I read somewhere that Alpha testing generally carried out according to developer's point of view unlike Beta testing which is carried out according to users point of view.
According to above definition, Alpha testing should carried out during/
after development phase.
Hope this ansewr will help you .
Please correct me if I am wrong somewhere.
Any software primarily goes through two phases of testing :
Alpha Testing : This is the first phase of testing usually within the development enviroment. As per my experince it always a good idea to begin this phase during requirements stage of the software, by being a observer at the requirements meetings and then developing related testcases based on the requirements.
Beta Testing : This is the second phase of testing when the software is almost ready to be delivered and is handed out to external users for testing and to get their feed back