test(StatsCard): verify massive scaling behavior

components/dashboard/StatsCard.massive-scaling.test.tsx

@@ -0,0 +1,91 @@
+import { render, screen } from '@testing-library/react';
+import { beforeAll, describe, it, expect, vi } from 'vitest';
+import StatsCard from './StatsCard';
+
+beforeAll(() => {
+  class MockIntersectionObserver {
+    observe = vi.fn();
+    unobserve = vi.fn();
+    disconnect = vi.fn();
+  }
+
+  Object.defineProperty(globalThis, 'IntersectionObserver', {
+    writable: true,
+    configurable: true,
+    value: MockIntersectionObserver,
+  });
+});
+
+describe('StatsCard massive scaling', () => {
+  it('renders very large metric values without crashing', () => {
+    render(
+      <StatsCard
+        title="Total Contributions"
+        value="999999999"
+        description="Massive contribution count"
+        icon="Flame"
+      />
+    );
+
+    expect(screen.getByText('Total Contributions')).toBeInTheDocument();
+    expect(screen.getByText(/999,999,999|999999999/)).toBeInTheDocument();
+  });
+
+  it('handles extremely long title text with wrapping', () => {
+    const longTitle =
+      'Very Long Contributor Activity Metric Title That Should Wrap Correctly Without Breaking Layout';
+
+    render(
+      <StatsCard
+        title={longTitle}
+        value="120000"
+        description="Testing long text wrapping"
+        icon="Flame"
+      />
+    );
+
+    expect(screen.getByText(longTitle)).toBeInTheDocument();
+  });
+
+  it('handles extremely long description text safely', () => {
+    const longDescription = 'Activity '.repeat(1000);
+
+    render(
+      <StatsCard title="Activity Logs" value="50000" description={longDescription} icon="Flame" />
+    );
+
+    expect(screen.getByText('Activity Logs')).toBeInTheDocument();
+  });
+
+  it('renders zero and boundary values correctly', () => {
+    render(
+      <StatsCard
+        title="Empty Contributors"
+        value="0"
+        description="No contributor actions"
+        icon="Flame"
+      />
+    );
+
+    expect(screen.getByText('Empty Contributors')).toBeInTheDocument();
+    expect(screen.getByText(/0/)).toBeInTheDocument();
+  });
+
+  it('renders within acceptable performance limits', () => {
+    const start = performance.now();
+
+    render(
+      <StatsCard
+        title="Massive Dataset"
+        value="1000000000"
+        description={'Contributor activity '.repeat(500)}
+        icon="Flame"
+      />
+    );
+
+    const end = performance.now();
+
+    expect(end - start).toBeLessThan(100);
+    expect(screen.getByText('Massive Dataset')).toBeInTheDocument();
+  });
+});