Consider the following task of test generation for a GUI based computer purchase system.

A web$-$based company is selling computers $($CPU$),$ printers $($PR$),$ monitors $($M$),$ and additional memory $($RAM$).$

An order configuration consists of one to four items as shown below.

CPU $1$ PR $1$ M $20$ RAM $256$

CPU $2$ PR $2$ M $23$ RAM $512$

CPU $3$ M $30$ RAM $1$G

The GUI consists of four windows for displaying selections from CPU, Printer, Monitor and RAM and one window where any free giveaway items are displayed. For each order, the buyer may select from three CPU models, two printer models, and three monitors. There are separate windows, one each for CPU, printer, and monitor that show the possible selections. For simplicity, assume that RAM is available only as an upgrade and that only one unit of each item can be purchased in one order. Monitors M $20$ and M $23$ can be purchased with any CPU or as a stand$-$alone item. M $30$ can only be purchased with CPU $3.$ PR $1$ is available free with the purchase of CPU $2$ or CPU $3.$ Monitors and printers, except for M $30,$ can also be purchased separately without purchasing any CPU. Purchase of CPU $1$ gets RAM $256$ upgrade. Purchase of CPU $2$ or CPU $3$ gets a RAM $512$ upgrade. The RAM $1$G upgrade and a free PR $2$ is available when CPU $3$ is purchased with monitor M $30.$ When a buyer selects a CPU, the contents of the printer and monitor windows are updated. Similarly, if a printer or a monitor is selected, contents of various windows are updated. Any free printer and RAM available with the CPU selection is displayed in a different window marked $$Free$.$ The total price, including taxes, for the items purchased is calculated and displayed in the $$Price$$ window, as shown below. Selection of a monitor could also change the items displayed in the $$Free$$ window. Sample configurations and contents of the $$Free$$ window are given below.