Lab 1: Unit Testing

Objectives

During this lab session:

Students will write Ruby code and develop unit tests to verify its functionality.

This activity helps students develop the following skills, values and attitudes: ability to analyze and synthesize, capacity for identifying and solving problems, and efficient use of computer systems.

Activity Description

This lab can be developed individually or in pairs.

Take a quick glance at the documentation for the Ruby Unit Testing Framework. This information will come in handy in a later step.
Create a folder called deque. Inside this folder, create two files called deque.rb and test_deque.rb.

Both Ruby source files must start with a comment containing the lab's title, date, and the authors' personal information. For example:
```
# Lab 1: Unit Testing
# Date: 20-Aug-2009
# Authors:
# 456654  Anthony Stark 
# 1160611 Thursday Rubinstein
```

In the deque.rb source file, write a class called Deque (pronounced deck) that implements a double-ended queue. A deque is a data structure that implements a queue for which elements can only be added to or removed from the front or back.

The following table describes the operations that this class must provide:

Instance Method	Description
`initialize(*elements)`	Initializes a new deque instance with all the arguments sent to this method.
`push_back(obj)`	Inserts obj at the back of this deque. Returns the deque itself, so that several operations can be chained together.
`push_front(obj)`	Inserts obj at the front of this deque. Returns the deque itself, so that several operations can be chained together.
`pop_back`	Removes the element from the back of this deque and returns it, or `nil` if the deque is empty.
`pop_front`	Removes the element from the front of this deque and returns it, or `nil` if the deque is empty.
`back`	Returns the element from the back of this deque without removing it, or `nil` if the deque is empty.
`front`	Returns the element from the front of this deque without removing it, or `nil` if the deque is empty.
`empty?`	Returns `true` if this deque contains no elements, otherwise returns `false`.
`length`	Returns the number of elements in this deque.
`size`	Alias for `length`.
`inspect`	Returns a string containing a human-readable representation of this deque. For example: `"front -> [1, 2, 3, 4] <- back"`.

In the test_deque.rb file, write a test case class that verifies that every method in the previous step works as requested. Make sure to cover all cases in your tests (for example, that nil is returned by front when a deque is empty, in addition to its regular behavior).

Deliverables

To hand in your lab work, follow these instructions:

Create a ZIP file with the full contents of the deque directory. Call this file deque.zip.
Using the Online Assignment Delivery System (SETA), deliver the ZIP file. Due date is Friday, August 21.

Evaluation

This activity will be evaluated using the following criteria:

100	The code works as requested.
60-90	The code works, but has some flaws.
20-50	The code doesn't work, but it seams that some amount of time was spent on it.
DA	The program was plagiarized.

Software Design and Architecture

Lab 1: Unit Testing

Objectives

Activity Description

Deliverables

Evaluation