We have executed many projects Large Projects, Small Projects etc. Sometimes we miss our testing deadlines because there is no defined criterion that is used to build our execution test plan. To help avoid missing our deadlines we have prepared these Test Estimation guidelines. In this article I present the various Test estimation techniques which will help us in proper execution of the Testing projects.
Test Estimation is a prediction based on probabilistic assignments and is a continuous process, which should be followed and used through out the project life cycle. Effective software estimation helps track and control cost/effort overruns. Estimations cover following broad areas:
- Estimate size
- Estimate cost & effort
- Determine the schedule
- Assess risks
Now this brings us to a basic question: How can we do Test Estimations?
Test Estimations can be done as shown in the below figure.
There are various types of Test Estimations as shown below:
Software Test Estimation – Overview:
There are various issues which creep up while estimating:
- Major Issues
- Estimation method / Process
- Environment & Tools
- Testing to be performed
- Complexity of the application under tests
- Minor Issues
- Test Resource
- Other factors
Issues While Estimating – Environment & Tools
- Separate Environment
- Environment not similar to the deployment environment
- Downtime of the environment available during testing
- Availability of test management tools
- Availability of test automation tools
Issues While Estimating – Testing Resources
- Management commitment towards completion and following the test life cycle
- Common and realistic expectation toward the testing goal from all the stakeholder in project
- Availability of key resources
- Application knowledge among the test team
- Connect / Attitude between the development and testing team
- Correct resolution on the defect fixes
- Clear Communication
From the above we have got a basic idea about the facts related to Test estimations.
There are various software test estimation techniques:
- Simple Medium Complex (SMC) Method
- Top Down Method
- Bottom Up Method
- Test Point Analysis(TPA)
Now in the following sections I’d be explaining the above mentioned estimation techniques in detail.
This model will consider the test functions / test conditions and their
Complexities (Simple, Medium, Complex) as the basis for estimation and
The effort involved for the following test activities can be estimated using
This model. Following test activities could be covered
- Test Initiation
- Test Planning & Design
- Test Execution
- Test Closure activities
Effort estimate for the following activities can be done using SMC model under Initiation Phase:
- Knowledge Transfer
- Application Familiarity
- Requirements Analysis
- Functional Decomposition
Test Planning and Design:
Effort estimate for the following activities can be done using SMC model under Test Planning & Design Phase:
- Test Plan
- Preparation of Scenarios, Test Cases, Test Data.
- Test Case, Test Data Reviews
- Preparation of Execution Plan
- Test Ware Re-work & Reviews
- Prepare and Review of Zero-day checklist
Effort estimate for the following activities can be done using SMC model under Test Execution Phase:
- Verify zero day check list
- Creation of test bed
- Test Execution
- Review of Incident logs
- Update the Incident report
Effort estimate for the following activities can be done using SMC model under test closure Phase:
- Closure Metrics Preparation
- Closure meeting
- Archive project data (Project Closure Activities)
- Test / Project Management
I’m attaching a Sample SMC Sheet which I had used for one of my test projects.
Spreadsheet provided by author.
Top Down Method
In this method, the Overall effort estimate for the project is determined first in FP or Line of code method. The estimation procedure is as follows:
- Get the total size in FP
- Define the lower level project test component
- Based on experience and productivity data from previous projects, obtain the effort estimate
- Overall effort estimate = productivity *size
Bottom Up Method
This is also known as “divide and conquer” technique. It is hierarchical decomposition of the test effort into stages, activities and tasks.
- Test environment & configuration
- Test case creation
- Test execution
Again decompose the above activity in smaller packages which can be estimated in short period of time. Estimate the total effort by understanding the duration and effort of each activity.
Test Point Analysis (TPA)
Test Point Analysis can be used to objectively prepare an estimate for black box testing (excluding performance testing). Test Case Point Analysis methodology is based on Test Case Points. Test Case Point is a Verification Point used to verify that the value on AUT matches with the expected value. This O/p value can be I/p data for other verification points. Following factors will have influence on number of Test Case Points:
- Complexity: It relates to the number of conditions in a function. More conditions almost mean more test cases and therefore a greater volume of testing work.
- Interfacing: The degree of interfacing of a function is determined by number of data sets maintained by a function and the number of other functions, which make use of those data sets.
- Uniformity: The extent to which the structure of a function allows it to be tested using existing or slightly modified specifications, i.e. the extent to which the information system contain similarly structured functions.
Details about Test Case Point are as follows:
- Low Complexity Test Case Point: A Test Case Point having 1 to 3 Steps is considered as Low Test Case Point.
- Medium Complexity Test Case Point: A Test Case Point having 3 to 4 Steps is considered as Medium Test Case Point.
- Critical Complexity Test Case Point: A Test Case Point having 5 to 6 Steps is considered as Critical Test Case Point.
Test Scripts can be defined in following three Complexity Levels:
|1||Critical||If a Test Script is having 6 to 8 Test Case Points Or Verification Points.|
|2||Medium||If a Test Script is having 4 to 5 Test Case Points Or Verification Points.|
|3||Low||If a Test Script is having 1 to 3 Test Case Points Or Verification Points.|
Breakdown between Testing Phases:
|Test Phase||% Age|
(includes Functional Understanding)
(includes Test Conditions, Test Data identification, Test Script preparation)
|Test Execution||Test Script Execution and Defect Management
(includes Smoke, System, Integration, End to End and Regression Test)
Factors affecting Test Estimation
- Productivity Figure: It is based on knowledge and skill of test team members and is therefore specific to the individual organization. Productivity figure mentioned in these guidelines needs to be verified for couple of projects before implementation across GSI.
- Environmental Factor: Following environmental factors should be consider for test effort estimation:
- Test Tools: It reflects the extent to which testing is automated, or the extent to which automation tools are used for testing.
- Development Testing: It reflects the extent to which the development testing is down, a development test plan is available and test team is familiar with the actual test cases and test results
- Test Base: It reflects the quality of system documentation upon which the test under consideration is to be based.
- Test Environment: It reflects the extent to which the test infrastructure in which the testing is to take place has previously been tried out.
- Testware: It reflects the extent to which the tests can be conducted using existing testware.
- Multiple Browsers: Effort estimation for testing on multiple browsers is more then testing on one browser.
The estimation technique guidelines explained in the earlier section can be enhanced to cover the various environmental factors. Pilot these guidelines for couple of projects in your organization and compare the estimated effort and actual effort. As we get proficient with its implementation we’ll find that Estimated and Actual efforts are getting closer which will result in better execution of the testing projects.
I’m also attaching a sample Testing Estimation Sheet created by me and which I’ve used extensively. This estimation tool has been successfully implemented also in my previous organizations.
Spreadsheet provided by author.
[Note: The attached template is just a snapshot of the actual tool.]
Definitions, Abbreviation and Acronyms
QA – Quality Assurance
SEPG – Software Engineering Process Group
SMC – Simple Medium Complex Method
TPA – Test Point Analysis
FP – Function Point
UAT – User Acceptance Testing
The whole content has been written based upon my past experiences in various organizations. The views may differ based upon circumstances. Feel free to get back to me at firstname.lastname@example.org in case of any clarifications.
About the Author
Shyam Sunder Shyam Sunder is a PMP® Certified Test Program Manager working in Dell Services. Shyam has got total IT Testing Experience of 14.9 Years and has worked in various reputed organizations like IIS Infotech, HCL Technologies etc before joining Dell. Shyam is strong in the area of Test Management, Software Testing areas and Client relationship management. He is well versed in testing areas and has been actively involved in IV&V along with his testing delivery projects. The strong testing background which Shyam inculcated in previous organizations is being put into forte in Dell which is reaping rich dividends of his testing acumen and expertise. Shyam has a consistent track record of successful product introduction and implementation. And is Productive as both individual contributor and Project Manager. Shyam also possesses excellent communication and relationship-building skills.
Shyam has been a regular contributor in Testing Forums like Quality Assurance of India (QAI), Software Testing Conferences (STC) etc with his papers, presentations and workshops.
Shyam has received excellent Client testimonials which can be seen in his linked-in profile.
Linked in Profile: http://www.linkedin.com/in/sundershyam30
Shyam’s Professional Certifications
-PMI Certified PMP®.
-6-Sigma Green Belt Champion.
-KPMG Certified IS0 9001 Internal Auditor.
-Brainbench Certification in Project Management.