Shift-Left

Định nghĩa

Test earlier in SDLC — từ "test sau khi dev done" → test as we go.

Traditional waterfall

Requirements → Design → Code → Test → Deploy
                                ↑
                            Bugs found here = expensive

Shift-left

Requirements → Design → Code → Test → Deploy
     ↑          ↑        ↑       ↑
   Review     Review    Test    Test
   spec       design   while   final
              quality  coding

Practices shift-left

• 3 Amigos — PM + Dev + QA review story together.
• BDD / Gherkin — acceptance criteria as test.
• Story refinement — QA tham gia define "done".
• Static analysis — lint, type-check, security scan in pre-commit.
• Unit test by dev — QA help design test cases.
• Test in PR — automated tests in CI gate merge.

Cost of bug curve

Anti-pattern

• "Shift left = no QA" — QA disappear, dev burned out.
• "Shift left = automation only" — exploratory miss.

Right approach

QA shift-left = involve earlier, NOT disappear. Senior QA hold story refinement, share testing technique to dev.