Quality Assurance and Software Testing
Overview
1 Introduction
2 Levels of Testing
3 Test Types
4 Testing Types Vs Test Levels
5 Testing Techniques or Methods
6 Seven Testing Principles
7 Stages of Testing
Test Planning Activities
Analysis and Design
Implementation and Execution
Evaluating exit criteria and Reporting
Test Closure activities
8 Testing Methodologies
Verification and Validation
9 Defect Life Cycle
Quality Assurance and Software Testing
Introduction
What is Software Testing ?
Definition
Software testing is a process used to identify the correctness,
completeness and quality of developed computer software. It
includes a set of activities conducted with the intent of finding
errors in software so that it could be corrected before the product
is released to end users.
Quality Assurance and Software Testing
Introduction
What is Software Testing ?
Definition
In simple words, software testing is an activity to check that the
software system is defect free
Quality Assurance and Software Testing
Introduction
What is Software Testing ?
Definition
Testing is executing a program on a tiny sample of the input
domain
Two Important aspect of testing:
1 Dynamic technique
2 Optimistic approximation
Quality Assurance and Software Testing
Introduction
Why is Testing Important ?
Airbus A300
264 People dead
Quality Assurance and Software Testing
Introduction
Why is Testing Important ?
THERAC -25 RADIATION THERAPY
3 Dead and 3 Critically Injured
Quality Assurance and Software Testing
Introduction
Why is Testing Important ?
Failed Satellite Launch
1.2 billion lost
Quality Assurance and Software Testing
Introduction
Why is Testing Important ?
Software is buggy!
Cost of bugs: 60 B/year US Economy
On average: 1-5 bugs/KLOC
100 % correct mass market software is impossible
Quality Assurance and Software Testing
Introduction
Why is Testing Important ?
As you can see testing is important because software bugs can be
expensive or even dangerous
Quality Assurance and Software Testing
Introduction
Causes of Software Defects
Faulty requirements definition
Time Pressure
Complex Code
Many System Interactions
Coding errors
Complexity of Infrastructure
Changing technologies
Non compliance with standards
Quality Assurance and Software Testing
Introduction
Role of Testing in Software Development
Testing of systems and documentation can help to reduce the
risk of problems occurring during operation and contribute to
the quality of the software system
Software testing may also be required to meet contractual or
legal requirements, or industry specific standards
Quality Assurance and Software Testing
Introduction
Testing and Quality
Testing ensures that key functional and non functional
requirements are met
Testing measures the quality of software in terms of the
number of defects found, the tests run, and the system
covered by the tests
Do you think testing increases the quality of the software ?
Quality Assurance and Software Testing
Introduction
Testing and Quality
Testing cannot directly enhance quality. Testing can give
confidence in the quality of the software if it finds fewer or no
defects
Understanding the root causes of defect found
Testing is one component in the overall quality assurance
activity.
Quality Assurance and Software Testing
Introduction
Tester Roles
Quality Assurance
Quality Assurance(QA) is a way of preventing mistakes or defects
in manufactured products and avoiding problems when delivering
solutions or services to customers
Tester Roles
Functional Tester-is responsible for checking if the product
works based on business requirements
Automation Tester-is responsible for writing script that
automate testing rather than manual testing the functionality
Performance Tester-is responsible for testing the product on
different load and report the finding the developer
Mobile Tester- is responsible for testing the product on
different mobile devices
Pen Tester-is responsible for exposing all security flaws(SQL
Injection, Cross scripting, session hijacking,etc ) in the
Quality Assurance and Software Testing
Levels of Testing
Testing Levels
Unit
Test-
ing
Integration
Test-
ing
System
Test-
ing
Quality Assurance and Software Testing
Levels of Testing
Testing Levels
Acceptance
Test-
ing
Validation Testing
Regression
Testing
Alpha Testing
Beta Testing
Quality Assurance and Software Testing
Levels of Testing
Unit Testing
Algorithms and logic
Data structures(global and local)
Interfaces
Independent paths
Boundary conditions
Error handling
Quality Assurance and Software Testing
Levels of Testing
Integration Testing
Why Integration Testing ?
One module can have an adverse effect on another
Sub functions, when combined, may not produce the desired
major function
Individually acceptable imprecision in calculation may be
magnified to unacceptable levels
Interfacing errors not detected in unit testing may appear
Timing problems(in real-time systems) are not detectable by
unit testing
Resource contention problems are not detectable by unit
testing
Quality Assurance and Software Testing
Levels of Testing
Validation Testing
Determine if the software meets all of the requirement defined
in the SRS
Having written requirements is essential
Regression testing is performed to determine if the software
still meets all of its requirements in light of changes and
modifications to the software
Regression testing involves selectively repeating existing
validation tests, not developing new tests
Quality Assurance and Software Testing
Levels of Testing
Alpha and Beta Testing
Its best to provide customers with an outline of the things
that you would like them to focus on and specific test
scenarios for them to execute.
Provide with customers who are actively involved with a
commitment to fix defects that they discover
Quality Assurance and Software Testing
Levels of Testing
Acceptance Testing
Similar to validation testing except that customers are present
or directly involved.
Usually the tests are developed by the customer
Quality Assurance and Software Testing
Test Types
Test Types
A test type is focused on a particular test objective, which could be
any of the following:
Functional Testing
Non-Functional Testing
Structural Testing
Retesting related to Changes
Quality Assurance and Software Testing
Test Types
Functional Testing
The functions are what the system does
Many be described in work products such as a requirements
speciffication, use cases, or a functional specification
Types of functional testing include:
Security Testing- Investigates the functions relating to
detection of threats, such as viruses,from malicious outsiders
Interoperability Testing - Evaluates the capability of the
software product to interact with one or more specified
components or systems.
Quality Assurance and Software Testing
Test Types
Non-Functional Testing
It is the testing of ”how” the system works
Non-functional testing includes, but is not limited to:
Performance Testing- How many users can connect to the
system and how will that affect the performance of the
software
Load Testing - How will the system perform if we do a single
transaction so many times
Stress Testing - How will the system perform under very
tough circumstances, many users, many transactions, low
memory,..etc
Usability Testing- Is the system easy to use
Maintainability Testing- Is the system easy to maintain if we
need to fix a defect
Reliability Testing- Is the system reliable or does it crash
eventually
Portability Testing - Is the system easy to port from one
platform to another
Quality Assurance and Software Testing
Test Types
Structural Testing
Coverage is the exten that a structure has been exercised by a
testing, expresssed as a percentage of the items being covered
If coverage is not 100%, then more tests may be designed to
test those items that were missed to increase coverage.
Quality Assurance and Software Testing
Test Types
Retesting related to Changes
After a defect is detected and fixed, the software should be
re-tested to confirm that the original defect has been
successfully removed. This called confirmation testing or
retesting
Regression testing is the repeated testing of an already
tested program, after modification, to discover any defects
introduced or uncovered as a result of the changes
Quality Assurance and Software Testing
Testing Types Vs Test Levels
Testing Types Vs Test Levels
What kind of test types will be performed at each test levels ?
Functional Testing
Non-functional Testing
Structural Testing
Retesting related to changes
Quality Assurance and Software Testing
Testing Techniques or Methods
Testing Techniques
Two Important techniques of testing:
1 Black box testing
2 White box testing
Quality Assurance and Software Testing
Testing Techniques or Methods
Black Box Testing
Based on a description of the software(specification)
Cover as much specified behavior as possible
can not reveal errors due to implementation details
Quality Assurance and Software Testing
Testing Techniques or Methods
Black Box Testing Limitation
Specification: inputs an integer and print it
Example:
1 . v o i d p r i n t N u m B y t e s ( param ) {
2. i f ( param <1024) p r i n t f ( ”%d” , param ) ;
3. e l s e p r i n t f ( ”%dKB” , param / 1 2 3 ) ;
4. }
Limitation
It doesn’t reveal errors hidden in the implementation details
Quality Assurance and Software Testing
Testing Techniques or Methods
White Box Testing
Based on the code
Cover as much coded behavior as possible
Quality Assurance and Software Testing
Testing Techniques or Methods
White Box Testing Limitation
Specification: inputs an integer param and returns half of its
value if even, its value otherwise
Example:
1 . v o i d f u n ( i n t param ) {
2. int result ;
3. r e s u l t =param / 2 ;
4. return result ;
5. }
Limitation
It doesn’t reveal errors due to missing paths
Quality Assurance and Software Testing
Seven Testing Principles
Seven Testing Principles
1 Testing shows presence of defects
2 Exhaustive testing is impossible
3 Early testing
4 Defect clustering
5 Pesticide paradox
6 Testing is context dependent
7 Absence of errors fallacy
Quality Assurance and Software Testing
Stages of Testing
Stages of Testing
Test Planning
Analysis and Design
Implementation and Execution
Evaluating exit criteria and Reporting
Test Closure activities
Quality Assurance and Software Testing
Stages of Testing
Test Planning Activities
Test Planning Activities
Defining the Scope of Project
Determine Test Approach
Defining Test Strategy
Determine Test Resources
Define Exit Criteria
Quality Assurance and Software Testing
Stages of Testing
Analysis and Design
Analysis and Design
Analysis of Business requirements
Designing Test Scenarios
Creating Test Data
Designing Testcases based on Scenarios
Test Environment Setup
Quality Assurance and Software Testing
Stages of Testing
Implementation and Execution
Analysis and Design
Executing the Testcases in givenTimeline
Prioritizing the Testcases
Writing Automation scripts if necessary
Defect Logging and Tracking
Test Case Status Reporting
Quality Assurance and Software Testing
Stages of Testing
Evaluating exit criteria and Reporting
Evaluating exit criteria and Reporting
To check the test Status against the exit criteria specified in
test planning.
To assess if more test are needed or if the exit criteria
specified should be changed.
To write a test summary report for stakeholders.
Quality Assurance and Software Testing
Stages of Testing
Test Closure activities
Evaluating exit criteria and Reporting
To finalize and archive testware such as scripts, test
environments, etc. for later reuse.
To handover the testware to the maintenance organization.
They will give support to the software.
To evaluate how the testing went and learn lessons for future
releases and projects.
Quality Assurance and Software Testing
Testing Methodologies
Testing Methodologies
Waterfall model
Iterative Model
Agile
Quality Assurance and Software Testing
Testing Methodologies
Verification and Validation
Verification and validation VandV
check during development if the product:
Meets its specifications
Delivers the functionality expected by the people paying for
this product
Quality Assurance and Software Testing
Testing Methodologies
Verification and Validation
The classical V model
Quality Assurance and Software Testing
Testing Methodologies
Verification and Validation
Verification
evaluates a component or system to determine whether the
products of a given development phase satisfy the conditions
imposed at the start of each phase
Are we building the system right?
Quality Assurance and Software Testing
Testing Methodologies
Verification and Validation
Validation
Process of evaluating a system or component during or at the
end of development process to determine whether it satisfies
specified requirements
Are we building the right system?
Quality Assurance and Software Testing
Defect Life Cycle
Defect Life Cycle
Quality Assurance and Software Testing
Defect Life Cycle
Defect Life Cycle
New: QA raised the Defect -
Open : Test Manager/Developer changes the status
Assigned – Developer – he will work on it
Fixed- 26 th febraury Build
Verification : Once you verify – Closed
Quality Assurance and Software Testing
Defect Life Cycle
Defect Life Cycle
New: QA raised the Defect -
Open : Test Manager/Developer changes the status
Assigned – Developer – he will work on it
Fixed- 26th February Build
Verification : Once you verify
Closed
Quality Assurance and Software Testing
Defect Life Cycle
Defect Template
Description:
Steps to Reproduce:
Test Data:
Expected Result:
Action Result:
Screen shot:
Time stamp:
Assigned to:
Severity :
Priority :
Quality Assurance and Software Testing
Defect Life Cycle
Defect Template Example
Description: Password reset happening after
clicking on cancel
Steps to Reproduce: login till clicking on cancel
Test Data: user id , password
Expected Result: Password reset should not hap-
pen
Action Result: Password reset is happening
Screen shot: image or video
Time stamp:
Assigned to: Test Manager/Developer
Severity : low medium high
Priority : high
