Black box testing

What is Black box testing?

What is Black box testing?

Test design technique of Black Box

Levels Applicable To Black-box testing

Syntax Drive Testing

Equivalence partitioning

What are the Advantages of black-box testing?

What are the Disadvantages of black-box testing?


Black box testing



What is Black box testing?

This testing is also called BEHAVIOURAL TESTING. It is a method of testing software. In this methodology, the internal structure or design, or implementation of the item being tested is not known to the tester. These tests can be functional as well as non-functional. Most of the times these tests are functional.

This method is called black-box testing because the software program is like a black box in front of the tester. The tester cannot see inside the software. This method attempts to find errors in the categories, given below.

  • Interface error
  • Incorrect functions.
  • Missing functions.
  • Errors in a data structure.
  • Errors in external database access.
  • Behavior/performance error.
  • Initialization errors.
  • Termination errors.

Test design technique: Black Box

Select the test cases based on an analysis of the specification of a system without a referee to its internal structure. The specification includes specifying the test is functional or non-functional.

Equivalence Partitioning:

In this technique, the input values are divided into valid and invalid partitions as test data.

Boundary value analysis:

In this technique checking of boundaries for input, values are tested. After that selecting values. We test that boundaries with inside or outside of the boundaries as test data.

Cause-Effect Graphing:

It is a software test design technique in which the cases and effects are identified, producing the cause-effect graph and generating test cases accordingly.


what is Black box testing

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Levels Applicable To: Black-box testing

Black box testing is applicable for the following levels:

  1. Integration testing
  2. System testing
  3. Acceptance testing

If the level is higher and bigger, the box will be more complex. This is the reason the more black-box testing method comes into use.

Black Box Testing: Software engineering

In terms of software engineering, black box testing is a type of software testing. In this testing method, the functionality of the function is not known. All the testing is performed without the internal knowledge of the products. This testing can be performed in the following ways:

Syntax Drive Testing:

This testing is applied to the system that can be syntactically represented via context-free grammar. That is why the test cases are generated and each grammar rule is used at least once.

Equivalence partitioning:

There are many types of inputs that work similarly. Instead of giving them all one by one we can group them together and test only one input of each group. This idea is to partition the input domain of the system into a number of squalene classes.

For example, each group/class works in a similar way. If a test case in any one group/class results in some error, other members of the class would also result in the same error.

The technique involves the following two steps:

  1. Identification of Equivalence class

In this step, we can partition any input domain into a minimum of two sets. These sets will be valid values and invalid values. Such as if the valid range is 0 to 101. We can select one valid input like 45 and one invalid input like 107.

  1. Generating test cases

We assign unique identification numbers to each valid and invalid class of input. And write a test case covering all valid and invalid test cases. It is very important to consider that no two invalid inputs should mask each other.


Advantages of black-box testing

  • It is well suited for large scale systems.
  • It is very efficient for large scale segments.
  • It needs no access code.
  • It is easy to understand.
  • It is easy to understand for beginners.
  • Testers can test the application without the knowledge of implementation etc.
  • Its penetration testing speed is high.
  • It is possible to get a cheaper price.
  • It is easy to find errors.
  • Black box testing requires few resources.

Disadvantages of black-box testing

Now you can read disadvantages of testing

  • It is not possible to see inside the software.
  • Test cases are difficult to design.
  • A small number of possible inputs can be tested easily only.
  • There can be the unnecessary repetition of test inputs if the tester knows not about the last case.
  • It may leave many program paths untested.
  • It cannot be directed toward a specific segment.
  • It is not possible to test the quality of coding.
  • Impossibility of its strict adherence to the coding standards.


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