How to Reduce Schedule Risk with Technical Practices: Story Wall Evolution, Unit Testing, and Trunk Development

In the previous article we discussed product‑front demand management, but planning alone does not guarantee on‑time delivery. This article shares three technical improvements the Audio UI team applied to avoid schedule risk.

Story Wall Evolution

We transformed a traditional ToDo/Doing/Done board into a value‑stream‑focused wall where each column represents a workflow activity (Design, Development, Test, Done). Small story cards flow from left to right, making bottlenecks and "bad smells" visible, such as oversized stories and work‑only activity breakdowns.

We added columns for "Code Review" and "Development Self‑Test" to keep work‑in‑progress visible and to enforce that code is reviewed before moving forward.

Definition of Done (DoD)

For each stage we defined concrete quality criteria: design documents must be reviewed before coding; code must pass unit tests and a code review; all test cases must succeed and bugs be fixed before a story is marked Done.

On‑board Design

Instead of writing design documents in Word first, the designer sketches the design on a whiteboard with the whole team (max 5 minutes), gathers feedback, then quickly produces a concise document. This reduces time spent on polishing unused designs.

Prioritising Code Review Over Coding

We introduced a dedicated "code review" column so that developers know which stories are awaiting review, preventing the pile‑up of work in the Development column.

Development Self‑Test

Developers run their own unit tests and fix obvious bugs before handing the story to testers, reducing rework and improving delivery confidence.

Limiting Work‑In‑Progress (WIP)

We apply Lean WIP limits: the tester evaluates daily capacity; if the test queue exceeds capacity, the Tech Lead stops new development and helps the tester finish pending stories.

Unit Testing & Test‑Shift‑Left

We introduced CppUnit unit tests, achieving a 1:1.2 ratio of production to test code. Benefits included higher confidence in commits, faster bug fixes, and quicker feature validation in subsequent projects.

Trunk‑Based Development Motivation

Previously the team used a three‑level branch strategy (personal, team, product). Frequent large merges caused pain, so we eliminated team branches and committed directly to the main trunk, supported by automated builds, code‑review scores, content checks, and manual testing.

Overall, these lean and quality‑centric practices—Value Stream Mapping, breaking work into small units, continuous improvement, WIP limits, and built‑in quality—helped the team keep demand flow smooth, reduce waste, and deliver with fewer bugs.