Phase 3 UI Migration Milestones

Phase 3 UI Migration Milestones (Streamlit → React + FastAPI)

This document is the execution checklist for migrating the Testo UI from the Streamlit prototype (testo_ui/streamlit_app.py) to a decoupled React SPA (frontend/) backed by FastAPI (testo_api/), while keeping testo_core as the single source of truth for orchestration and preserving CI/NDJSON contracts.

References:

• docs/Architecture/Deep Dive - Execution Logic.md
• docs/CLI Commands/Troubleshooting and Error Codes.md
• docs/Processes & Guides/Streamlit to React Migration Guide.md

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Phase 0 — Contracts locked (no UI changes)

• Execution model: standardize on plan/cycle execution (testo run lifecycle) as the primary web contract.
• Streaming transport: standardize on SSE from backend → frontend.
• Event schema: SSE data: payloads are the same objects as NDJSON events.ndjson lines (top-level event field and documented payload shapes).

Exit criteria:

• A single written contract for: plan_started, stage_started, stage_finished, plan_finished, plan_aborted, cycle_trigger, error.

Rollback:

• Keep Streamlit runnable.

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Phase 1 — Backend: plan/cycle execution API (headless)

Deliverables:

• POST /api/v1/cycles/{cycle}/executions to start a cycle run.
• GET /api/v1/cycle-executions/{id} for execution status.
• GET /api/v1/cycle-executions/{id}/events SSE stream that tails artifacts/<cycle>/events.ndjson.

Exit criteria:

• A cycle run can be started and observed end-to-end via SSE.
• Durable artifacts are written under artifacts/<cycle>/ (events.ndjson, plan_result.json).

Rollback:

• Continue using the existing headless execution endpoints (/api/v1/executions) for legacy UI paths.

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Phase 2 — Frontend: React scaffold + contract mapping

Deliverables:

• Vite + TypeScript app under frontend/.
• Routes/pages:
  • DashboardHome: uses /api/v1/dashboard/overview
  • Runner/LiveExecutionConsole: uses new cycle execution endpoints + SSE
  • History/ReportViewer: uses /api/v1/runs / /api/v1/runs/{id} / /api/v1/runs/{id}/reports

Exit criteria:

• The SPA loads, navigates, and can start a cycle run with live event streaming.

Rollback:

• Streamlit remains available for the same user journeys.

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Phase 3 — Runner UX hardening (logs + artifacts + reports)

Deliverables:

• Runner view shows:
  • stage timeline and final exit classification
  • direct links to run.log (per stage) and events.ndjson / plan_result.json
• History links open the right report surfaces:
  • Allure Server per run_id when configured
  • static report mirrors (Allure/Extent) where available

Exit criteria:

• Feature parity with Streamlit “Execution + Analytics + History” journeys.

Rollback:

• Streamlit stays as fallback while production traffic is gradually shifted.

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Phase 4 — Production readiness (multi-user + isolation)

Deliverables:

• Concurrency control per cycle and/or per execution workspace.
• Optional cancellation endpoint(s) and cleanup.
• AuthN/AuthZ if required.
• Better SSE resilience: reconnection with offset semantics (server can support Last-Event-ID or explicit offset).

Exit criteria:

• Stable operations under concurrent users, with predictable resource usage and clean teardown.

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[!note] Superseded in part (2026-07-04) The Phase 3 route map (/runner, /history, /execution) was reorganized by the Phase 5 UI redesign: cycles-first navigation, cycle discovery endpoints, and a consolidated Run panel. Old routes redirect. See Phase 5 UI Redesign - Cycles-First Navigation.

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