CS 3500 Assignment #2
Section:  Proulx
Assigned:  Friday, 14 September 2012
Due:  Friday, 21 September 2012

The purposes of this assignment are:

 * to construct black-box tests from a formal specification
 * to emphasize the distinction between clients and implementors

You will write a black-box test program for the FListString ADT as
specified below.  Collaboration between students is forbidden on
this assignment.  You are responsible for keeping your code hidden
from all other students.  Turn in your work on this assignment
before 10 pm on the due date by following instructions on the
course's main assignments web page,
http://www.ccs.neu.edu/course/cs3500wc/assignments.html

Your file of Java code should begin with a block comment that lists
    1.  Your name, as you want the instructor to write it.
    2.  Your email address.
    3.  Any remarks that you wish to make to the instructor.

Part of your grade will depend on the quality and correctness of your
code and black-box tests, part will depend on the readability of your
code (comments and indentation), and part will depend on how well you
follow the procedure above for submitting your work.  Late assignments
may be discounted, and very late assignments may be discarded.

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Your assignment is to write the code for a single file,
TestFListString.java, that implements a

    public static void main(String[])

method that, when called with any array of strings, performs
black-box testing of any and all implementations of the FListString
ADT that satisfy its specification given below.

(Note: Your main method should probably just ignore the
array of strings that it receives as an argument, since
you cannot rely on the number of strings or their content.)

A future assignment will require you to work with other students as
a team, implementing a black-box test program and using that program
to test implementations of the FListString ADT that were written by
other students.

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Specification of the FListString ADT.

FListString is an immutable abstract data type whose values represent
homogeneous linear lists of strings.

The FListString ADT shall be implemented in Java, and will be tested
using Sun's Java 2 Runtime Environment, Standard Edition, version 1.6.0.
The code for this implementation shall be in the default package, and
shall define a public class named FListString.  The operations of the
FListString class shall be provided by the following public methods of
of the FListString class:

Signature:

  Static methods:

    emptyList() :                             ->  FListString
    add         : FListString x String        ->  FListString
    isEmpty     : FListString                 ->  boolean
    get         : FListString x int           ->  String
    set         : FListString x int x String  ->  FListString
    size        : FListString                 ->  int

  Dynamic methods (for which the receiver is an FListString):

    toString    :               ->  String
    equals      : Object        ->  boolean
    hashCode    :               ->  int

Algebraic specification:

    FListString.isEmpty (FListString.emptyList())  =  true
    FListString.isEmpty (FListString.add (f, x))  =  false

    FListString.get (FListString.add (f, x), n)  =  x           if n == 0
    FListString.get (FListString.add (f, x), n)
        =  FListString.get (f, n - 1)                           if n > 0

    FListString.set (FListString.add (f, x), n, y)
        =  FListString.add (f, y)                               if n == 0
    FListString.set (FListString.add (f, x), n, y)
        =  FListString.add (FListString.set (f, n - 1, y), x)   if n > 0

    FListString.size (FListString.emptyList())  =  0
    FListString.size (FListString.add (f, x))  =  1 + FListString.size (f)

    FListString.emptyList().toString()  =  "[]"
    FListString.add (f, x).toString()
        =  "[" + x.toString() + "]"               if FListString.isEmpty (f)
    FListString.add(f, x).toString()
        =  "[" + x.toString() + ", "
               + f.toString().substring(1, f.toString().length())
                                                  if ! (FListString.isEmpty (f))

Values of the FListString ADT shall also implement the public
dynamic methods equals(Object) and hashCode() such that

    If f1 is a value of the FListString ADT, but x is not, then

        f1.equals(x) returns false.

    If f1 and f2 are values of the FListString ADT, then
        f1.equals(f2) if and only if:

            (f1.isEmpty() && f2.isEmpty())

         or ((f1.size() == f2.size())

             and

             for every integer i such that 0 <= i < f1.size()
                f1.get(i).equals(f2.get(i))

    If f1 and f2 are values of the FListString ADT, and

        f1.equals(f2)

    then f1.hashCode() == f2.hashCode().

    If f1 and f2 are values of the FListString ADT, and

        !(f1.equals(f2))

    then f1.hashCode() is unlikely to be equal to f2.hashCode().

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