diff --git a/src/app/(app)/collection-pool/view-model.test.ts b/src/app/(app)/collection-pool/view-model.test.ts
index 71ad283..0e816f2 100644
--- a/src/app/(app)/collection-pool/view-model.test.ts
+++ b/src/app/(app)/collection-pool/view-model.test.ts
@@ -195,3 +195,74 @@ describe("buildProximityMarkerMap", () => {
     expect(markers.get("sup-a")).not.toBe(markers.get("sup-c"));
   });
 });
+
+describe("buildVisibleRows sort modes (nearby pinning)", () => {
+  const todayYmd = "2026-07-09";
+
+  it("operational sort is stable on the same input regardless of readyFilter", () => {
+    const rows: CollectionPoolViewRow[] = [
+      makeRow({ id: "a", poNumber: "PO-A", updated: "2026-07-02T00:00:00.000Z" }),
+      makeRow({ id: "b", poNumber: "PO-B", updated: "2026-07-01T00:00:00.000Z" }),
+    ];
+
+    const all = buildVisibleRows(rows, {
+      todayYmd,
+      searchText: "",
+      readyFilter: "all",
+      sortMode: "operational",
+    });
+    const ready = buildVisibleRows(rows, {
+      todayYmd,
+      searchText: "",
+      readyFilter: "ready",
+      sortMode: "operational",
+    });
+    const pending = buildVisibleRows(rows, {
+      todayYmd,
+      searchText: "",
+      readyFilter: "unready",
+      sortMode: "operational",
+    });
+
+    expect(all.map((r) => r.id)).toEqual(["a", "b"]);
+    expect(ready.map((r) => r.id)).toEqual(["a", "b"]);
+    expect(pending.map((r) => r.id)).toEqual(["a", "b"]);
+  });
+
+  it("nearby sort groups rows by clusterSortKey ascending", () => {
+    const rows: CollectionPoolViewRow[] = [
+      makeRow({ id: "c", clusterSortKey: "cluster-c" }),
+      makeRow({ id: "a", clusterSortKey: "cluster-a" }),
+      makeRow({ id: "b", clusterSortKey: "cluster-b" }),
+    ];
+
+    const out = buildVisibleRows(rows, {
+      todayYmd,
+      searchText: "",
+      readyFilter: "all",
+      sortMode: "nearby",
+    });
+
+    expect(out.map((r) => r.id)).toEqual(["a", "b", "c"]);
+  });
+
+  it("nearby sort sinks rows with missing clusterSortKey to the end", () => {
+    const rows: CollectionPoolViewRow[] = [
+      makeRow({ id: "no-coords-1", clusterSortKey: undefined }),
+      makeRow({ id: "a", clusterSortKey: "cluster-a" }),
+      makeRow({ id: "no-coords-2", clusterSortKey: undefined }),
+      makeRow({ id: "b", clusterSortKey: "cluster-b" }),
+    ];
+
+    const out = buildVisibleRows(rows, {
+      todayYmd,
+      searchText: "",
+      readyFilter: "all",
+      sortMode: "nearby",
+    });
+
+    // Rows WITH coords come first, ordered by cluster key.
+    // Rows WITHOUT coords come last (sink to the end).
+    expect(out.map((r) => r.id)).toEqual(["a", "b", "no-coords-1", "no-coords-2"]);
+  });
+});