I have covered what is White box Testing in previous article. Here I will concentrate on Black box testing. BBT advantages, disadvantages and and How Black box testing is performed i.e the black box testing techniques.
Black box testing treats the system as a “black-box”, so it doesn’t explicitly use Knowledge of the internal structure or code. Or in other words the Test engineer need not know the internal working of the “Black box” or application.
Main focus in black box testing is on functionality of the system as a whole. The term ‘behavioral testing’ is also used for black box testing and white box testing is also sometimes called ’structural testing’. Behavioral test design is slightly different from black-box test design because the use of internal knowledge isn’t strictly forbidden, but it’s still discouraged.
Each testing method has its own advantages and disadvantages. There are some bugs that cannot be found using only black box or only white box. Majority of the applicationa are tested by black box testing method. We need to cover majority of test cases so that most of the bugs will get discovered by blackbox testing.
Black box testing occurs throughout the software development and Testing life cycle i.e in Unit, Integration, System, Acceptance and regression testing stages.
Tools used for Black Box testing:
Black box testing tools are mainly record and playback tools. These tools are used for regression testing that to check whether new build has created any bug in previous working application functionality. These record and playback tools records test cases in the form of some scripts like TSL, VB script, Java script, Perl.
Advantages of Black Box Testing
- Tester can be non-technical.
- Used to verify contradictions in actual system and the specifications.
- Test cases can be designed as soon as the functional specifications are complete
Disadvantages of Black Box Testing
- The test inputs needs to be from large sample space.
- It is difficult to identify all possible inputs in limited testing time. So writing test cases is slow and difficult
- Chances of having unidentified paths during this testing
Methods of Black box Testing:
Graph Based Testing Methods:
Each and every application is build up of some objects. All such objects are identified and graph is prepared. From this object graph each object relationship is identified and test cases written accordingly to discover the errors.
Error Guessing:
This is purely based on previous experience and judgment of tester. Error Guessing is the art of guessing where errors can be hidden. For this technique there are no specific tools, writing the test cases that cover all the application paths.
Boundary Value Analysis:
Many systems have tendency to fail on boundary. So testing boundry values of application is important. Boundary Value Analysis (BVA) is a test Functional Testing technique where the extreme boundary values are chosen. Boundary values include maximum, minimum, just inside/outside boundaries, typical values, and error values.
Extends equivalence partitioning
Test both sides of each boundary
Look at output boundaries for test cases too
Test min, min-1, max, max+1, typical values
BVA techniques:
1. Number of variables
For n variables: BVA yields 4n + 1 test cases.
2. Kinds of ranges
Generalizing ranges depends on the nature or type of variables
Advantages of Boundary Value Analysis
1. Robustness Testing - Boundary Value Analysis plus values that go beyond the limits
2. Min - 1, Min, Min +1, Nom, Max -1, Max, Max +1
3. Forces attention to exception handling
Limitations of Boundary Value Analysis
Boundary value testing is efficient only for variables of fixed values i.e boundary.
Equivalence Partitioning:
Equivalence partitioning is a black box testing method that divides the input domain of a program into classes of data from which test cases can be derived.
How is this partitioning performed while testing:
1. If an input condition specifies a range, one valid and one two invalid classes are defined.
2. If an input condition requires a specific value, one valid and two invalid equivalence classes are defined.
3. If an input condition specifies a member of a set, one valid and one invalid equivalence class is defined.
4. If an input condition is Boolean, one valid and one invalid class is defined.
Comparison Testing:
Different independent versions of same software are used to compare to each other for testing in this method.
Reference- http://www.softrel.org/stgb.html
36 comments ↓
it was good and valuable information about the basics of BBT.
Thanks Namita
Actually you could have observed that most of the testers in India are Black box testers. There is need to give more emphasis on this topic. So I will keep writing some more topics on Black box testing and practical methods.
Need to know about the check list cases
Really ! You have very good skill of representing this !
I want to read more and more about testing through this blog….
Thanks
its really good to know the basics in blackbox testing..thanks.please do emphasize on templates.
Comments are Excellent . I love to see such many and More Comments.
Thanks
Shridhar
can u provide me with blackbox testing interview questions?
dear all,
can u tell me what is a build? when it is started ?
bye
raj
can we test the application without having any system this question was asked in interview.And also how to generate the reports.pls suggests me
regards
raj
Priya, i will send u notes about the check list cases if u leave ur mail id and Phone no
what is prototype testing?
What is white box testing ?
White box testing is based on knowledge of the internal logic of an application’s code. Also known as Glass box Testing. Internal software and code working should be known for this type of testing. Tests are based on coverage of code statements, branches, paths, conditions.
what do u mean by framework?
wat do u mean by checklists in testing?
Hi Vijay
Recently I came across the foll. terms:
Grey Box testing
Red Box testing
Yellow Box testing &
Green Box testing
Could u pls explain the above types of testing in detail. Thanks.
hi vijay
plz tell something more about black box testing
thanks
1.What is the Difference Between Test Cases and Test Scenarios????????
2. Canu plz tell me the exacr definition of Test Scenario??
hi Rajani,
a prototype testing is a sample application without Functionality.
hi sivaguru,
test Scenario specifies required test conditions to apply on a build.
where as test case specifies detailed procedure to apply the test conditions on a build.
This is the best answer that i can give…….
Hi all,
Any sample testcases for implementing the “Graphs based testing Methods???
Articles and comments brings me often to this site.
great.
plz send me links of technical papers on black box testing if anybody know before sunday my email address is
abhasgoyal@gmail.com
I want to learn about test cases and how to write testcases for database testing and system testing
what is Posittive test case & negetive test case?
hello to everyone, i want to know the basic concepts of testing tools in brief individually, can u people let me know from where can i get this information
thank u
whaT IS SMOKE TESTING , SANITY TESTING
How we can plot a graph between test conditions and test cases in black-box testing?
@ varsha, bala
“”Red Box testing
Yellow Box testing &
Green Box testing”",
there is no terminology like this in testing industry, some can say it is protocol testing-redbox, or error message testing-red box, warning message testing-yellow box and green box- environmental testing, of cource white, black, grey box testing is there. Or else why it is called by red, green, yellow box testing, anyway it is not due to the icon\symbol present in the warning or error messages.
Vijay
hey guys, trull i learn a lot from u. …thanks
Can anyone explain to be more in details. wat is error guessing?
thankx
It is a nice presentation as well as very simple to understand.
please, keep on upgrading.
Hi,
I want to know what exactly do the term exhaustive testing ? IS it possible to carry it out ?
Thanks,
Rashmi
hey guys, trully i learnt a lot from u. …thanks
Can anyone explain more in details. ….. Tools in Black Box Testing
can any body explain testing tools in black box testing
wat abt comparison of different testing technique??
Iam a fresher in testing field. Now I’m testing a web based application. I want to know what all procedures( in WBT & BBT) I hav to do for a successful test.
Mail ID: Tammukchowdary@gmail.com
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