Testing Computer Software phần 8 docx

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Printer compatibility table

There are over 1000 printers on the market, and most of them emulate (work just like) other printers. If 50

printers all emulate the Hewlett Packard LaserJet II, don't test all 50 printers.

We've found it useful to create charts, along the lines of Figure 12.16, that show what printers are compatible

with what others. (You can create similar charts for other devices but here, as in Chapter 8, we'll stick with

printers as our model device.) Formats vary widely. All charts contain some of the following columns:

• Printer: make and model.

• Mode: some printers can be set in their own native mode, or to emulate a few other, different, printers.

• Compatibility: make and model of the printer this one emulates.

• Source: how do you know this printer emulates that one? Name the magazine article, the person, the

advertisement. Some reports are much more trustworthy than others.

• Tested: indicate whether your lab has tested this printer's compatibility and what test was used. Have

you confirmed graphic mode compatibility? Escape sequence command compat

ibility? Character set compatibility?

• Notes: list incompatibilities, doubts, customer reports, etc.

Boundary Chart

See "Equivalence classes and boundary values" in Chapter 7 for a detailed discussion of

equivalence class and boundary chart development. Figure 12.17 illustrates a boundary

analysis of some of the input variables used in the Problem tracking system.

Don't expect to complete this chart early in testing. It takes a long time to do this chart well. Start by listing

every input field (use the input variable list if you made one). Identify their functions. Assign limit values and

further information as you learn more, but let yourself experiment with the variables from a full list from as

early a time as you can.

OUTLINES—THE FUNCTION LIST

Function lists outline what the program can do. They express your organization of the program's functions.

Organize them in a way that you'll find convenient for testing and test planning. We use a function list as the

core of our notes.

You can develop these lists to almost any level of completeness and detail. We suggest an incremental

approach. Start simple; add detail as you go. Figure 12.18 summarizes our approach.

You' 11 find it much easier and faster to add items and reorganize the list if you use an outline processor, rather

than a word processor. /

Figure 12.8 shows a basic, first draft, top-level list of the problem tracking system's functions. It shows

everything the program is supposed to do. This first step toward a more thorough outline is valuable in its own

right. Keep a copy at your desk while testing the program; check it as you go to make sure that you've tested

each function on the list. You can summarize the stability of different parts of the program by highlighting

working functions in one color and failing ones in another.