ci: add deployment workflow and automated tests

tests/test_todoupdate.py

@@ -0,0 +1,23 @@
+import pytest
+from pydantic import ValidationError
+
+from main import todoupdate
+
+
+def test_todoupdate_rejects_empty_update() -> None:
+    with pytest.raises(ValidationError):
+        todoupdate()
+
+def test_todoupdate_accepts_provided_value() -> None:
+    update_data = todoupdate(
+            task = "学习测试单元",
+            completion = True,
+        )
+
+    assert update_data.task == "学习测试单元"
+
+def test_todoupdate_accepts_task_only() -> None:
+    update_data = todoupdate(task="修改后的任务")
+
+    assert update_data.task == "修改后的任务"
+    assert update_data.completion is None