CSE 7314Software Testing and Reliability

Robert Oshana

Lecture 16

oshana@airmail.net

Test execution

Chapter 7

Test execution

• Most visible part of the process

• Occurs at the end of the development cycle– Most other activities have slowed down– Probably on critical path

• Test execution is 40% of the entire effort

Executing the tests

Who should run tests

• Unit tests – probably the developers

• System tests – combination of developer, end user, test team

• Acceptance test – end user

• Look for the right people !

What to execute first

• A strategy decision– Quality of resources– Documentation– Risk analysis

• Run regression test to find problems early

• Then focus on high risk areas

Writing test cases during execution

• Will always think of new test cases

• You are learning more about the system

• Make sure to log these new tests and record them

Record results of testing

• Automation should require that inputs and outputs be logged

• Manual testing can record results right in the test log

• Material to put in the log will vary

• IEEE 829-1998 defines the test log as a chronological ordering of events

Test incident reports

• Incident defined as any unusual result of executing a test (or actual operation)

• May later be categorized as defects or enhancements

• Failure occurs when a defect prevents a system from accomplishing its mission

• Defect tracking becomes an important activity

IEEE Template for test incident reporting

• Identifier

• Summary

• Description

• Impact

• Investigation

• Metrics

• Disposition

CSE 7314Software Testing and Reliability

Robert Oshana

End of Lecture

oshana@airmail.net

CSE 7314Software Testing and Reliability

Robert Oshana

Lecture 17

oshana@airmail.net

Writing the test incident report

• Focus on factual data

• Ensure the situation is re-creatable

• Not use emotional judgment

• Not be judgmental

Attributes of a defect tracking tool

• Commercial or custom solutions

• Easy to use and flexible

• Fields should be modifiable to match the organization terminology

• Should facilitate the analysis of data

• Linked to CM system

Testing status and results

• Test status report is often the primary formal communication channel that the test manager uses

Test summary report (IEEE 829)

• Identifier

• Summary

• Variances

• Comprehensive assessment

• Summary of results

• Evaluation

• Recommendations

Test summary report (IEEE 829)

• Summary of activities

• Approvals

When are we done testing?

• “There is no single, valid, rational criterion for stopping. Furthermore, given any set of applicable criteria, how each is weighed depends very much upon the product, the environment, the culture, and the attitude to risk”

If you stop too early

• Many defects left in the product, including show stoppers

• Might be manageable with a small number of customers with expectations set

• May be difficult to switch to new product needs

• Increased employee turnover• Customer frustration with the product

Shipping too late

• Team confidence in product quality

• CS – smaller, predictable

• Loss of revenue, market share

• Greater quality => reputation increases => market share

Defect discovery rate

CSE 7314Software Testing and Reliability

Robert Oshana

End of Lecture

oshana@airmail.net

CSE 7314Software Testing and Reliability

Robert Oshana

Lecture 18

oshana@airmail.net

Measuring test effectiveness

• Many organizations do not consciously attempt to measure test effectiveness

• All measures have deficiencies

• Should still develop a method to use in your organization

Categories of metrics for test effectiveness

Defect discovery rates

Bug budget example

Defect removal efficiency (DRE)

Number of bugs found in testing

DRE = ---------------------------------------------

# bugs found in testing + # not found

Defect removal efficiency (DRE)

• Severity and distribution of bugs must be taken into account

• How do you know when the customer has found all the bugs?

• Metrics are “after the fact”• When do we start counting bugs?• Some bugs cannot be found in

testing

# defects weighted by defect age on a project

Formula for defect spoilage

Sum of (# defects X defect phase dis)

Spoilage = -------------------------------------- total number of defects

Formula for defect density

Code coverage

• Not a silver bullet• Tools available• Several weaknesses

– Does not assure code will work

• More effective when used at lower levels

• Global coverage can highlight areas that are deficient

CSE 7314Software Testing and Reliability

Robert Oshana

End of Lecture

oshana@airmail.net

CSE 7314Software Testing and Reliability

Robert Oshana

Lecture 19

oshana@airmail.net

The Test Organization

Chapter 8

Test organizations

• No right or wrong way to organize

• Dependent on politics, corporate culture, skill, knowledge of the participants, risk of the product

Independent test teams

• Primary job is testing

• One product or many

• Popularity grown out of frustration

• Could lead to a “brick wall” between developers

Integrated test teams

• Teams made up of developers and testers who all report to the same manager

• May be easier to get buy in earlier if working on a team

• Professional testers• Under pressure, may ship product

prematurely

Developers

• Developers and testers are the same people

• Fewer communication problems• Lack of unbiased look at the system• Reduce risk by having a rigorous test

process, adequate time, business expertise, CM enforced, training, and exit criteria

Other organizational approaches

• Test coordinator

• QA

• Outsourcing

• IV&V

Office environment

• Office space

• Location relative to other participants

• Cube vs office vs common office

• Immersion time

number of uninterrupted hoursE-Factor = ---------------------------------------

Number of body present hours

Office environment

• Quiet time• Meetings

– Start meeting on time– Publish an agenda– Specify who should attend– Keep attendees to a workable number– Limit conversations– Have someone take notes– Urge participation– Choose a suitable location

The software tester

Chapter 9

Characteristics of good testers

• Inquisitive• Functional/business knowledge• Detail oriented• Open minded• Good personality• Technical background• Testing experience• Team player

Finding good testers

• Developers

• Users

• Help desk/technical support

• Technical writers

• QA personnel

• Recent graduates

• Other companies

Hiring testers

• Define job requirements

• Read the resume

• Prepare yourself mentally

• First impressions are important

• Learn how to ask questions

• Ask to demonstrate skills

• Take notes

Hiring testers

• Answer candidates questions

• Check references

• Team interviews

Other test organization issues

• How many testers do you need?

• Retaining staff

• Working overtime

• Software testing certifications

Categories of certifications

CSE 7314Software Testing and Reliability

Robert Oshana

End of Lecture

oshana@airmail.net