pst presents test estimation and scheduling 201006

8/8/2019 PST Presents Test Estimation and Scheduling 201006

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and scheduling



Estimation vs. scheduling

Copyright © 2010 ps_testware

Estimation Scheduling

• Determine most likely

effort and cost

• Determine most likely

duration• Person days• Euros

• Start date• End date

• How much will it cost? • How long will it take?



Importance

Input for the

decision process


and resourceclaims

Required practicefor TMM level 2



Test estimation



Estimating test effort


Based on: Garmus & Herron; Estimating time, effort and cost; Software testing & quality engineering; STQE Publishing; Nov/Dec 1999 issue; p.32.



Estimating the cost of testing




Technical factors

complicating test estimation




A goal is not an estimate

Don't estimate what others want to hearA quick guess is not an estimate

Human factors

complicating test estimation


Danger of estimating your own work

Lack of historical data

Evolving technologies introduceuncertainty



Producing a good estimate ...

Scope Businessgoals, risks

Dependencies

other processes

Resource

availabilties

Approach


Prod. risks Proj. risks

Schedule

Deliverables

Tasks

Estimate

Effort

Size




Scope Businessgoals, risks

Approach

Dependencies

other processes

Resource

availabiltiesRBT

TRH


Deliverables

Tasks

Estimate

Effort

Size

Prod. risks Proj. risks

Schedule

WBS

WBDPBE

UCP

CPA

CCM




Scope Business

goals, risks

Dependenciesother processes

Resourceavailabilties

Approach


Deliverables

Tasks

Effort

Size

Test planSchedule

Estimate Prod. risks Proj. risks



Early vs. late estimates ...

Effort


Time

exec

+

Testdesign

Plan

Testingtasks

Test

exec Testexec

Test

design

Plan

Test

design

Plan



Test sc e u ing



Test scheduling

Translation test plan time line,

showing– When testing tasks will be performed

– Who will perform testing tasks

–


Important deliverable– Shows the feasibility of the test approach

– Understand how long testing will take– Understand resource needs

– Communicate who does what when

– Baseline for monitoring



Determine task durations

Determine how long each task will take

Basic formula:documentedin test plan


- How many are available?

- What is practical?- Skills needed?- Holiday planning, …Not perfectly

linear



Schedule uncertainty

– Estimation uncertainty/errors– External dependencies

– Scope changes

Adding contingency


Cascade effect– Delays add up

– Early finishes don’t



Contingency buffers solve the problem

Adding contingency




Add contingency




How to shorten the schedule?

Why shorten the schedule?

– Undo lengthening caused by resource leveling andcontingency buffers

– Make schedule meet a (realistic ) deadline

– Make up lost time


Factors to consider– Impact on other project variables

– Probability of success– Attractiveness for the project or organization



Techniques

Project crashing

Fast-tracking


LadderingPostpone non-essential testing

Adopt lighter test approach



Other way to deal with schedule

uncertainty

Sim le but effective techni ue

Time-boxing


– Available time is divided in fixed-size “time boxes” – Tasks are allocated to time box

– Tasks may not exceed box

Works well in testing– Test design, test scripting, ….



Recap

Difference

ImportanceComplexity, pitfalls


,

pitfalls



Q&A


pst presents test estimation and scheduling 201006

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