Black box Test (i)

Black box Test (i)

1.1 What is a black box test

Black box testing is also called functional testing (functional testing), because in black-box testing, the main focus is on the functionality of the software being tested, not the internal logic. Black-Box testing is a test concept that is very different from white-box testing and is one of the earliest and most widely used tests in software testing. In the black box test, the internal structure of the object being measured, the operation of the test personnel is not visible, testers of the tested product is mainly based on its specifications, verify its consistency with the specifications. Like a vending machine, in order to verify that it can sell the goods automatically, you can specify the items you want to buy, plug in the coins, and then observe if the vending machine can output the correct goods and find the correct change. In this process you do not need to focus on how the vending machine determines the amount of money, how to choose the goods, how to find the internal operation of change. This is the scope of the white box test, and the black box test focuses on the results. Figure 1-1 is one of the black box tests.

Figure 1-1 Black Box test

The black box test attempts to discover the following types of errors:

1) function error or omission;

2) interface error;

3) data structure or external database access error;

4) Performance error;

5) initialization and termination errors.

1.2 Why the Black box test

Now that we've done a white-box test, why do we have to do black-box testing? Isn't that a waste of work?

White-Box testing was adopted early in the test, while black-box testing was used primarily for later testing. The black box test intentionally does not consider the control structure, but the attention information domain. Black-Box testing is not a substitute for white-box testing, but is used to assist white-box testing to find other types of errors. The black box test is used to answer the following questions:

• • How to test the effectiveness of a feature?
  • What type of input produces good test cases?
  • Is the system particularly sensitive to specific input values?
  • How do I delimit the bounds of a data class?
  • What data rates and data volumes can the system withstand?
  • What effect does a particular type of data combination have on the system?

Using the Black box test method, you can export a set of test cases that meet the following dimensions:

1) The test cases are designed to reduce the number of additional test cases required to achieve reasonable testing;

2) The test cases are designed to tell the existence or absence of certain types of errors, rather than just the errors associated with a particular test.

Black box Test (i)