Overview:
In the world of technology, Functional testing is a very essential part of every software product when it comes to delivering Quality to the End-Users. Verifying the functionality against the Requirement Specifications is termed as Black Box Testing where the main concern is about to test the behavior of software, unlike White Box Testing which involves testing of source code that is usually done at the unit level.
Black Box Testing is also known as opaque, functional or behavioral-based testing which can be applied to every level of testing, such as Unit, Integration, System and User Acceptance Testing. Unlike white box testing, it requires no programming skills as the Test Engineers Validates the software functionality without looking into the internal code structure. Click here to get a detail view of Verification & Validation.
In this blog, we will highlight some major techniques of Black Box Testing:
Equivalence Class Partitioning:
In equivalence partitioning, input values are divided into certain groups that are expected to exhibit similar behavior. Each and every condition in the particular partition works as same as others. Moreover, it reduces the number of test cases from infinite to finite and is applicable to all the levels of testing.
For example:
Suppose, we are creating an account Opencart Site,
so it asks for multiple information, such as First Name, Last Name, Contact number, etc.
Let’s assume it takes Contact Number as one of the fields which accept 10 digits number only. So we can partition it into valid(10 digits) ie: 9876543210 & invalid(9&11 digits) ie: 987654321 and 98765432100.
Boundary Value Analysis(BVA):
In this technique, we analyze the boundaries of valid and invalid partitions, as the edge of each equivalence partitions is more likely to throw invalid output than the values within the partitions. Every partition has its maximum and minimum values & these values are set as its boundaries. BVA is also applicable to all levels of testing.
For example:
Taking the above example into consideration, assume the First Name accepts 6-18 characters only.
Analyze the boundaries ie:
- min-1 = 5(Invalid Input)
- max+1 = 19(Invalid Input)
- >5 to <19 (Valid Input)
Thus, Minimum boundary value is 6
- Maximum boundary value is 18
- Valid input values are (6,10,14,18)
- Invalid input values are 5 & 19
Decision Table:
This design technique is also known as Cause-Effect Table. It is more likely to work on functionalities which has the if-else logical relationship between inputs. Here, we analyze inputs as conditions & output as some actions.
For Example:
As per different test cases results, we can maintain the Decision Table like this:
State Transition:
Using State Transition technique, we analyze the sequence of transition and state or events by applying the same input. The whole set of test cases will have the traversal of the expected output values and all states.
For example:
It is so obvious that when we logged in, we are redirected to the Home page which also means that we have entered username & password correctly. Just imagine, what will happen if login credentials are invalid. Nothing much but we’ll get few more attempts to log-in.
Suppose, we have only 3 attempts & we have failed in the previous 2 attempts then, it will give warning message ”Incorrect username & password”.
Or else a google re-captcha will appear, for security reason after you have failed in all the 3 attempts.
That’s all about Black Box Testing.