diff --git a/apps/web/src/components/timeline/timelineProjectRows.test.ts b/apps/web/src/components/timeline/timelineProjectRows.test.ts
new file mode 100644
index 0000000..e4fc72b
--- /dev/null
+++ b/apps/web/src/components/timeline/timelineProjectRows.test.ts
@@ -0,0 +1,110 @@
+import { describe, expect, it } from "vitest";
+import { PROJECT_HEADER_HEIGHT, ROW_HEIGHT, SUB_LANE_HEIGHT } from "./timelineConstants.js";
+import { estimateProjectRowHeight, buildProjectFlatRows } from "./timelineProjectRows.js";
+
+describe("timelineProjectRows", () => {
+  it("falls back to the default row height when no row is provided", () => {
+    expect(estimateProjectRowHeight(undefined)).toBe(ROW_HEIGHT);
+  });
+
+  it("returns header and open-demand row heights from the row type", () => {
+    expect(
+      estimateProjectRowHeight({
+        type: "header",
+        key: "header-project_1",
+        project: {} as never,
+      }),
+    ).toBe(PROJECT_HEADER_HEIGHT);
+
+    expect(
+      estimateProjectRowHeight({
+        type: "open-demand",
+        key: "open-demand-project_1",
+        projectId: "project_1",
+        openDemandCount: 2,
+        layout: {
+          visibleOpenDemands: [],
+          laneMap: new Map(),
+          laneCount: 2,
+          rowHeight: SUB_LANE_HEIGHT * 2 + 16,
+        },
+      }),
+    ).toBe(SUB_LANE_HEIGHT * 2 + 16);
+  });
+
+  it("skips open-demand rows when a project has no open demands", () => {
+    const rows = buildProjectFlatRows(
+      [
+        {
+          id: "project_1",
+          resourceRows: [
+            {
+              resource: { id: "resource_1" },
+              allocs: [{ id: "alloc_1" }],
+            },
+          ],
+        },
+      ] as never,
+      new Map(),
+      new Map(),
+    );
+
+    expect(rows.map((row) => row.type)).toEqual(["header", "resource"]);
+    expect(rows[1]).toMatchObject({
+      key: "project_1-resource_1",
+      metricsKey: "project_1:resource_1",
+    });
+  });
+
+  it("uses optimistic open-demand overrides when computing lane layout", () => {
+    const rows = buildProjectFlatRows(
+      [
+        {
+          id: "project_1",
+          resourceRows: [],
+        },
+      ] as never,
+      new Map([
+        [
+          "project_1",
+          [
+            {
+              id: "demand_1",
+              startDate: "2026-04-10",
+              endDate: "2026-04-10",
+            },
+            {
+              id: "demand_2",
+              startDate: "2026-04-11",
+              endDate: "2026-04-11",
+            },
+          ],
+        ],
+      ]) as never,
+      new Map([
+        [
+          "demand_2",
+          {
+            startDate: new Date("2026-04-10T00:00:00.000Z"),
+            endDate: new Date("2026-04-12T00:00:00.000Z"),
+          },
+        ],
+      ]),
+    );
+
+    const openDemandRow = rows.find((row) => row.type === "open-demand");
+    expect(openDemandRow?.type).toBe("open-demand");
+
+    if (openDemandRow?.type !== "open-demand") {
+      throw new Error("expected open-demand row");
+    }
+
+    expect(openDemandRow.layout.visibleOpenDemands[1]?.startDate).toEqual(
+      new Date("2026-04-10T00:00:00.000Z"),
+    );
+    expect(openDemandRow.layout.laneCount).toBe(2);
+    expect(openDemandRow.layout.laneMap.get("demand_1")).toBe(0);
+    expect(openDemandRow.layout.laneMap.get("demand_2")).toBe(1);
+    expect(openDemandRow.layout.rowHeight).toBe(SUB_LANE_HEIGHT * 2 + 16);
+  });
+});