feat(taskflow): add core task API, storage persistence, csv export, stats page, and test coverage

tests/test_repository_recovery.py

@@ -0,0 +1,102 @@
+from __future__ import annotations
+
+import json
+from datetime import UTC, datetime
+from uuid import uuid4
+
+from app.storage import DATA_FORMAT_VERSION, StoredTask
+from app.storage.repository import JsonFileTaskRepository
+
+
+def make_task(title: str = "Task") -> StoredTask:
+    return StoredTask(
+        id=uuid4(),
+        title=title,
+        created_at=datetime.now(UTC),
+        started_at=None,
+        done_at=None,
+    )
+
+
+def test_corrupted_json_triggers_backup_and_reset(tmp_path):
+    file_path = tmp_path / "tasks.json"
+    file_path.write_text('{"version": 1, "tasks": [', encoding="utf-8")
+
+    repo = JsonFileTaskRepository(file_path)
+
+    assert repo.list_tasks() == []
+
+    backups = list(tmp_path.glob("tasks.json.corrupted*"))
+    assert len(backups) == 1
+    assert backups[0].read_text(encoding="utf-8") == '{"version": 1, "tasks": ['
+
+    restored = json.loads(file_path.read_text(encoding="utf-8"))
+    assert restored["version"] == DATA_FORMAT_VERSION
+    assert restored["tasks"] == []
+
+
+def test_invalid_schema_triggers_backup_and_reset(tmp_path):
+    file_path = tmp_path / "tasks.json"
+    file_path.write_text(
+        json.dumps(
+            {
+                "version": 1,
+                "tasks": [
+                    {
+                        "id": str(uuid4()),
+                        "created_at": datetime.now(UTC).isoformat(),
+                    },
+                ],
+            },
+        ),
+        encoding="utf-8",
+    )
+
+    repo = JsonFileTaskRepository(file_path)
+
+    assert repo.list_tasks() == []
+    backups = list(tmp_path.glob("tasks.json.corrupted*"))
+    assert len(backups) == 1
+
+
+def test_repository_remains_writable_after_recovery(tmp_path):
+    file_path = tmp_path / "tasks.json"
+    file_path.write_text("not valid json", encoding="utf-8")
+    repo = JsonFileTaskRepository(file_path)
+
+    task = make_task("Recovered")
+    repo.create_task(task)
+
+    assert repo.list_tasks() == [task]
+
+
+def test_unsupported_version_creates_backup_and_resets_state(tmp_path):
+    file_path = tmp_path / "tasks.json"
+    file_path.write_text(
+        json.dumps({"version": 999, "tasks": []}),
+        encoding="utf-8",
+    )
+
+    repo = JsonFileTaskRepository(file_path)
+
+    assert repo.list_tasks() == []
+    backups = list(tmp_path.glob("tasks.json.corrupted*"))
+    assert len(backups) == 1
+
+    restored = json.loads(file_path.read_text(encoding="utf-8"))
+    assert restored["version"] == DATA_FORMAT_VERSION
+    assert restored["tasks"] == []
+
+
+def test_restart_after_corrupted_persisted_state_does_not_crash(tmp_path):
+    file_path = tmp_path / "tasks.json"
+    repo_1 = JsonFileTaskRepository(file_path)
+    repo_1.create_task(make_task("Initial"))
+
+    file_path.write_text("{broken", encoding="utf-8")
+
+    repo_2 = JsonFileTaskRepository(file_path)
+
+    assert repo_2.list_tasks() == []
+    assert len(list(tmp_path.glob("tasks.json.corrupted*"))) == 1
+