Proceedings of the International Conference on C-24

Electrical Engineering and Informatics

Institut Teknologi Bandung, Indonesia June 17-19, 2007

Automatic Generation of Test Cases from Use-Case Diagram

Noraida Ismail 1*, Rosziati Ibrahim2, Noraini Ibrahim1
1
Faculty of Information Technology and Multimedia,
2
Research Management and Innovation Center (RMIC)
University of Technology Tun Hussein Onn Malaysia (UTHM).
Parit Raja, Batu Pahat, Johor, Malaysia.

Intelligent searching techniques have been developed in order to provide a solution to the issue of finding
information relevant to the user needs, and the problem of information overload - when far too much information is
returned from a search. We employ this technique to introduce an automatic tool which used to generate the test cases
automatically according to the system’s requirement. The tool uses two steps for generating test cases. First, the system’s
requirements are transformed into a Unified Modeling Language (UML) Use-case Diagram. Second, the test cases will be
automatic generated according to the use cases respectively. In the workspace, the ToolBox is used in order to ease the
drawing of the use-case diagram. As well as allowing a user to layout the requirements of the system via a use-case
diagram in the provided workspace, a user also may type-in the properties for each of the use cases used. Once the use-
case diagram has been finalized, it can be save for further used and modification. The engine of the tool will take the use
cases from the use-case diagram and search the query string (keyword) used in the tool’s library. The searching engine
uses both search keyword and additional information of the use-case diagram. This combination will result in improving
data retrieval performance. Once the use case used matches the keyword inside the tool’s library, the engine will
automatically generate its respective test cases according to its use case.

Keywords: Intelligent Searching Engine, Artificial Intelligence, Information Retrieval, Automatic Generator, Use-Case
Diagram

1. Introduction This paper discusses on idea where this crucial part

Intelligent search technique has been proposed in of SDLC is allowed to be done at early stages and proposes
order to soft the issue of information overload – when too an automatic testing tool to validate either the system fulfills
much information is returned from a search (10). On the its requirements or not. This paper is organized as follows:
other hand, it is also help to provide a solution for reducing several introductory related works are described in Section
gap between what people really want to find, and the actual 2. Section 3 discusses the system’s requirements. An idea on
query strings they specify. This issue occurs because of same how to convert the use cases into test cases also will be
terms may have different meanings in different places. In given in Section 3. Section 4 discusses our tool in details, in
order to overcome both problems, the information retrieval particular on how to retrieve data from the database using
engine should intelligent enough to understand the user the engine of the tool. In Section 5, we summarize our work
needs. The combination of query string specified and and suggest future work.
additional information will help the information retrieval
engine to make a judgment for returning the likely relevance 2. Related Work
search result (7). There are several discussions on how using use
cases may help testing process to be done early in the
Therefore, we employ this technique into our tool, development lifecycle. Jacobson et al. (4) explained tests can
automatic generation of test cases from use case. This tool is be derived from use cases in three types: First, tests of the
used to generate the test cases automatically according to the expected flow of event; second, tests of unusual flow of
system’s use cases. These test cases are important to be used events; and third, test of any requirements attached to a use
in analyzing and validating the requirements of the system. case. Unfortunately, Jacobson et al. (4) did not discuss on
As an indispensable aspect in software development how to choose test cases and how to know when you are
practices, software testing is important to reveal errors in the done.
software and to ensure that software fulfills its requirements.
In the traditional practices of software development lifecycle Binder (8), Heumann (6) and Wood et al. (3) derive
(SDLC), testing software is done at the later stage (analysis test cases directly from requirements in natural language.
– design – prototyping – testing). From the empirical studies, Wood et al. (3) state that the most integral part of use case
delaying the software testing at later stage again will for generating test cases is the Event Flow (basic flow and
maximize the number of errors and make the process of alternate flow). The next step is creating the scenario based
fixing errors become complex, and this phenomenon will on the Event Flow before it can be used to generate the test
increase the budget of software development. cases.

However, automating the testing operation can

* Noraida Binti Ismail; anoraida@yahoo.com reduce the cost and improve the reliability and effectiveness
of software testing. Gutierez et al. (5) and Nebut et al. (2)

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Proceedings of the International Conference on C-24
Electrical Engineering and Informatics
Institut Teknologi Bandung, Indonesia June 17-19, 2007

have showed how testing operation can be automated. Nebut

et al. (2) study an approach for automating the generation of
system test scenarios from use cases in the context of object
oriented embedded software and taking into account
traceability problems between high-level views and concrete
test case execution.

In this paper, we are going to use use-case diagrams

to automatically generate test cases. These test cases will
become a checked list for software engineers in order to
validate the system’s requirement at the early software
development stages.

3. The System’s Requirements

In UML specification, requirements analysis and
design are usually done using diagrams (1). One particular Figure 1: A Use-Case Diagram for an online bookstore
diagram (a use-case diagram) is used to specify requirements system.
of the system. In a use-case diagram, two important factors
are used to describe the requirements of a system. They are Figure 1 shows a simple use-case diagram for a
actors and use cases. Actors are external entities that interact online bookstore system where only a registered user
with the system and use cases are the behaviour (or the (customer) is allowed to place an order for available items
functionalities) of a system (9) The use cases are used to on this web. These registered users are also able to cancel
define the requirements of the system. These use cases the order that they make at the previous session. On the other
represent the functionalities of the system. Most often, each hand, they may also check their order’s status.
use case is then converted into a function representing the
task of the system. Most often, use cases represent the functional
requirements of a system. If the requirements are gathered
Therefore, we can convert from each of the use case correctly, then a good use-case diagram can be formed. In
into one test case or many test cases. The relationship of the UML, sequence diagrams are usually used to manually
conversion is either one to one or one to many. However, if record the behaviour of a system by viewing the interaction
we have many use cases, then we will have many test cases. between the system and its environment (5). These sequence
Therefore, an automatic tool would be more wisely used in diagrams describe in details activities for use cases.
order to generate test cases from use cases of any system. Therefore, the sequence diagrams can be used to help in
generating the correct test cases. Based on Figure 1, a use-
In most cases, use cases are developed based on the case diagram can be used to generate test cases of that
user perspective since the user is going to use the system. In particular system. But before test cases can be generated, the
order to make sure that the system does the requirements as flow of events for each use cases must be defined first. As an
it supposed to do, the test cases are designed according to the example of one particular use case, Place an Order, the
tester perspective. These test cases are basically designed to expected flow of events and its exceptions are shown in
test the input and output of a system. Most often, the input, Table 1.
key-in by the user, will be accepted by the system. The
system then processes the input and produces the required Table 1:Place an Order Event Flow
output according to its specification. Place an Order Event Flow

In this paper, we present an example of online 1. User enters web site address in the browser.
bookstore system. The requirements of the system include
2. User enters an email address and a password.
the capability to make an order, cancel the order and check Exception 1: email address and a password is
the status of his/her order. These three requirements are then not valid.
transformed into a use-case diagram as shown in Figure 1. • Log event
• Use case ends

3. User enters search string – partial name of a book.

Exception 2: No books matching search criteria
were found
• Log event
• Use case ends

4. User selects a book.

Exception 3: Decline a book
• Log event
• Use case ends

ISBN 978-979-16338-0-2 700

Proceedings of the International Conference on C-24
Electrical Engineering and Informatics
Institut Teknologi Bandung, Indonesia June 17-19, 2007

5. User adds the book to a shopping cart. Test Condition 5:

Continue shopping after storing a book in the shopping
6. User selects "proceed to checkout" option. cart
Exception 4: Continue shopping after storing a • An email address and a password.
book in the shopping cart • Matching search string were found
• Log event • Selects the book.
• Use case ends • Leave the book and select another book
• Verify event is logged
7. User confirms shipping address.
Exception 5: Enter a new address Test Condition 6:
• Log event Enter a new address
• Use case ends • An email address and a password.
• Matching search string were found
8. User selects shipping option. • Selects a book and add the book to a shopping cart
• Make a correction on the shipping address
9. User confirms credit card that is stored in the • Change the shipping address.
system.
• Verify event is logged
Exception 6: Enter a new credit card
• Log event Test Condition 7:
• Use case ends Enter a new credit card
• An email address and a password.
10. User places the order.
• Matching search string were found
Exception 7: Cancel order
• Selects a book and add the book to a shopping cart
• Log event
• Confirms shipping address and shipping option.
Use case ends
• Enter invalid credit card number.
• Change credit card number
From Table 1, sequence diagrams are formed to • Verify event is logged
record scenarios of the test cases. Based on Table 1 and test
scenarios in sequence diagrams, we have derived the Test Condition 8:
following test cases as shown in Table 2. Cancel order
• An email address and a password.
Table 2: Place an Order Test Case • Matching search string was found.
Place an Order Test Case • Selects a book and add the book to a shopping cart.
• Confirms shipping address and shipping option.
Test Condition 1: • Confirms credit card.
Basic flow of event – valid account/data is entered. • Click on cancel order button.
• An email address and a password. • Sign out of the account without place an order.
• Matching search string were found • Verify event is logged.
• Selects a book and add the book to a shopping cart
• Confirms shipping address and shipping option.
• Confirms credit card 4. The tool
• Places the order The tool, which we call GenTCase (Generator for
Test Cases), can be used to layout the use-case diagram of
Test Condition 2:
any system. The tool is also able to automatically generate
Email address and a password is invalid.
• Enter wrong combination of an email address and a
the test cases of the system according to the use-case
password diagram that has been formed previously. The tool is
• Enter unavailable of email address or password. developed using object-oriented approach with C++
• Verify event is logged programming language. The tool has 3 major components as
shown in Figure 2.
Test Condition 3:
No books matching search criteria were found
• An email address and a password.
• Enter search string which is not spelled correctly. Workspace Î Engine Î Test
• Verify event is logged.
Cases
Test Condition 4:
Decline a book
• An email address and a password. Figure 2: Components of GenTCase
• Matching search string was found.
• Enter a new search string. From Figure 2, the tool allows a user to layout the
• Verify event is logged use-case diagram of any system in the workspace provided.
The workspace is used as a place for a user to provide the
system’s requirements by means of a use-case diagram. In

ISBN 978-979-16338-0-2 701

Proceedings of the International Conference on C-24
Electrical Engineering and Informatics
Institut Teknologi Bandung, Indonesia June 17-19, 2007

the workspace, a ToolBox is used to create, edit and display generator of test cases (GTC) in the Workspace can be used
the use-case diagram. The ToolBox consists of standard to generate the test cases.
symbols and arrows for a use-case diagram such as symbols
for an actor and a use case, and arrows for connecting an 5. Conclusion and Future Work
actor with use cases as well as arrow for generalizations. In GenTCase is a tool that is able to generate the test
the Workspace, a user can also type-in the text for each of cases automatically according to the system’s requirements.
the use cases used in the Text Box provided by the tool. The The test cases can be used as a checklist for a programmer to
Workspace will allow a user of the tool to layout the use- validate that the system meets its requirements. The purpose
case diagram according to any system. of GenTCase is to reduce the cost of testing the system.
However, GenTCase has its limitations where the use cases
Once the use-case diagram has been finalized, the used are only for functional requirements of a system. The
user can generate the test cases by using the generator of the tool is unable to capture the non-functional requirements of a
tool. The Engine will take all the use cases and search the system. Therefore, the non-functional requirements need to
keywords used in the provided database. The database be captured and tested outside of the tool.
consists of most standard keywords of a use case. Once the
use case used matches the keyword inside the database, the
engine will generate its respective test cases according to its 6. Acknowledgements
use case. Intelligent search technique is used to search all the This research is under UTHM Fundamental
metadata fields in the entire database. Research Grant Vot 0233.

The intelligent searching technique includes three 7. References

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also be used to validate the results of the test cases so the
requirements of the system are meet.

User who uses the tool can layout the use cases
using the Workspace. The Tool Box is used in order to ease
the drawing of the use-case diagram. Then, the button for

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