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Generally speaking, there are bugs in software because of unclear requirements, software complexity, programming errors, changes in requirements, errors made in bug tracking, time pressure, poorly documented code and/or bugs in tools used in software development.
� There are unclear software requirements because there is miscommunication as to what the software should or shouldn't do.
� Software complexity. All of the followings contribute to the exponential growth in software and system complexity: Windows interfaces, client-server and distributed applications, data communications, enormous relational databases and the sheer size of applications.
� Programming errors occur because programmers and software engineers, like everyone else, can make mistakes.
� As to changing requirements, in some fast-changing business environments, continuously modified requirements are a fact of life. Sometimes customers do not understand the effects of changes, or understand them but request them anyway. And the changes require redesign of the software, rescheduling of resources and some of the work already completed have to be redone or discarded and hardware requirements can be effected, too.
� Bug tracking can result in errors because the complexity of keeping track of changes can result in errors, too.
� Time pressures can cause problems, because scheduling of software projects is not easy and it often requires a lot of guesswork and when deadlines loom and the crunch comes, mistakes will be made.
� Code documentation is tough to maintain and it is also tough to modify code that is poorly documented. The result is bugs. Sometimes there is no incentive for programmers and software engineers to document their code and write clearly documented, understandable code. Sometimes developers get kudos for quickly turning out code, or programmers and software engineers feel they cannot have job security if everyone can understand the code they write, or they believe if the code was hard to write, it should be hard to read.
� Software development tools , including visual tools, class libraries, compilers, scripting tools, can introduce their own bugs. Other times the tools are poorly documented, which can create additional bugs. Q: Give me five common problems that occur during software development!
A: Poorly written requirements, unrealistic schedules, inadequate testing, adding new features after development is underway and poor communication.
1. Requirements are poorly written when requirements are unclear, incomplete, too general, or not testable; therefore there will be problems.
2. The schedule is unrealistic if too much work is crammed in too little time.
3. Software testing is inadequate if none knows whether or not the software is any good until customers complain or the system crashes.
4. It's extremely common that new features are added after development is underway.
5. Miscommunication either means the developers don't know what is needed, or customers have unrealistic expectations and therefore problems are guaranteed. Q: Give me five solutions to problems that occur during software development!
A: Solid requirements, realistic schedules, adequate testing, firm requirements and good communication.
1. Ensure the requirements are solid, clear, complete, detailed, cohesive, attainable and testable. All players should agree to requirements. Use prototypes to help nail down requirements.
2. Have schedules that are realistic. Allow adequate time for planning, design, testing, bug fixing, re-testing, changes and documentation. Personnel should be able to complete the project without burning out.
3. Do testing that is adequate. Start testing early on, re-test after fixes or changes, and plan for sufficient time for both testing and bug fixing.
4. Avoid new features. Stick to initial requirements as much as possible. Be prepared to defend design against changes and additions, once development has begun and be prepared to explain consequences. If changes are necessary, ensure they're adequately reflected in related schedule changes. Use prototypes early on so customers' expectations are clarified and customers can see what to expect; this will minimize changes later on.
5. Communicate. Require walkthroughs and inspections when appropriate; make extensive use of e-mail, networked bug-tracking tools, tools of change management. Ensure documentation is available and up-to-date. Use documentation that is electronic, not paper. Promote teamwork and cooperation.
Q: Do automated testing tools make testing easier?
A: Yes and no. For larger projects, or ongoing long-term projects, they can be valuable. But for small projects, the time needed to learn and implement them is usually not worthwhile. A common type of automated tool is the record/playback type. For example, a test engineer clicks through all combinations of menu choices, dialog box choices, buttons, etc. in a GUI and has an automated testing tool record and log the results. The recording is typically in the form of text, based on a scripting language that the testing tool can interpret. If a change is made (e.g. new buttons are added, or some underlying code in the application is changed), the application is then re-tested by just playing back the recorded actions and compared to the logged results in order to check effects of the change. One problem with such tools is that if there are continual changes to the product being tested, the recordings have to be changed so often that it becomes a very time-consuming task to continuously update the scripts. Another problem with such tools is the interpretation of the results (screens, data, logs, etc.) that can be a time-consuming task. |
