Ideally QA and testers should be involved if not from the day one then from very early stages of a software development project, regardless of the process used (waterfall or agile). The test team will need to:
Ensure that project or sprint requirements are clear, measurable and testable. In an ideal world each requirement will have a fit criterion written down at this stage. Determine what information needs to be automatically logged to troubleshoot any defects.
Prepare a project specific test strategy and determine which QA steps are going to be required and at which project stages: integration, stress, compatibility, penetration, conformance, usability, performance, beta testing etc. Determine acceptable defect thresholds and work out classification system for defect severity, specify guidelines for defect reporting.
Specify, arrange and prepare test environment: test infrastructure and mock services as necessary; obtain, sanitise and prepare test data; write scripts to quickly refresh test environment when necessary; establish processes for defect tracking, communication and resolution; prepare for recruitment or recruit users for beta, usability or acceptance testing.
Supply all the relevant information to form project schedule, work break down structure and resource plan.
Write test scripts.
Bring themselves up to speed with the problem domain, system AS-IS and proposed solution.
Usually this is not a question of whether a test team may provide any useful input into the project on an early stage, nor if such an input is beneficial. It is a question, however, of the extent to which an organisation can afford the aforementioned activities. There is always a trade off between available time, budget and resource versus the level of known quality of the end result.
