The main thing all these guys do is to ship the most trivial thing that will work (is better than competitors) but leave it open for improvements. Tests are wr

The main thing all these guys do is to ship the most trivial thing that will work (is better than competitors) but leave it open for improvements. Tests are written sometimes second, not first. Specifically regression only testing is pretty good and less intensive than full testing everything. But to know about regressions and problems you need reports and to do that, the software has to be shipped, in use and the report channels have to work well.