product line process, where it is recognised that there is a class of commonly recurring software systems where solutions do not differ much from each other.

Question 106

Product Operation Requirements

Answer 106

How a product will be used

Question 107

Product Revision Requirements

Answer 107

How a product will be maintained.

Question 108

Product Transition Requirements

Answer 108

How a product will be modified for different operating environments.

Question 109

Profession

Answer 109

‘A form of employment, esp. one that is possible only for an educated person and after training (such as law, medicine or teaching) and that is respected in society as honourable.’ (Longman Dictionary of Contemporary English, 1987.)

Question 110

Provided Interface

Answer 110

The set of operations a component makes available to other components.

Question 111

Publisher

Answer 111

Component, in a publish-subscribe architecture, that notifies other components of updates.

Question 112

Publish-Subscribe

Answer 112

Architectural style where subscribers register to receive updates (often messages) whenever a publisher posts a new item.

Question 113

Quality Attribute Scenario

Answer 113

A tool which allows specification of non-functional requirements in a more precise and detailed form which can be used to help make architectural decisions.

Question 114

Quantity Patterns

Answer 114

A pattern which provides useful guidance on how to represent dimensioned quantities, that is, values plus their units of measurement.

Question 115

Random Testing

Answer 115

A black box testing technique in which test data is randomly generated within the input data space.

Question 116

Realisation

Answer 116

An implementation of an interface.

Question 117

Record

Answer 117

A row of a database table.

Question 118

Refactoring

Answer 118

The reorganisation of code structure for reasons such as clarity or maintainability, while making no change to the external behaviour.

Question 119

Regression Testing

Answer 119

One of the four major types of software testing, which occurs during developmental testing and system maintenance, and which checks that fixing one bug has not introduced others.

Question 120

Repository

Answer 120

Centralised store of persistent data in a data-centred architecture.

Question 121

Required Interface

Answer 121

The set of operations a component needs from other components.

Question 122

Requirements-Based Testing

Answer 122

One of the four major types of software testing which checks that a system meets the customer’s requirements, and is carried out by QA staff in conjunction with the customer.

Question 123

Requirements Pattern

Answer 123

A description of knowledge used in the elicitation of requirements.

Question 124

RFC

Answer 124

Responces-For-A-Class Metric

For a given class, RFC is defined as the size of the response set for the class. Classes with high values for this metric will be more difficult to understand than classes with low values.

Question 125

Response Set

Answer 125

All the methods of a class, including those inherited, and those it invokes.

Question 126

Restart Testing

Answer 126

System testing that tests the ability of the system to recover from errors of internal state.

Question 127

RESTful

Answer 127

A web service that uses a uniform interface consisting only of a set of standard methods which are always the same for every service.

Question 128

Reusability

Answer 128

A software quality factor affecting product transition requirements which determines the extent to which a system (or system component) can be reused in other applications, that is, how easy it is to reuse some of the software to make future developments more cost-effective.

Question 129

Security Testing

Answer 129

System testing that tests that the system does not offer opportunities to breach security.

Question 130

Self Consistency

Answer 130

System descriptions are said to be self consistent if they make no self contradictory statements.

Question 131

Service Consumer

Answer 131

Component accessing a service.

Question 132

Service Orchestration

Answer 132

Coordination of services invocation.

Question 133

SOA

Answer 133

Service-Oriented Architecture

SOA is an approach to build enterprise systems that deliver application functionality either as services to end-user applications or to build other services. In this approach, services are software assets, which are described and interact in a standard way, so that the focus of application development is the assembly of services as building blocks.

Question 134

SOCCA

Answer 134

Service-Oriented Cloud Computing Architecture

An architecture to address the integration of the principles of SOA with those of cloud computing.

Question 135

Service-Oriented Style

Answer 135

An architectural style in which set of service providers makes services available to a set of service consumers. Consumers can combine services in order to carry out business processes.

Question 136

Service Provider

Answer 136

Component implementing a service.

Question 137

Signature

Answer 137

In general, the combination of name, parameters and return type of an operation. In Java, the combination of name and formal parameters in a method heading (that is, excluding method’s return type).

Question 138

Singleton

Answer 138

A design pattern used where there should be only one instance of a class.

Question 139

Singleton Pattern

Answer 139

A pattern to ensure that a class has only one instance, and to provide a global point of access to it.

Question 140

Software Architecture

Answer 140

‘… the set of structures needed to reason about the system, which comprise software elements, relations among them, and properties of both.’ (Bass, Clements and Kazman, 2012.)

Question 141

Software Metrics

Answer 141

Measurable quantities that can be used to infer values for the software quality factors.

Question 142

SQF

Answer 142

Software Quality Factor

An attribute of a software product affected by product operation requirements, product revision requirements and product transition requirements. There are 11 such attributes: correctness, reliability, efficiency, integrity, usability, maintainability, flexibility, testability, portability, reusabilityand interoperability.

Question 143

Specific-Requirements Capture

Answer 143

Capturing the specific requirements for a new product, when using a product-line process. These are captured as specialisations and extensions of the domain model.

Question 144

Sporadic Event

Answer 144

An event that is infrequent and isolated.

Question 145

Start-Up Testing

Answer 145

System testing that tests the system’s ability to be started in a working hardware/software configuration. Following such tests, all configurations should be fully system tested individually.

Also referred to as initialisation testing.

Question 146

Statelessness

Answer 146

A property of a component when it responds to each request as a ‘one-off’, without retaining any memory of previous requests.

Question 147

Stochastic Event

Answer 147

An event that occurs randomly but according to a well-defined probability distribution: for example heads coming up when a coin is flipped.

Question 148

Straight-Through Path

Answer 148

Basis-path testing is a white box testing technique that involves choosing test data to exercise all of the paths in code.

In order to enumerate basis-path test cases, a first stp is typically to identify the straight-through path. This is the path where all loop and if conditions evaluate to false, and only default cases are selected in switch statements.

Question 149

Stress Testing

Answer 149

System testing that tests that the system can operate reliably at the limits of each of its resources (for example, to stress test a web server, we may simulate the accesses of hundreds or thousands of users all at the same time to see if it can cope with the load).

Question 150

Subdomain

Answer 150

Simply a set of input values that require essentially the same processing. Subdomains may be found by means of case analysis.

Question 151

Subscriber

Answer 151

Component, in a publish-subscribe architecture, that registers to receive updates from another component (the publisher).

Question 152

Subsitutability

Answer 152

Substitutability means that an object of one type is legitimately substitutable for an object of another type. This is allowed in Java when objects are related through inheritance (that is, an object of the child class may be substituted for an object of the parent class). However, substitutability is only sensible when the objects are related as subtype to supertype (that is, when the inheritance is inheritance for specialisation and not inheritance for construction).

Question 153

System Testing

Answer 153

The third stage of developmental testing in which the completed system is tested against the customer’s requirements.

Question 154

Tactic

Answer 154

A reusable solution to the problem of achieving particular qualities.

Question 155

Test Case

Answer 155

The set of conditions and data used to determine whether a system is working as intended.

Question 156

Test-Driven Development

Answer 156

Test driven development demands that, before any code is written, tests should be written for that code to meet. Just enough code should be written to pass those tests, and the further tests should be written and so on. On each iteration, all the tests should be run. Test driven development eases the business of making late changes to code, because the accumulated tests provide assurance that changes have not broken the code.

Question 157

Throughput

Answer 157

The number of events dealt with in a given time.

Question 158

To Do List

Answer 158

In Test-driven development, when coding anything that turns out to need more than two or three TDD cycles, it can be useful to maintain a short to do list that can feed into the first steps of future cycles. This list should be kept short.

Question 159

Unit Testing

Answer 159

The first stage of developmental testing in which units of functionality (for example, the classes in an object-oriented system) are tested in isolation.

Question 160

Usability Testing

Answer 160

One of the four major types of software testing in which the functionality and user interface are tested to ensure that they are fit for the intended users. This generally involves selected users undertaking carefully designed tasks so that measures of usability can be calculated and fed back into the development process.

Question 161

User-Command Testing

Answer 161

System testing that tests all user commands from the point of view of tolerance to syntax errors and data input errors. Also referred to as operator testing.

Question 162

User-Defined Type

Answer 162

A data type defined by the programmer using predefined types provided by the programming language.

Question 163

Validation

Answer 163

The process of checking that a software system is consistent with the customer’s requirements; that is, the developer is building the ‘right’ product. (See also verification.)

Question 164

Verification

Answer 164

A process of ensuring that the design of a system corresponds to its specification, and that the system is correctly coded according to its design; that is, all the different system descriptions are consistent and complete with respect to each other. If validation is about building the ‘right’ product, then verification is about the product being built ‘right’.

Question 165

View

Answer 165

In the MVC, the view is the representation of the model in the user interface: it displays the output from the system and is what the user perceives of the model’s state.

Question 166

Viewpoint

Answer 166

A perspective on a system from the point of view of a particular person or group of people.

Question 167

WMPC

Answer 167

Weighted-Methods-Per-Class Metric

A measure of the complexity of behaviour of a given class. It is defined as the sum of the cyclomatic complexities of each method of the class. The relationship between this metric and complexity is that a class with many simple methods may be as difficult to understand as a class with a few complicated methods.

Question 168

White Box Testing

Answer 168

Used to check that the details of an implementation are correct. White box testing ignores the ‘big picture’ of the requirements, and instead looks to detailed designs to check that the system does what it is supposed to do, correctly.