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COMP3211 Software Engineering

Fall 2023

Assignment 2

Handout: Wednesday, 8 November 2023

Due: 23:59, Saturday, 18 November 2023

1. Class Diagram (13 marks)

Please read the following description, design the classes and their relations for the system, and draw the  corresponding  UML  class  diagram.  Note  that  you  need  to  choose  the  appropriate  types  of associations, but you do NOT need to specify the multiplicities for the associations. Your design should support all the requirements mentioned in the text.

An order management system keeps track of various products in stock and  orders. For each product, its name, price, and quantity in stock are recorded. Both the price and quantity of a product may be updated. The system has two  types of customers, namely companies and persons, and for each customer,  the system records its phone number and address. Besides, the first and last  names of persons and the government registration numbers of companies are  recorded. All customers can place orders. The information associated with  an order includes the customer, date, and order items. An order item is for  a specific product, and it also specifies the quantity of the product as  well as the price of the product at the time the order item was created.  When creating an order item, an order to which the new order item belongs  must be specified, and the newly created order item will be added to the  order automatically. Order items may not be removed from an order.

2. Layered Architecture (15 marks)

A utility company wants to develop an information system to maintain information about assets like  buildings, vehicles, and equipment owned by the company. It is intended that the information will be  updatable by staff working in the field using mobile devices as new asset information becomes available. The company has several existing asset databases that should be integrated through this system.

Given the system’s layered architecture as shown above and the following system modules (a) through (j), please decide which modules should be placed in which layers.

(j) vehicle database

3. Software Testing (12 marks)

Suppose a developer has written a method named canFormTriangle, as shown on the next page, that a) takes three double parameters named x, y, and z as the input, b) treats the input values as denoting the lengths of three line segments, and 3) returns a boolean value indicating whether the three line segments can legitimately form a triangle. Note that three line segments of lengths x, y, and z can legitimately form a triangle if and only if they satisfy the following two conditions: a) x, y, and z are all greater than 0; b) the sum of any two of them is greater than the third.

1 boolean canFormTriangle(double x, double y, double z){

2 if(x <= 0 || y <= 0 || z <= 0)

3 return false;

4

5 if(x + y <= z)

6 return false;

7 else if(x + z <= y)

8 return false;

9 else if(y + z <= x)

10 return false;

11 else

12 return true;

13   }

Please apply partition testing to devise a set T of unit tests for method canFormTriangle such that, for every possible unit test t of the method, there is a unit test t' in T satisfying that t and t' have the same branch coverage on the method. Here, two tests t1 and t2 are said to have the same branch coverage on a method if and only if both conditions 1) and 2) are satisfied: 1) t1 and t2 exercise the same set of if statements in the method; 2) for each if statement exercised by both t1 and t2, the corresponding if condition expression evaluates to the same value during t1 and t2’s executions. For example, if both tests t1 and t2 exercise only the first if statement in method canFormTriangle and the condition expression on line 2 evaluates to true in both tests, t1 and t2 are said to have the same branch coverage on method canFormTriangle. Write down all your tests, with one test on each line.

For each test, you need to specify the values of parameters x, y, and z, the expected return result from the method, and the branches covered by the test. In the example below, c2==true indicates that only the if condition on line 2 is evaluated during the test execution and the condition evaluates to true. You may separate the branches using commas.

x    y    z    ExpectedResult    BranchesCovered

1    1    -1   false             c2==true

4. Software Maintenance (10 marks)

As introduced in lecture one, there are four main types of maintenance in the modern view of software maintenance. Briefly describe the four main types and explain why it is sometimes difficult to distinguish between them. (≤200 words)

How to hand in:

Submit your typed, instead of handwritten, answers in a PDF file on Blackboard.