Unit 1: Basics of Software Testing and Testing Methods
CO1 : Apply various software testing methods
Software testing:
Software testing is defined as performing Verification and Validation of the Software
Product for its correctness and accuracy of working.
Software Testing is the process of executing a program with the intent of finding errors.
A successful test is one that uncovers an as-yet-undiscovered error.
Testing can show the presence of bugs but never their absence.
Testing is a support function that helps developers look good by finding their mistakes
before anyone else does.
Role of testing / Objectives of testing:
1. Finding defects which may get created by the programmer while developing the software.
2. Gaining confidence in and providing information about the level of quality.
3. To prevent defects.
4. To make sure that the end result meets the business and user requirements.
5. To ensure that it satisfies the BRS that is Business Requirement Specification and SRS that is
System Requirement Specifications.
6. To gain the confidence of the customers by providing them a quality product
What is Software testing?
• Finding defects
• Trying to break the system
• Finding and reporting defects
• Demonstrating correct functionality
• Demonstrating incorrect functionality
• Demonstrating robustness, reliability, security, maintainability, …
• Measuring performance, reliability, …
• Evaluating and measuring quality
• Proving the software correct
• Executing pre-defined test cases
• Automatic error detection
Skills Required for Tester
• Communication skills
• Domain knowledge
• Desire to learn
• Technical skills
• Analytical skills
• Planning
• Integrity
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, Unit 1: Basics of Software Testing and Testing Methods
• Curiosity
• Think from users perspective
• Be a good judge of your product
Bug, Fault & Failure
• A person makes an Error
• That creates a fault in software
• That can cause a failure in operation
• Error: An error is a human action that produces the incorrect result that results
in a fault.
• Bug: The presence of error at the time of execution of the software.
• Fault: State of software caused by an error.
• Failure: Deviation of the software from its expected result. It is an event.
• Defect: A defect is an error or a bug, in the application which is created. A programmer
while designing and building the software can make mistakes or error. These mistakes or
errors mean that there are flaws in the software. These are called defects.
Why do defects occur in software?
Software is written by human beings
Who know something, but not everything
Who have skills, but aren’t perfect
Who don’t usually use rigorous methods
Who do make mistakes (errors)
Under increasing pressure to deliver to strict deadlines
No time to check, assumptions may be wrong
Systems may be incomplete
Software is complex, abstract and invisible
Hard to understand
Hard to see if it is complete or working correctly
No one person can fully understand large systems
Numerous external interfaces and dependencies
Sources of defects
Education
Developers does not understand well enough what he or she is doing
Lack of proper education leads to errors in specification, design, coding, and testing
Communication
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, Unit 1: Basics of Software Testing and Testing Methods
Developers do not know enough
Information does not reach all stakeholders
Information is lost
Oversight
Omitting to do necessary things
Transcription
Developer knows what to do but simply makes a mistake
Process
Process is not applicable for the actual situation
Process places restrictions that cause errors
Test Plan
A test plan is a systematic approach to testing a system i.e. software. The plan typically
contains a detailed understanding of what the eventual testing workflow will be.
Test Case
A test case is a specific procedure of testing a particular requirement.
It will include:
• Identification of specific requirement tested
• Test case success/failure criteria
• Specific steps to execute test
• Test Data
Entry and Exit Criteria for software testing
Process model is a way to represent any given phase of software development that prevent and
minimize the delay between defect injection and defect detection/ correction.
Entry criteria, specifies when that phase can be started also included the inputs for the phase.
Tasks or steps that need to be carried out in that phase along with measurements that characterize
the tasks. Verification, which specifies methods of checking that tasks have been carried out
correctly. Clear entry criteria make sure that a given phase does not start prematurely. The
verification for each phase helps to prevent defects. At least defects can be minimized.
Exit criteria, which stipulate the conditions under which one can consider the phases as done and
included are the outputs for the phase.
Exit criteria may include:
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CO1 : Apply various software testing methods
Software testing:
Software testing is defined as performing Verification and Validation of the Software
Product for its correctness and accuracy of working.
Software Testing is the process of executing a program with the intent of finding errors.
A successful test is one that uncovers an as-yet-undiscovered error.
Testing can show the presence of bugs but never their absence.
Testing is a support function that helps developers look good by finding their mistakes
before anyone else does.
Role of testing / Objectives of testing:
1. Finding defects which may get created by the programmer while developing the software.
2. Gaining confidence in and providing information about the level of quality.
3. To prevent defects.
4. To make sure that the end result meets the business and user requirements.
5. To ensure that it satisfies the BRS that is Business Requirement Specification and SRS that is
System Requirement Specifications.
6. To gain the confidence of the customers by providing them a quality product
What is Software testing?
• Finding defects
• Trying to break the system
• Finding and reporting defects
• Demonstrating correct functionality
• Demonstrating incorrect functionality
• Demonstrating robustness, reliability, security, maintainability, …
• Measuring performance, reliability, …
• Evaluating and measuring quality
• Proving the software correct
• Executing pre-defined test cases
• Automatic error detection
Skills Required for Tester
• Communication skills
• Domain knowledge
• Desire to learn
• Technical skills
• Analytical skills
• Planning
• Integrity
Page 1
, Unit 1: Basics of Software Testing and Testing Methods
• Curiosity
• Think from users perspective
• Be a good judge of your product
Bug, Fault & Failure
• A person makes an Error
• That creates a fault in software
• That can cause a failure in operation
• Error: An error is a human action that produces the incorrect result that results
in a fault.
• Bug: The presence of error at the time of execution of the software.
• Fault: State of software caused by an error.
• Failure: Deviation of the software from its expected result. It is an event.
• Defect: A defect is an error or a bug, in the application which is created. A programmer
while designing and building the software can make mistakes or error. These mistakes or
errors mean that there are flaws in the software. These are called defects.
Why do defects occur in software?
Software is written by human beings
Who know something, but not everything
Who have skills, but aren’t perfect
Who don’t usually use rigorous methods
Who do make mistakes (errors)
Under increasing pressure to deliver to strict deadlines
No time to check, assumptions may be wrong
Systems may be incomplete
Software is complex, abstract and invisible
Hard to understand
Hard to see if it is complete or working correctly
No one person can fully understand large systems
Numerous external interfaces and dependencies
Sources of defects
Education
Developers does not understand well enough what he or she is doing
Lack of proper education leads to errors in specification, design, coding, and testing
Communication
Page 2
, Unit 1: Basics of Software Testing and Testing Methods
Developers do not know enough
Information does not reach all stakeholders
Information is lost
Oversight
Omitting to do necessary things
Transcription
Developer knows what to do but simply makes a mistake
Process
Process is not applicable for the actual situation
Process places restrictions that cause errors
Test Plan
A test plan is a systematic approach to testing a system i.e. software. The plan typically
contains a detailed understanding of what the eventual testing workflow will be.
Test Case
A test case is a specific procedure of testing a particular requirement.
It will include:
• Identification of specific requirement tested
• Test case success/failure criteria
• Specific steps to execute test
• Test Data
Entry and Exit Criteria for software testing
Process model is a way to represent any given phase of software development that prevent and
minimize the delay between defect injection and defect detection/ correction.
Entry criteria, specifies when that phase can be started also included the inputs for the phase.
Tasks or steps that need to be carried out in that phase along with measurements that characterize
the tasks. Verification, which specifies methods of checking that tasks have been carried out
correctly. Clear entry criteria make sure that a given phase does not start prematurely. The
verification for each phase helps to prevent defects. At least defects can be minimized.
Exit criteria, which stipulate the conditions under which one can consider the phases as done and
included are the outputs for the phase.
Exit criteria may include:
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