How software is full tested and has high quality, before moving to production?

Quality Assurance begins during Specification
Review.

The QA team should have the opportunity to
review each specification and to find
issues and make suggestions.

The QA team should look for unclear
requirements, requirements that are
not defined well enough to create test
cases around, and for requirements
that might affect other areas of the
software.

Time spent in requirements review
and correction can pay big dividends.