Performance Testing - Load testing
Load testing: is subjecting a system to a statistically representative (usually) load. The two main reasons for using such loads is in support of software reliability testing and in performance testing. The term "load testing" by itself is too vague and imprecise to warrant use. For example, do you mean representative load," "overload," "high load," etc. In performance testing, load is varied from a minimum (zero) to the maximum level the systemcan sustain without running out of resources or having, transactions suffer (application-specific) excessive delay.
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about software testing.
http://www.crestech.in
http://www.crestechsoftware.com.au
Monday, June 29, 2009
Integration Testing
Integration Testing
One of the most difficult aspects of software development is the integration and testing of large, untested sub-systems. The integrated system frequently fails in significant and mysterious ways, and it is difficult to fix it
Integration testing exercises several units that have been combined to form a module, subsystem, or system. Integration testing focuses on the interfaces between units, to make sure the units work together. The nature of this phase is certainly 'white box', as we must have a certain knowledge of the units to recognize if we have been successful in fusing them together in the module.
There are three main approaches to integration testing: top-down, bottom-up and 'big bang'. Top-down combines, tests, and debugs top-level routines that become the test 'harness' or 'scaffolding' for lower-level units. Bottom-up combines and tests low-level units into progressively larger modules and subsystems. 'Big bang' testing is, unfortunately, the prevalent integration test 'method'. This is waiting for all the module units to be complete before trying them out together.
Integration tests can rely heavily on stubs or drivers. Stubs stand-in for finished subroutines or sub-systems. A stub might consist of a function header with no body, or it may read and return test data from a file, return hard-coded values, or obtain data from the tester. Stub creation can be a time consuming piece of testing.
The cost of drivers and stubs in the top-down and bottom-up testing methods is what drives the use of 'big bang' testing. This approach waits for all the modules to be constructed and tested independently, and when they are finished, they are integrated all at once. While this approach is very quick, it frequently reveals more defects than the other methods. These errors have to be fixed and as we have seen, errors that are found 'later' take longer to fix. In addition, like bottom up, there is really nothing that can be demonstrated until later in the process.
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about software testing.
http://www.crestech.in
http://www.crestechsoftware.com.au
One of the most difficult aspects of software development is the integration and testing of large, untested sub-systems. The integrated system frequently fails in significant and mysterious ways, and it is difficult to fix it
Integration testing exercises several units that have been combined to form a module, subsystem, or system. Integration testing focuses on the interfaces between units, to make sure the units work together. The nature of this phase is certainly 'white box', as we must have a certain knowledge of the units to recognize if we have been successful in fusing them together in the module.
There are three main approaches to integration testing: top-down, bottom-up and 'big bang'. Top-down combines, tests, and debugs top-level routines that become the test 'harness' or 'scaffolding' for lower-level units. Bottom-up combines and tests low-level units into progressively larger modules and subsystems. 'Big bang' testing is, unfortunately, the prevalent integration test 'method'. This is waiting for all the module units to be complete before trying them out together.
Integration tests can rely heavily on stubs or drivers. Stubs stand-in for finished subroutines or sub-systems. A stub might consist of a function header with no body, or it may read and return test data from a file, return hard-coded values, or obtain data from the tester. Stub creation can be a time consuming piece of testing.
The cost of drivers and stubs in the top-down and bottom-up testing methods is what drives the use of 'big bang' testing. This approach waits for all the modules to be constructed and tested independently, and when they are finished, they are integrated all at once. While this approach is very quick, it frequently reveals more defects than the other methods. These errors have to be fixed and as we have seen, errors that are found 'later' take longer to fix. In addition, like bottom up, there is really nothing that can be demonstrated until later in the process.
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about software testing.
http://www.crestech.in
http://www.crestechsoftware.com.au
Functional testing
Functional testing
Functional testing: Application of test data derived from the specified functional requirements without regard to the final program structure. Also known as black-box testing.
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about software testing.
http://www.crestech.in
http://www.crestechsoftware.com.au
Functional testing: Application of test data derived from the specified functional requirements without regard to the final program structure. Also known as black-box testing.
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about software testing.
http://www.crestech.in
http://www.crestechsoftware.com.au
Exploratory Testing
Exploratory Testing
An interactive process of concurrent product exploration, test
design, and test execution. The heart of exploratory testing can be
stated simply: The outcome of this test influences the design of the
next test.
The plainest definition of exploratory testing is test design and
test execution at the same time. This is the opposite of scripted
testing (predefined test procedures, whether manual or automated).
Exploratory tests, unlike scripted tests, are not defined in advance
and carried out precisely according to plan. This may sound like a
straightforward distinction, but in practice it's murky. That's
because "defined" is a spectrum. Even an otherwise elaborately
defined test procedure will leave many interesting details (such as
how quickly to type on the keyboard, or what kinds of behavior to
recognize as a failure) to the discretion of the tester. Likewise,
even a free-form exploratory test session will involve tacit
constraints or mandates about what parts of the product to test, or
what strategies to use. A good exploratory tester will write down
test ideas and use them in later test cycles. Such notes sometimes
look a lot like test scripts, even if they aren't. Exploratory
testing is sometimes confused with "ad hoc" testing. Ad hoc testing
normally refers to a process of improvised, impromptu bug searching.
By definition, anyone can do ad hoc testing
What kinds of specifics affect ET? Here are some of them:
1. the mission of the test project
2. the mission of this particular test session
3. the role of the tester
4. the tester (skills, talents, and preferences)
5. available tools and facilities
6. available time
7. available test data and materials
8. available help from other people
9. accountability requirements
10. what the tester‘s clients care about
11. the current testing strategy
12. the status of other testing efforts on the same product
13. the product, itself- its user interface - its behavior - its
present state of execution - its defects- its testability- its
purpose
14. what the tester knows about the product- what just happened in
the previous test - known problems with it- past problems with it -
strengths and weaknesses - risk areas and magnitude of perceived risk
- recent changes to it - direct observations of it- rumors about it -
the nature of its users and user behavior - how it‘s supposed to work
- how it‘s put together - how it‘s similar to or different from other
products
15. what the tester would like to know about the product
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about
software testing.
http://www.crestech.in
href="http://www.crestechsoftware.com.au">http://www.crestechsoftware
.com.au
An interactive process of concurrent product exploration, test
design, and test execution. The heart of exploratory testing can be
stated simply: The outcome of this test influences the design of the
next test.
The plainest definition of exploratory testing is test design and
test execution at the same time. This is the opposite of scripted
testing (predefined test procedures, whether manual or automated).
Exploratory tests, unlike scripted tests, are not defined in advance
and carried out precisely according to plan. This may sound like a
straightforward distinction, but in practice it's murky. That's
because "defined" is a spectrum. Even an otherwise elaborately
defined test procedure will leave many interesting details (such as
how quickly to type on the keyboard, or what kinds of behavior to
recognize as a failure) to the discretion of the tester. Likewise,
even a free-form exploratory test session will involve tacit
constraints or mandates about what parts of the product to test, or
what strategies to use. A good exploratory tester will write down
test ideas and use them in later test cycles. Such notes sometimes
look a lot like test scripts, even if they aren't. Exploratory
testing is sometimes confused with "ad hoc" testing. Ad hoc testing
normally refers to a process of improvised, impromptu bug searching.
By definition, anyone can do ad hoc testing
What kinds of specifics affect ET? Here are some of them:
1. the mission of the test project
2. the mission of this particular test session
3. the role of the tester
4. the tester (skills, talents, and preferences)
5. available tools and facilities
6. available time
7. available test data and materials
8. available help from other people
9. accountability requirements
10. what the tester‘s clients care about
11. the current testing strategy
12. the status of other testing efforts on the same product
13. the product, itself- its user interface - its behavior - its
present state of execution - its defects- its testability- its
purpose
14. what the tester knows about the product- what just happened in
the previous test - known problems with it- past problems with it -
strengths and weaknesses - risk areas and magnitude of perceived risk
- recent changes to it - direct observations of it- rumors about it -
the nature of its users and user behavior - how it‘s supposed to work
- how it‘s put together - how it‘s similar to or different from other
products
15. what the tester would like to know about the product
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about
software testing.
http://www.crestech.in
href="http://www.crestechsoftware.com.au">http://www.crestechsoftware
.com.au
Boundary Value Analysis
Boundary Value Analysis
Large number of errors tend to occur at boundaries of the input domain.
BVA leads to selection of test cases that exercise boundary values.
BVA complements equivalence partitioning. Rather than select any element in an equivalence class, select those at the ''edge' of the class.
Examples:
For a range of values bounded by a and b, test (a-1), a, (a+1), (b-1), b, (b+1).
If input conditions specify a number of values n, test with (n-1), n and (n+1) input values.
Apply 1 and 2 to output conditions (e.g., generate table of minimum and maximum size).
If internal program data structures have boundaries (e.g., buffer size, table limits), use input data to exercise structures on boundaries.
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about software testing.
http://www.crestech.in
http://www.crestechsoftware.com.au
Large number of errors tend to occur at boundaries of the input domain.
BVA leads to selection of test cases that exercise boundary values.
BVA complements equivalence partitioning. Rather than select any element in an equivalence class, select those at the ''edge' of the class.
Examples:
For a range of values bounded by a and b, test (a-1), a, (a+1), (b-1), b, (b+1).
If input conditions specify a number of values n, test with (n-1), n and (n+1) input values.
Apply 1 and 2 to output conditions (e.g., generate table of minimum and maximum size).
If internal program data structures have boundaries (e.g., buffer size, table limits), use input data to exercise structures on boundaries.
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about software testing.
http://www.crestech.in
http://www.crestechsoftware.com.au
About Software Testing
About Software Testing
Process of evaluation of Software application: To verify it satisfy the specified requirements With intent to find errors To Check if the system ?Fit for Purpose? Simulation of real time scenarios.
Testing is not a one-time activity—applications need to be tested throughout their lifecycle. Every version upgrade, module addition, or enhancement, as well as every implementation at a new site or increase in user load, needs to be put through comprehensive testing. The Program Doesn‘t Work Nobody would pay you to test if their program didn‘t have bugs. All programs have bugs. Any change to a program can cause new bugs, and any aspect of the program can be broken. You DON‘T ?verify that the program is working.? You FIND bugs. “If you set your mind to show that a program works correctly, you’ll be more likely to miss problems than if you want and expect the program to fail.” Complete Testing is Impossible:
1. There are a nearly infinite number of paths through any non-trivial program.
2. There are a virtually infinite set of combinations of data that you can feed the program.
You can’t test them all.
1. Therefore, your task is to find bugs --not to find all the bugs.
2. You want to find as many bugs as possible
3. Find the most serious bugs
4. Find bugs as early as possible
5. Your challenges will require judgment, trade-offs, and efficiency.
“Q: How many QA testers does it take to change a lightbulb?
A: QA testers don't change anything. They just report that it's dark.” Kerry Zallar?
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about software testing.
http://www.crestech.in
http://www.crestechsoftware.com.au
Process of evaluation of Software application: To verify it satisfy the specified requirements With intent to find errors To Check if the system ?Fit for Purpose? Simulation of real time scenarios.
Testing is not a one-time activity—applications need to be tested throughout their lifecycle. Every version upgrade, module addition, or enhancement, as well as every implementation at a new site or increase in user load, needs to be put through comprehensive testing. The Program Doesn‘t Work Nobody would pay you to test if their program didn‘t have bugs. All programs have bugs. Any change to a program can cause new bugs, and any aspect of the program can be broken. You DON‘T ?verify that the program is working.? You FIND bugs. “If you set your mind to show that a program works correctly, you’ll be more likely to miss problems than if you want and expect the program to fail.” Complete Testing is Impossible:
1. There are a nearly infinite number of paths through any non-trivial program.
2. There are a virtually infinite set of combinations of data that you can feed the program.
You can’t test them all.
1. Therefore, your task is to find bugs --not to find all the bugs.
2. You want to find as many bugs as possible
3. Find the most serious bugs
4. Find bugs as early as possible
5. Your challenges will require judgment, trade-offs, and efficiency.
“Q: How many QA testers does it take to change a lightbulb?
A: QA testers don't change anything. They just report that it's dark.” Kerry Zallar?
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about software testing.
http://www.crestech.in
http://www.crestechsoftware.com.au
Performance Testing - Stress testing 2
Performance Testing - Stress testing 2
Stress testing :is subjecting a system to an unreasonable load while
denying it the resources (e.g., RAM, disc, mips, interrupts, etc.)
needed to process that load. The idea is to stress a system to the
breaking point in order to find bugs that will make that break
potentially harmful. The system is not expected to process the
overload without adequate resources, but to behave (e.g., fail) in a
decent manner (e.g., not corrupting or losing data). Bugs and failure
modes discovered under stress testing may or may not be repaired
depending on the application, the failure mode, consequences, etc.
The load (incoming transaction stream) in stress testing is often
deliberately distorted so as to force the system into resource
depletion.
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about
software testing.
http://www.crestech.in
href="http://www.crestechsoftware.com.au">http://www.crestechsoftware
.com.au
Stress testing :is subjecting a system to an unreasonable load while
denying it the resources (e.g., RAM, disc, mips, interrupts, etc.)
needed to process that load. The idea is to stress a system to the
breaking point in order to find bugs that will make that break
potentially harmful. The system is not expected to process the
overload without adequate resources, but to behave (e.g., fail) in a
decent manner (e.g., not corrupting or losing data). Bugs and failure
modes discovered under stress testing may or may not be repaired
depending on the application, the failure mode, consequences, etc.
The load (incoming transaction stream) in stress testing is often
deliberately distorted so as to force the system into resource
depletion.
Software Testing Training
http://www.qacampus.com
QACampus is Center of Education for anything and everything about
software testing.
http://www.crestech.in
href="http://www.crestechsoftware.com.au">http://www.crestechsoftware
.com.au
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