Add comprehensive test suite for MVP-1 Personal Tracker CLI

Implements 72 tests covering:
- Model tests (Project, Session, Note, Change)
- ProjectService tests (create, get, list, ensure structure)
- SessionService tests (active session management)
- FileStorage tests (read/write operations)
- Complete flow tests (init -> start -> note -> stop -> show)
- Note consolidation tests

Uses pytest with tmp_path fixtures for isolated testing.

tests/test_storage.py

@@ -0,0 +1,193 @@
+"""Tests for FileStorage."""
+
+import json
+from datetime import datetime
+from pathlib import Path
+
+import pytest
+import yaml
+
+from tracker.models import Session
+from tracker.storage import FileStorage
+
+
+class TestReadWriteProjectMeta:
+    """Tests for read/write project meta operations."""
+
+    def test_write_and_read_project_meta(self, tmp_project_dir):
+        """Test writing and reading project meta."""
+        storage = FileStorage(tmp_project_dir)
+        slug = "test-project"
+
+        meta_data = {
+            "id": "test-id",
+            "name": "Test Project",
+            "slug": slug,
+            "description": "A test project",
+            "type": "code",
+            "status": "active",
+            "tags": ["python"],
+            "created_at": datetime(2024, 1, 15, 10, 0, 0).isoformat(),
+            "updated_at": datetime(2024, 1, 15, 10, 0, 0).isoformat(),
+        }
+
+        storage.write_project_meta(slug, meta_data)
+
+        result = storage.read_project_meta(slug)
+        assert result["name"] == "Test Project"
+        assert result["slug"] == slug
+        assert result["type"] == "code"
+
+    def test_read_project_meta_creates_parent_directories(self, tmp_project_dir):
+        """Test that write_project_meta creates parent directories."""
+        storage = FileStorage(tmp_project_dir)
+        slug = "new-project"
+
+        meta_data = {"id": "test-id", "name": "Test", "slug": slug}
+        storage.write_project_meta(slug, meta_data)
+
+        meta_path = tmp_project_dir / slug / "meta" / "project.yaml"
+        assert meta_path.exists()
+
+    def test_read_project_meta_raises_for_nonexistent(self, tmp_project_dir):
+        """Test that reading nonexistent project raises error."""
+        storage = FileStorage(tmp_project_dir)
+
+        with pytest.raises(FileNotFoundError):
+            storage.read_project_meta("nonexistent")
+
+
+class TestAppendToLog:
+    """Tests for append_to_log operations."""
+
+    def test_append_to_log_creates_log_file(self, tmp_project_dir):
+        """Test that append_to_log creates LOG.md if it doesn't exist."""
+        storage = FileStorage(tmp_project_dir)
+        slug = "test-project"
+
+        # Create project directory first
+        (tmp_project_dir / slug).mkdir(parents=True)
+
+        storage.append_to_log(slug, "# Test Log Entry\n")
+
+        log_path = tmp_project_dir / slug / "LOG.md"
+        assert log_path.exists()
+
+    def test_append_to_log_appends_content(self, tmp_project_dir):
+        """Test that append_to_log appends content to LOG.md."""
+        storage = FileStorage(tmp_project_dir)
+        slug = "test-project"
+
+        # Create project directory first
+        (tmp_project_dir / slug).mkdir(parents=True)
+
+        storage.append_to_log(slug, "# First Entry\n")
+        storage.append_to_log(slug, "# Second Entry\n")
+
+        content = storage.read_log(slug)
+        assert "# First Entry" in content
+        assert "# Second Entry" in content
+
+    def test_read_log_returns_empty_string_for_nonexistent(self, tmp_project_dir):
+        """Test that read_log returns empty string for nonexistent log."""
+        storage = FileStorage(tmp_project_dir)
+
+        result = storage.read_log("nonexistent")
+        assert result == ""
+
+
+class TestActiveSessionStorage:
+    """Tests for active session storage operations."""
+
+    def test_write_and_read_active_session(self, tmp_project_dir, mock_session):
+        """Test writing and reading active session."""
+        storage = FileStorage(tmp_project_dir)
+
+        session_data = mock_session.model_dump(mode="json")
+        session_data["started_at"] = mock_session.started_at.isoformat()
+        if mock_session.ended_at:
+            session_data["ended_at"] = mock_session.ended_at.isoformat()
+
+        storage.write_active_session(session_data)
+
+        result = storage.read_active_session()
+        assert result is not None
+        assert result["id"] == mock_session.id
+
+    def test_read_active_session_returns_none_when_not_exists(self, tmp_project_dir):
+        """Test that read_active_session returns None when file doesn't exist."""
+        storage = FileStorage(tmp_project_dir)
+
+        result = storage.read_active_session()
+        assert result is None
+
+    def test_delete_active_session(self, tmp_project_dir, mock_session):
+        """Test deleting active session."""
+        storage = FileStorage(tmp_project_dir)
+
+        session_data = mock_session.model_dump(mode="json")
+        session_data["started_at"] = mock_session.started_at.isoformat()
+        storage.write_active_session(session_data)
+
+        storage.delete_active_session()
+
+        result = storage.read_active_session()
+        assert result is None
+
+    def test_delete_active_session_when_not_exists(self, tmp_project_dir):
+        """Test deleting active session when it doesn't exist doesn't error."""
+        storage = FileStorage(tmp_project_dir)
+
+        storage.delete_active_session()
+
+
+class TestProjectExistence:
+    """Tests for project existence checks."""
+
+    def test_project_exists_returns_true_for_existing_project(self, tmp_project_dir):
+        """Test that project_exists returns True for existing project."""
+        storage = FileStorage(tmp_project_dir)
+        slug = "test-project"
+
+        (tmp_project_dir / slug).mkdir()
+
+        assert storage.project_exists(slug) is True
+
+    def test_project_exists_returns_false_for_nonexistent(self, tmp_project_dir):
+        """Test that project_exists returns False for nonexistent project."""
+        storage = FileStorage(tmp_project_dir)
+
+        assert storage.project_exists("nonexistent") is False
+
+
+class TestListProjects:
+    """Tests for listing projects."""
+
+    def test_list_projects_returns_all_projects(self, tmp_project_dir):
+        """Test that list_projects returns all project slugs."""
+        storage = FileStorage(tmp_project_dir)
+
+        (tmp_project_dir / "project-1").mkdir()
+        (tmp_project_dir / "project-2").mkdir()
+
+        projects = storage.list_projects()
+        assert "project-1" in projects
+        assert "project-2" in projects
+
+    def test_list_projects_excludes_hidden_directories(self, tmp_project_dir):
+        """Test that list_projects excludes hidden directories."""
+        storage = FileStorage(tmp_project_dir)
+
+        (tmp_project_dir / "project-1").mkdir()
+        (tmp_project_dir / ".hidden").mkdir()
+
+        projects = storage.list_projects()
+        assert "project-1" in projects
+        assert ".hidden" not in projects
+
+    def test_list_projects_returns_empty_list_when_no_projects(self, tmp_project_dir):
+        """Test that list_projects returns empty list when no projects exist."""
+        storage = FileStorage(tmp_project_dir)
+
+        projects = storage.list_projects()
+        assert projects == []