test(web): cover timeline live preview render edges

apps/web/src/hooks/timelineLivePreview.test.ts

@@ -39,6 +39,17 @@ function createSession(element: HTMLElement): LivePreviewSession {
   };
 }
 
+function renderScheduledPreview(session: LivePreviewSession) {
+  let frameCallback: FrameRequestCallback | null = null;
+  vi.stubGlobal("requestAnimationFrame", vi.fn((callback: FrameRequestCallback) => {
+    frameCallback = callback;
+    return 1;
+  }));
+
+  scheduleLivePreview(session);
+  frameCallback?.(0);
+}
+
 describe("timelineLivePreview", () => {
   beforeEach(() => {
     vi.unstubAllGlobals();
@@ -132,6 +143,57 @@ describe("timelineLivePreview", () => {
     expect(datesMatch(null, null)).toBe(false);
   });
 
+  it("renders move previews with snapped left offsets and residual transforms", () => {
+    const element = createElement();
+    const session = createSession(element);
+
+    session.pointerDeltaX = 50;
+    session.daysDelta = 1;
+
+    renderScheduledPreview(session);
+
+    expect(session.frame).toBeNull();
+    expect(element.style.left).toBe("44px");
+    expect(element.style.width).toBe("48px");
+    expect(element.style.transform).toBe("scale(1) translateX(18px)");
+  });
+
+  it("clamps resize-start previews to the minimum cell width", () => {
+    const element = createElement();
+    const session = createSession(element);
+
+    session.mode = "resize-start";
+    session.cellWidth = 20;
+    session.targets[0]!.baseLeft = 10;
+    session.targets[0]!.baseWidth = 60;
+    session.pointerDeltaX = 80;
+    session.daysDelta = 1;
+
+    renderScheduledPreview(session);
+
+    expect(element.style.left).toBe("50px");
+    expect(element.style.width).toBe("20px");
+    expect(element.style.transform).toBe("scale(1)");
+  });
+
+  it("clamps resize-end previews to the minimum cell width", () => {
+    const element = createElement();
+    const session = createSession(element);
+
+    session.mode = "resize-end";
+    session.cellWidth = 20;
+    session.targets[0]!.baseLeft = 10;
+    session.targets[0]!.baseWidth = 30;
+    session.pointerDeltaX = -40;
+    session.daysDelta = 0;
+
+    renderScheduledPreview(session);
+
+    expect(element.style.left).toBe("10px");
+    expect(element.style.width).toBe("20px");
+    expect(element.style.transform).toBe("scale(1)");
+  });
+
   it("schedules at most one animation frame for a preview session", () => {
     const element = createElement();
     const session = createSession(element);