How to prove the software works?

What do software engineers encounter after another stressfull release? Well, the first thing that we encounter in our group are the bugs that we have released out in the open.  The biggest problem that we as software engineers encounter after a stressfull release is spaghetti-code, also called the big ball of mud. 

The time and money to chase perfection are seldom available, nor should they be. To survive, we must do what it takes to get our software working and out the door on time. Indeed, if a team completes a project with time to spare, today’s managers are likely to take that as a sign to provide less time and money or fewer people the next time around.

You need to deliver quality software on time, and under budget.

Cost: Architecture is a long-term investment. It is easy for the people who are paying the bills to dismiss it, unless there is some tangible immediate benefit, such a tax write-off, or unless surplus money and time happens to be available. Such is seldom the case. More often, the customer needs something working by tomorrow. Often, the people who control and manage the development process simply do not regard architecture as a pressing concern. If programmers know that workmanship is invisible, and managers don’t want to pay for it anyway, a vicious circle is born.

But if this was really the case than each longterm software project would eventually always lead to a big ball of mud.

We know that does not, always, happen. How come? Because the statement that managers do not regard architecture as a pressing concern is false. At least nowadays. Managers in the IT field very well know that maintainability is key to the business.

[..] business becomes dependent upon the data driving it. Businesses have become critically dependent on their software and computing infrastructures. There are numerous mission critical systems that must be on-the-air twenty-four hours a day/seven days per week. If these systems go down, inventories can not be checked, employees can not be paid, aircraft cannot be routed, and so on. [..]

Therefore it is at the heart of the business to seek ways to keep systems far away from the big ball of mud. That the system is still maintainable. That the system actually works and that we, as coders, can prove it does. Does your manager and or stakeholder ask you if you have finished your coding today, does she ask you if the release that has fixes A, B and C can be done today or does she ask if the software that will be released actually works? And have you proved it works? With what?

What ways do we have to prove our stakeholders our software works? Are those green lights of our software-unit tests enough? If yes, won’t that only prove our big-ball of mud is still doing what we expect it to do? How can you prove your design is right?

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