[Molecule-Platform-Evolvement-Manager]
Closes the second item from #2071 (Canvas test gaps follow-up):
adds behavioural coverage for the custom React Flow edge that renders
delegation counts between workspaces and routes a click into the
source workspace's Activity feed.
10 cases across 2 buckets:
**Render (6):**
- Empty label → BaseEdge only, NO portaled HTML pill (the most
common state for cold edges; pill must not render-through-empty)
- Non-empty label → pill renders with the exact label text
- isHot=true → violet accent classes; blue accent NOT present
- isHot=false → blue accent classes
- ARIA pluralization: count=1 → "1 delegation from …" (singular)
- ARIA pluralization: count=7 → "7 delegations from …" (plural)
**Click behaviour (4):**
- Click → selectNode(source)
- FRESH selection (selectedNodeId != source) → also setPanelTab("activity")
- RE-click of already-selected source → setPanelTab MUST NOT fire
(this is the regression-locked guarantee — preserves the user's
current tab when they intentionally moved to Chat / Memory while
inspecting the same peer)
- stopPropagation: parent onClick must NOT see the event (otherwise
the canvas Pane's clear-selection handler would fire and undo the
edge's own selectNode call)
## Mocking strategy
- `@xyflow/react`: BaseEdge → <g data-testid>, EdgeLabelRenderer →
inline pass-through (no portal), getBezierPath → fixed [path, x, y].
Lets the test render the component without a ReactFlow provider.
- `@/store/canvas`: vi.hoisted-shared mock state with selectNode +
setPanelTab spies and a mutable selectedNodeId. The store's
getState() returns the same object so the click handler's
`useCanvasStore.getState().selectedNodeId` lookup works.
Pattern matches the existing `A2ATopologyOverlay.test.tsx` setup
in the same module.
## Test plan
- [x] All 10 cases pass locally (`vitest run A2AEdge.test.tsx` — ~1.3s)
- [x] No changes to the SUT — pure additive coverage
- [ ] CI green
## Remaining #2071 items
- OrgCancelButton tests
- useDragHandlers tests
Each is a separate PR.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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