I just realized that i don't care much of validation of a filed, for example, if i know it's a number field like amount, i just put the type as number, in fact, user can put text in it.
another question , when i write a code to do something, i don't really think all the possible scenarios that could make it fail. i just make sure it works if user do this or that.
I know i was not doing enough. so can anyone share what they do for validation and testing?
Or just point me to some direction. Appreciated.