Black box test case design-improvement of boundary value division ideas

table of Contents

Foreword:

Use case description:

to sum up:

---

Foreword:

In software testing, when designing use cases, black box test case design is a very common software testing idea.

The boundary value division idea is also a very common method for black box test case design.

The following are my thoughts on the boundary value division in work.

Use case description:

主流边界值划分思想为5个点就够了例如：[0,100]  -1,0,50,100,101

工作中发现5点划分存在不足，见如下代码：

# case1：[0,100]  -1,0,50,100,101 ==》合适
x = 3
if 0 <= x <= 100:
    print('True')
else:
    print('False')

# case2：[0,100]  -1,0,50,100,101 ==》合适
x = 300
if 0 <= x <= 100:
    print('True')
elif x < 0 or x > 100:
    print('False')

# case3：[0,100]  -1,0,50,100,101 ==》危险
if 0 <= x <= 100:
    print('True')
elif x <= -1 or x >= 101:
    print('False')

# case3：[0,100]  -1,0,50,100,101 ==》不适用
# 若错误把x <= -1 or x >= 101写成了 x == -1 or x == 101、x == -1 or x >= 101、x =< -1 or x == 101
# 这个时候用-1,0,50,100,101来测试依然是发现不出问题的
if 0 <= x <= 100:
    print('True')
elif x == -1 or x == 101:
    print('False')

# case4：[0,100]  -1,0,50,100,101 ==》不适用
# 若错误把x <= -1 or x >= 101写成了 x == -1 or x == 101、x == -1 or x >= 101、x =< -1 or x == 101
# 这个时候用-1,0,50,100,101来测试依然是发现不出问题的
if x == -1 or x == 101:
    print('False')
elif :
    print('True')

to sum up:

Therefore, I personally feel that the most secure is to take a 7-point test: -5, -1,0,50,100,101,105;

When writing code with if, there must be a corresponding else behind, which can increase the robustness of the code (when working at Sangfu, this is very important to the code specification and code review)