# Talking about the software white box test and black box test, we must first distinguish between the following two concepts, "defects" and "bug".
"Defect" can cause multiple bugs, which may be caused by programming, database design, etc.
"BUG" is a manifestation of a defect, which is different from defects.
# Black box test can only observe the external performance of the software, even if the software input and output is correct, it does not explain that the software is correct. Because the program is likely to have the correct result with the wrong operation, such as "negative negative, wrong", only white box tests can find real reasons.
# Box test work must be early, do not wait until the entire system is developed, because the defect will get more and more distributed, it is deeper, but the price of the test is greatly increased. The worst is unable to estimate the workload of testing and implicit error, so that progress is lost. Therefore, it is the practice of "not paying" for the province's presupposition or the provision of unit testing or "scalpered".
