Self-contained, skip-friendly lab starting points (#103)

Co-authored-by: claude <claude@jpaul.io>
Co-committed-by: claude <claude@jpaul.io>

modules/21-skills-teaching-the-ai-your-playbook/lab/start/test_tasks.py

@@ -0,0 +1,44 @@
+"""Test suite for the tasks-app. Run from this folder with:
+
+    python -m unittest
+
+Your "add a command" skill should ADD a test here for every new command. The point is to assert
+intended behavior, not just that nothing crashed.
+"""
+
+import unittest
+
+from tasks import TaskList
+
+
+class TestTaskBasics(unittest.TestCase):
+    def test_add_appends_a_task(self):
+        tl = TaskList()
+        tl.add("write the skill")
+        self.assertEqual(len(tl.tasks), 1)
+        self.assertEqual(tl.tasks[0].title, "write the skill")
+        self.assertFalse(tl.tasks[0].done)
+
+    def test_complete_marks_done(self):
+        tl = TaskList()
+        tl.add("a")
+        tl.complete(0)
+        self.assertTrue(tl.tasks[0].done)
+
+    def test_pending_excludes_completed(self):
+        tl = TaskList()
+        tl.add("a")
+        tl.add("b")
+        tl.complete(0)
+        self.assertEqual([t.title for t in tl.pending()], ["b"])
+
+    def test_pending_count_ignores_done(self):
+        tl = TaskList()
+        tl.add("a")
+        tl.add("b")
+        tl.complete(0)
+        self.assertEqual(tl.pending_count(), 1)
+
+
+if __name__ == "__main__":
+    unittest.main()