Blog
Mert Özen's blog posts on software development, backend, frontend, and DevOps.
The V-Model: Pairing Every Development Step with a Test Level
In the V-Model testing isn't done last, it's designed on the left arm: requirements pair with acceptance tests, system design with system tests, architecture with integration tests, module design with unit tests. We tie Bookstore's 14-day return rule to its requirement with xUnit v3 traits, list the four tests of REQ-RET-01 with one command, and see in real test output which requirement a boundary bug breaks.
The Waterfall Model: What Royce Actually Said in 1970
In his 1970 paper Royce drew the single-pass model but immediately called it risky, because problems such as timing and memory first appear in testing and force a redesign. We cover his five fixes (program design first, document it, do it twice, plan testing, involve the customer), the story of the name "Waterfall" and DOD-STD-2167, and how integration blows up in the last month of Bookstore's returns feature.
What Is the SDLC? A Software System's Life from Idea to Retirement
The SDLC (Software Development Life Cycle) is the full set of phases software goes through from idea to retirement: requirements, design, implementation, test, deployment, operations and retirement; models don't change the phases, only their order and repetition. Using Bookstore's returns feature we look at each phase's output, the weight of maintenance, the four process groups of ISO/IEC/IEEE 12207:2026 and the forgotten retirement phase.