test(web): cover allocation visual state helpers

apps/web/src/components/timeline/allocationVisualState.test.ts

@@ -0,0 +1,100 @@
+import { describe, expect, it } from "vitest";
+import {
+  applyPointerOffsetPreviewRect,
+  applyVisualOverrides,
+  getDragPointerOffset,
+} from "./allocationVisualState.js";
+
+describe("allocationVisualState", () => {
+  it("keeps only the residual pointer offset after full-day snapping", () => {
+    expect(getDragPointerOffset(53, 2, 20)).toBe(13);
+    expect(getDragPointerOffset(-53, -2, 20)).toBe(-13);
+  });
+
+  it("clamps resize-start preview rectangles to the configured minimum width", () => {
+    expect(
+      applyPointerOffsetPreviewRect({
+        left: 100,
+        width: 40,
+        mode: "resize-start",
+        pointerOffsetX: 35,
+        minWidth: 20,
+      }),
+    ).toEqual({
+      left: 120,
+      width: 20,
+    });
+  });
+
+  it("keeps move previews stable when there is no residual pointer offset", () => {
+    expect(
+      applyPointerOffsetPreviewRect({
+        left: 100,
+        width: 40,
+        mode: "move",
+        pointerOffsetX: 0,
+        minWidth: 20,
+      }),
+    ).toEqual({
+      left: 100,
+      width: 40,
+    });
+  });
+
+  it("returns the original entries array when no override matches", () => {
+    const entries = [
+      {
+        id: "alloc_1",
+        startDate: "2026-04-10",
+        endDate: "2026-04-12",
+        label: "original",
+      },
+    ] as const;
+
+    const result = applyVisualOverrides(
+      entries,
+      new Map([
+        [
+          "alloc_other",
+          {
+            startDate: new Date("2026-04-20T00:00:00.000Z"),
+            endDate: new Date("2026-04-21T00:00:00.000Z"),
+          },
+        ],
+      ]),
+    );
+
+    expect(result).toBe(entries);
+  });
+
+  it("clones override dates without mutating unaffected entries", () => {
+    const entries = [
+      {
+        id: "alloc_1",
+        startDate: "2026-04-10",
+        endDate: "2026-04-12",
+        label: "changed",
+      },
+      {
+        id: "alloc_2",
+        startDate: "2026-04-15",
+        endDate: "2026-04-16",
+        label: "unchanged",
+      },
+    ];
+    const override = {
+      startDate: new Date("2026-04-20T00:00:00.000Z"),
+      endDate: new Date("2026-04-22T00:00:00.000Z"),
+    };
+
+    const result = applyVisualOverrides(entries, new Map([["alloc_1", override]]));
+
+    expect(result).not.toBe(entries);
+    expect(result[0]).not.toBe(entries[0]);
+    expect(result[1]).toBe(entries[1]);
+    expect(result[0]?.startDate).toEqual(new Date("2026-04-20T00:00:00.000Z"));
+    expect(result[0]?.endDate).toEqual(new Date("2026-04-22T00:00:00.000Z"));
+    expect(result[0]?.startDate).not.toBe(override.startDate);
+    expect(result[0]?.endDate).not.toBe(override.endDate);
+  });
+});