test(widgets): add unit tests for FileExplorer widget

packages/widgets/src/FileExplorer.test.ts

@@ -0,0 +1,135 @@
+// ─────────────────────────────────────────────────────
+// @termuijs/widgets — Tests for FileExplorer
+// ─────────────────────────────────────────────────────
+
+import { describe, it, expect, vi } from 'vitest';
+import { FileExplorer } from './FileExplorer.js';
+import type { FileItem } from './FileExplorer.js';
+
+// ── Helpers ───────────────────────────────────────────
+
+const makeFiles = (): FileItem[] => [
+    { name: 'readme.md',  path: '/root/readme.md',  isDirectory: false },
+    { name: 'src',        path: '/root/src',         isDirectory: true  },
+    { name: 'index.ts',   path: '/root/index.ts',    isDirectory: false },
+];
+
+// ── Tests ─────────────────────────────────────────────
+
+describe('FileExplorer', () => {
+
+    // constructor
+    it('defaults root to "./"', () => {
+        const fe = new FileExplorer();
+        expect(fe.root).toBe('./');
+    });
+
+    it('uses provided root option', () => {
+        const fe = new FileExplorer({ root: '/home/user' });
+        expect(fe.root).toBe('/home/user');
+    });
+
+    // setFiles
+    it('setFiles loads files and resets selectedIndex to 0', () => {
+        const fe = new FileExplorer();
+        const files = makeFiles();
+        fe.setFiles(files);
+        fe.next(); // move to index 1
+        fe.setFiles(files); // reload resets to 0
+        expect(fe.current?.name).toBe('readme.md');
+    });
+
+    // next
+    it('next() moves selection down by one', () => {
+        const fe = new FileExplorer();
+        fe.setFiles(makeFiles());
+        fe.next();
+        expect(fe.current?.name).toBe('src');
+    });
+
+    it('next() does not go past the last item', () => {
+        const fe = new FileExplorer();
+        fe.setFiles(makeFiles());
+        fe.next();
+        fe.next();
+        fe.next(); // already at last — should stay
+        expect(fe.current?.name).toBe('index.ts');
+    });
+
+    // previous
+    it('previous() moves selection up by one', () => {
+        const fe = new FileExplorer();
+        fe.setFiles(makeFiles());
+        fe.next();
+        fe.next(); // at index 2
+        fe.previous();
+        expect(fe.current?.name).toBe('src');
+    });
+
+    it('previous() does not go below 0', () => {
+        const fe = new FileExplorer();
+        fe.setFiles(makeFiles());
+        fe.previous(); // already at 0 — should stay
+        expect(fe.current?.name).toBe('readme.md');
+    });
+
+    // select
+    it('select() adds current file path to selected set', () => {
+        const fe = new FileExplorer();
+        fe.setFiles(makeFiles());
+        fe.select();
+        expect(fe.selected).toContain('/root/readme.md');
+    });
+
+    it('select() calls onSelect callback with correct path', () => {
+        const onSelect = vi.fn();
+        const fe = new FileExplorer({ onSelect });
+        fe.setFiles(makeFiles());
+        fe.next(); // move to src
+        fe.select();
+        expect(onSelect).toHaveBeenCalledWith('/root/src');
+    });
+
+    it('select() is a no-op when file list is empty', () => {
+        const onSelect = vi.fn();
+        const fe = new FileExplorer({ onSelect });
+        fe.setFiles([]);
+        fe.select();
+        expect(onSelect).not.toHaveBeenCalled();
+        expect(fe.selected).toHaveLength(0);
+    });
+
+    // search
+    it('search() filters files by name case-insensitively', () => {
+        const fe = new FileExplorer();
+        fe.setFiles(makeFiles());
+        const results = fe.search('README');
+        expect(results).toHaveLength(1);
+        expect(results[0].name).toBe('readme.md');
+    });
+
+    it('search() returns empty array when no match', () => {
+        const fe = new FileExplorer();
+        fe.setFiles(makeFiles());
+        const results = fe.search('nonexistent');
+        expect(results).toHaveLength(0);
+    });
+
+    // current getter
+    it('current returns undefined when no files loaded', () => {
+        const fe = new FileExplorer();
+        expect(fe.current).toBeUndefined();
+    });
+
+    // selected getter
+    it('selected returns all selected paths', () => {
+        const fe = new FileExplorer();
+        fe.setFiles(makeFiles());
+        fe.select();       // select readme.md
+        fe.next();
+        fe.select();       // select src
+        expect(fe.selected).toHaveLength(2);
+        expect(fe.selected).toContain('/root/readme.md');
+        expect(fe.selected).toContain('/root/src');
+    });
+});