test: add FollowButton unit tests

src/components/__tests__/FollowButton.test.tsx

@@ -0,0 +1 @@
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';import { describe, it, expect, vi } from 'vitest';import FollowButton from '../common/FollowButton';describe('FollowButton', () => {  it('renders Follow when not following', () => {    render(<FollowButton creatorAddress="0x123" isFollowing={false} onFollow={vi.fn()} onUnfollow={vi.fn()} />);    expect(screen.getByTestId('follow-button')).toHaveTextContent('Follow');  });  it('renders Following when following', () => {    render(<FollowButton creatorAddress="0x123" isFollowing={true} onFollow={vi.fn()} onUnfollow={vi.fn()} />);    expect(screen.getByTestId('follow-button')).toHaveTextContent('Following');  });  it('calls onFollow with correct address when not following', async () => {    const onFollow = vi.fn().mockResolvedValue(undefined);    render(<FollowButton creatorAddress="0x123" isFollowing={false} onFollow={onFollow} onUnfollow={vi.fn()} />);    fireEvent.click(screen.getByTestId('follow-button'));    await waitFor(() => expect(onFollow).toHaveBeenCalledWith('0x123'));  });  it('calls onUnfollow when already following', async () => {    const onUnfollow = vi.fn().mockResolvedValue(undefined);    render(<FollowButton creatorAddress="0x123" isFollowing={true} onFollow={vi.fn()} onUnfollow={onUnfollow} />);    fireEvent.click(screen.getByTestId('follow-button'));    await waitFor(() => expect(onUnfollow).toHaveBeenCalled());  });  it('disables button and shows loading while pending', async () => {    const onFollow = vi.fn().mockImplementation(() => new Promise(resolve => setTimeout(resolve, 100)));    render(<FollowButton creatorAddress="0x123" isFollowing={false} onFollow={onFollow} onUnfollow={vi.fn()} />);    fireEvent.click(screen.getByTestId('follow-button'));    expect(screen.getByTestId('follow-button')).toBeDisabled();    expect(screen.getByTestId('follow-button')).toHaveTextContent('Loading...');    await waitFor(() => expect(onFollow).toHaveBeenCalled());  });});

src/components/common/FollowButton.tsx

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+import { useState } from 'react';
+import { Button } from '@/components/ui/button';
+
+interface FollowButtonProps {
+  creatorAddress: string;
+  isFollowing: boolean;
+  onFollow: (creatorAddress: string) => Promise<void>;
+  onUnfollow: (creatorAddress: string) => Promise<void>;
+}
+
+export default function FollowButton({
+  creatorAddress,
+  isFollowing,
+  onFollow,
+  onUnfollow,
+}: FollowButtonProps) {
+  const [loading, setLoading] = useState(false);
+
+  const handleClick = async () => {
+    setLoading(true);
+    try {
+      if (isFollowing) {
+        await onUnfollow(creatorAddress);
+      } else {
+        await onFollow(creatorAddress);
+      }
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  return (
+    <Button
+      onClick={handleClick}
+      disabled={loading}
+      variant={isFollowing ? 'outline' : 'default'}
+      data-testid="follow-button"
+    >
+      {loading ? 'Loading...' : isFollowing ? 'Following' : 'Follow'}
+    </Button>
+  );
+}