Add todoUtils tests

tests/todoUtils.test.ts

@@ -0,0 +1,45 @@
+import { describe, it, expect } from 'vitest';
+import { limitTodos, todoKey } from '../src/core/todoUtils';
+import { TodoItem } from '../src/parser/types';
+
+
+describe('limitTodos', () => {
+  it('filters out invalid todos and limits the result', () => {
+    const todos: TodoItem[] = [
+      { tag: 'TODO', text: 'short', file: 'a.ts', line: 1 },
+      { tag: 'FIXME', text: 'Fix the login', file: 'b.ts', line: 2 },
+      { tag: 'TODO', text: 'Refactor component', file: 'c.ts', line: 3 },
+      { tag: 'BUG', text: 'Another fix', file: 'd.ts', line: 4 },
+    ];
+
+    const limited = limitTodos(todos, 2);
+
+    expect(limited.length).toBe(2);
+    expect(limited[0].text).toBe('Fix the login');
+    expect(limited[1].text).toBe('Refactor component');
+  });
+});
+
+describe('todoKey', () => {
+  it('can be used to remove duplicate todos before limiting', () => {
+    const todos: TodoItem[] = [
+      { tag: 'TODO', text: 'duplicate task', file: 'a.ts', line: 1 },
+      { tag: 'TODO', text: 'duplicate task', file: 'b.ts', line: 2 },
+      { tag: 'TODO', text: 'unique task', file: 'c.ts', line: 3 },
+    ];
+
+    const seen = new Set<string>();
+    const unique = todos.filter(t => {
+      const key = todoKey(t);
+      if (seen.has(key)) return false;
+      seen.add(key);
+      return true;
+    });
+
+    const result = limitTodos(unique, 5);
+
+    expect(result.length).toBe(2);
+    expect(result.map(t => t.text)).toEqual(['duplicate task', 'unique task']);
+  });
+});
+