Black Box Software Testing Copyright 2003 Cem Kaner James Bach 499 Black Box Software Testing Part...

1Black Box Software Testing Copyright © 2003 Cem Kaner & James Bach

Black Box Software Testing

Part 12.

Introduction toTest Documentation

Co-authors: Cem Kaner & James Bach

AcknowledgementSome of this material is from the Third Los Altos Workshop on Software Testing (LAWST), February 7 and 8, 1998. I founded the LAWST and was co-organizer of LAWST 3. At LAWST, we discussed test documentation (test planning strategies and materials). The agenda item was:

• How do we know what test cases we have? How do we know which areas of the program are well covered and which are not? • How do we develop this documentation EFFICIENTLY? As many of you know, I despise thick test plans and I begrudge every

millisecond that I spend on test case documentation. Unfortunately, some work is necessary. My question is, how little can we get away with, while still preserving the value of our asset?

The following people attended LAWST 3: Chris Agruss, James Bach, Karla Fisher, David Gelperin, Kenneth Groder, Elisabeth Hendrickson, Doug Hoffman, III, Bob Johnson, Cem Kaner, Brian Lawrence, Brian Marick, Thanga Meenakshi, Noel Nyman, Jeffery E. Payne, Bret Pettichord, Johanna Rothman, Jane Stepak, Melora Svoboda, Jeremy White, and Rodney Wilson.


Copyright Notice

These slides are distributed under the Creative Commons License.

In brief summary, you may make and distribute copies of these slides so long as you give the original author credit and, if you alter, transform or build upon this work, you distribute the resulting work only under a license identical to this one.

For the rest of the details of the license, see http://creativecommons.org/licenses/by-sa/2.0/legalcode.


Definitions• The test planning documents include:

– The Testing Project Plan, which identifies classes of tasks and broadly allocates people and resources to them;

– High-level designs for test cases (individual tests) and test suites (collections of related tests);

– Detailed lists or descriptions of test cases;– Anything else that you would put in a hard copy or virtual

binder that documents the collection of test cases that you will develop and run.

• This collection of materials is sometimes called the test plan and sometimes called the test documentation.


Levels of Analysis• 1-Variable

– Basic user interface verification– Filters– Many testers stop here, at the most superficial level of testing

• 2-Variable– Shared or related filters– Logical relationships among variables

• Multi-Variable– The core problem is the vastness of the space of test cases. We

need a sampling strategy.


Basic Test Documentation Components• Lists:

– Such as lists of fields, error messages, DLLs• Outlines: An outline organizes information into a hierarchy of

lists and sublists– Such as the testing objectives list later in the course notes

• Tables: A table organizes information in two dimensions showing relationships between variables.– Such as boundary tables, decision tables, combination test tables

• Matrices: A matrix is a special type of table used for data collection.– Such as the numeric input field matrix, configuration matrices

» Refer to Testing Computer Software, pages 217-241. For more examples, see page Testing Computer Software, page 218.


Configuration Planning Table

Var 1 Var 2 Var 3 Var 4 Var 5

Config 1 V1-1 V2-1 V3-1 V4-1 V5-1

Config 2 V1-2 V2-2 V3-2 V4-2 V5-2

Config 3 V1-3 V2-3 V3-3 V4-3 V5-3

Config 4 V1-4 V2-4 V3-4 V4-4 V5-4

Config 5 V1-5 V2-5 V3-5 V4-5 V5-5

Config 6 V1-6 V2-6 V3-6 V4-6 V5-6

This table defines 6 standard configurations for testing. In later tests, the lab will set up a Config-1 system, a Config-2 system, etc., and will do its compatibility testing on these systems. The variables might be software or hardware choices. For example, Var 1 could be the operating system (V1-1 is Win 2000, V1-2 is Win ME, etc.) Var 2 could be how much RAM on the computer under test (V2-1 is 128 meg, V2-2 is 32 meg., etc.). Var 3 could be the type of printer, Var 4 the machine’s language setting (French, German, etc.). Config planning tables are often filled in using the All Pairs algorithm.


Configuration Test Matrix

Config 1 Config 2 Config 3 Config 4 Config 5 Config 6

Test 1 Pass Pass Pass Pass Pass

Test 2 Fail Pass Pass Pass

Test 3 Pass Pass Pass Pass Pass

Test 4 Pass Fail Fail Pass

Test 5 Fail Pass Fail Pass Pass

This matrix records the results of a series of tests against the 6 standard configurations that we defined in the Configuration Planning Table.

In this table, Config 1 has passed 3 tests, failed 1, and hasn’t yet been tested with Test 2. Config 6 is still untested.



Part 13.

Scripting:

An Industry Worst Practice


Scripting

• COMPLETE SCRIPTING is favored by people who believe that repeatability is everything and who believe that with repeatable scripts, we can delegate to cheap labor.

1 ____ Pull down the Task menu 2 ____ Select First Number3 ____ Enter 34 ____ Enter 25 ____ Press return6 ____ The program displays 5


Scripting: Another script format

Step #

Check?

What to do

What to see

Design notes

Observation notes

1. ____ Pull down task menu

Task menu down

This starts the blah blah test, with the blah blah goal


Scripting: The Bus of Testing

– Scripting is the Greyhound Bus of software testing:

“Just relax and leave the thinking to us.”

– To the novice, the test script is the whole tour. The tester goes through the script, start to finish, and thinks he’s seen what there is to see.

– To the experienced tester, the test script is a tour bus. When she sees something interesting, she stops the bus and takes a closer look.

– One problem with a bus trip. It’s often pretty boring, and you might spend a lot of time sleeping.


Scripting (Manual Test Cases)

Worst of all worlds:

• Not automated

• Not maintainable

• No communication of analysis

• NOT REPEATABLE!


Scripting

Should we create scripts as pseudocode, in preparation for test automation?

• Suggestion made at STAR 97• But most (88%) of bugs were found during

creation of the scripts (my experience too).

Maybe the benefit lies in structured exploration, rather than regression.


Never Do ANY kind of Scripting?• Checklists (as distinct from scripts) have their place. For

example, think of releasing a product:– Many very different tasks– All of them must be done– The task is rarely done, so many steps may be forgotten.

• I prefer to tell testers what to test (what issues to cover), not how to do the tests. Teaching people “how” is a matter of training, not something that I record time and time again in the test plan. A checklist will sometimes be the right way to present the list of issues.

• I think the level of detail is sufficient if I can successfully pass the section to a reasonably experienced tester who is a little familiar with the program and be confident that she can figure out what the test cases are and how to run them.



Part 14.

Requirements Analysis for Test Documentation


Problems with the (allegedly) standard approach

• It is essential to understand your requirements for test documentation.

• Unless following a “standard” helps you meet your requirements, it is empty at best, anti-productive at worst.



• IEEE Standard 829 for Software Test Documentation– Test plan– Test-design specification– Test-case specification

• Test-case specification identifier• Test items• Input specifications• Output specifications• Environmental needs• Special procedural requirements• Intercase dependencies

– Test-procedure specification– Test-item transmittal report– Test-log

We often see one or more pages per test case.



– What is the documentation cost per test case?– What is the maintenance cost of the documentation, per test case?– If software design changes create documentation maintenance

costs, how much inertia do we build into our system? How much does extensive test documentation add to the cost of late improvement of the software? How much should we add?

– What inertia is created in favor of invariant regression testing?– Is this incompatible with exploratory testing? Do we always want

to discourage exploration?



– What is the impact on high-volume test automation?– How often do project teams start to follow 829 but then give it up

mid-project? What does this do to the net quality of the test documentation and test planning effort?

– WHAT REQUIREMENTS DOES A STANDARD LIKE THIS FULFILL?

– WHICH STAKEHOLDERS GAIN A NET BENEFIT FROM IEEE STANDARD DOCUMENTATION?

– WHAT BENEFITS DO THEY GAIN, AND WHY ARE THOSE BENEFITS IMPORTANT TO THEM?


Standards:ISO 9000-3

• The basic thinking underlying ISO 9000 goes like this:– Decide what you’re going to do (create and document a process).– Do what you said you’d do.– Document what you’ve done in a way that lets an auditor check

what you’ve done against your process.• Risks

– It can be difficult to build in room for exploratory testing. To some degree (perhaps a large degree), this depends on the auditor.

– The style and extent of documentation needed to clue in a third party (auditor) might go beyond your internal needs. On finite budgets, where do we draw the line?

– What is the best tradeoff between process development and test execution? This must be a practical question, not a religious question.


Requirements

– There are many different notions of what a good set of test documentation would include. Before spending a substantial amount of time and resources, it’s worth asking what documentation should be developed (and why?)

– Test documentation is expensive and it takes a long time to produce. If you figure out some of your main requirements first, you might be able to do your work in a way that achieves them.


Defining documentation requirements

– Stakeholders, interests, actions, objects• Who would use or be affected by test documentation?• What interests of theirs does documentation serve or disserve?• What will they do with the documentation?• What types of documents are of high or low value?

– Asking questions– Context-free questions– Context-free questions specific to test planning– Evaluating a plan


Discovering Requirements

• Requirements– Anything that drives or constrains design

• Stakeholders– Favored, disfavored, and neutral stakeholders

• Stakeholders’ interests– Favored, disfavored, and neutral interests

• Actions– Actions support or interfere with interests

• Objects


What is your group’s mission?• Find important problems• Assess quality• Certify to standard• Fulfill process mandates• Satisfy stakeholders• Assure accountability

• Advise about QA• Advise about testing• Advise about quality• Maximize efficiency• Minimize time• Minimize cost

The quality of testing depends on which of thesepossible missions matter and how they relate.

Many debates about the goodness of testingare really debates over missions and givens.


Test Docs Requirements Questions• Is test documentation a product or tool?• Is software quality driven by legal issues or by market

forces?

• How quickly is the design changing?

• How quickly does the specification change to reflect design change?

• Is testing approach oriented toward proving conformance to specs or nonconformance with customer expectations?

• Does your testing style rely more on already-defined tests or on exploration?

• Should test docs focus on what to test (objectives) or on how to test for it (procedures)?

• Should the docs ever control the testing project?


Test Docs Requirements Questions

• If the docs control parts of the testing project, should that control come early or late in the project?

• Who are the primary readers of these test documents and how important are they?

• How much traceability do you need? What docs are you tracing back to and who controls them?

• To what extent should test docs support tracking and reporting of project status and testing progress?

• How well should docs support delegation of work to new testers?

• What are your assumptions about the skills and knowledge of new testers?

• Is test doc set a process model, a product model, or a defect finder?


Test Docs Requirements Questions

• A test suite should provide prevention, detection, and prediction. Which is the most important for this project?

• How maintainable are the test docs (and their test cases)? And, how well do they ensure that test changes will follow code changes?

• Will the test docs help us identify (and revise/restructure in face of) a permanent shift in the risk profile of the program?

• Are (should) docs (be) automatically created as a byproduct of the test automation code?


Example: Early vs. Late Planning• Benefits of early planning

– Scheduling and staffing (unless things change)– Early opportunity to review (if people can understand your work)

• Costs of early planning– Any delays in finding bugs are expensive. You should start finding

bugs ASAP.– Early investment in test case design is risky if the product design is

subject to change.– You will keep learning over time. Planning early sometimes

precludes groups from inventing new tests later.– Depth of testing should reflect risks, many of which are unclear until

mid-project.• MY USUAL GOAL: Do just-in-time test planning without losing key

benefits of early work.


Ultimately, write a mission statement

• Try to describe your core documentation requirements in one sentence that doesn’t have more than three components.

• Examples:– The test documentation set will primarily support our efforts to

find bugs in this version, to delegate work, and to track status.– The test documentation set will support ongoing product and test

maintenance over at least 10 years, will provide training material for new group members, and will create archives suitable for regulatory or litigation use.

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