Add comprehensive test coverage across packages

New test files:
- api/http_test.go: HTTP client and error handling tests
- config/config_test.go: Configuration loading and validation tests
- middleware/security_test.go: Security middleware tests
- models/atom_test.go: Atom model and conversion tests

Expanded test coverage:
- api/todoist_test.go: Todoist API client tests
- api/trello_test.go: Trello API client tests
- auth/auth_test.go: Authentication and CSRF tests
- handlers/timeline_logic_test.go: Timeline building logic tests
- store/sqlite_test.go: SQLite store operations tests

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 183 insertions, 0 deletions

diff --git a/internal/api/todoist_test.go b/internal/api/todoist_test.go
index 7bbcc1e..f7ca719 100644
--- a/internal/api/todoist_test.go
+++ b/internal/api/todoist_test.go
@@ -246,3 +246,186 @@ func TestTodoistClient_GetProjects(t *testing.T) {
 		t.Errorf("Project 2 mismatch: got ID=%s Name=%s", projects[1].ID, projects[1].Name)
 	}
 }
+
+func TestTodoistClient_GetTasks(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "GET" {
+			t.Errorf("Expected GET, got %s", r.Method)
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+
+		// GetTasks also calls GetProjects internally
+		if r.URL.Path == "/projects" {
+			response := []todoistProjectResponse{
+				{ID: "proj-1", Name: "Project 1"},
+			}
+			json.NewEncoder(w).Encode(response)
+			return
+		}
+
+		if r.URL.Path == "/tasks" {
+			response := []todoistTaskResponse{
+				{ID: "task-1", Content: "Task 1", ProjectID: "proj-1", CreatedAt: time.Now().Format(time.RFC3339)},
+				{ID: "task-2", Content: "Task 2", ProjectID: "proj-1", CreatedAt: time.Now().Format(time.RFC3339)},
+			}
+			json.NewEncoder(w).Encode(response)
+			return
+		}
+
+		t.Errorf("Unexpected path: %s", r.URL.Path)
+	}))
+	defer server.Close()
+
+	client := newTestTodoistClient(server.URL, "test-key")
+	tasks, err := client.GetTasks(context.Background())
+	if err != nil {
+		t.Fatalf("GetTasks failed: %v", err)
+	}
+
+	if len(tasks) != 2 {
+		t.Errorf("Expected 2 tasks, got %d", len(tasks))
+	}
+}
+
+func TestTodoistClient_ReopenTask(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "POST" {
+			t.Errorf("Expected POST, got %s", r.Method)
+		}
+		expectedPath := "/tasks/task-123/reopen"
+		if r.URL.Path != expectedPath {
+			t.Errorf("Expected path %s, got %s", expectedPath, r.URL.Path)
+		}
+
+		w.WriteHeader(http.StatusNoContent)
+	}))
+	defer server.Close()
+
+	client := newTestTodoistClient(server.URL, "test-key")
+	err := client.ReopenTask(context.Background(), "task-123")
+	if err != nil {
+		t.Fatalf("ReopenTask failed: %v", err)
+	}
+}
+
+func TestTodoistClient_UpdateTask(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "POST" {
+			t.Errorf("Expected POST, got %s", r.Method)
+		}
+		expectedPath := "/tasks/task-123"
+		if r.URL.Path != expectedPath {
+			t.Errorf("Expected path %s, got %s", expectedPath, r.URL.Path)
+		}
+
+		var payload map[string]interface{}
+		json.NewDecoder(r.Body).Decode(&payload)
+		if payload["content"] != "Updated Content" {
+			t.Errorf("Expected content 'Updated Content', got %v", payload["content"])
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]string{"id": "task-123"})
+	}))
+	defer server.Close()
+
+	client := newTestTodoistClient(server.URL, "test-key")
+	err := client.UpdateTask(context.Background(), "task-123", map[string]interface{}{"content": "Updated Content"})
+	if err != nil {
+		t.Fatalf("UpdateTask failed: %v", err)
+	}
+}
+
+func TestTodoistClient_Sync(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "POST" {
+			t.Errorf("Expected POST, got %s", r.Method)
+		}
+		if r.URL.Path != "/sync" {
+			t.Errorf("Expected path /sync, got %s", r.URL.Path)
+		}
+
+		response := TodoistSyncResponse{
+			SyncToken: "new-sync-token",
+			FullSync:  true,
+			Items: []SyncItemResponse{
+				{ID: "item-1", Content: "Item 1", ProjectID: "proj-1"},
+			},
+			Projects: []SyncProjectResponse{
+				{ID: "proj-1", Name: "Project 1"},
+			},
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(response)
+	}))
+	defer server.Close()
+
+	client := newTestTodoistClient(server.URL, "test-key")
+	resp, err := client.Sync(context.Background(), "*")
+	if err != nil {
+		t.Fatalf("Sync failed: %v", err)
+	}
+
+	if resp.SyncToken != "new-sync-token" {
+		t.Errorf("Expected sync token 'new-sync-token', got '%s'", resp.SyncToken)
+	}
+	if len(resp.Items) != 1 {
+		t.Errorf("Expected 1 item, got %d", len(resp.Items))
+	}
+}
+
+func TestConvertSyncItemsToTasks(t *testing.T) {
+	projects := map[string]string{
+		"proj-1": "Project 1",
+	}
+
+	items := []SyncItemResponse{
+		{
+			ID:          "item-1",
+			Content:     "Task 1",
+			Description: "Description 1",
+			ProjectID:   "proj-1",
+			Priority:    3,
+			Labels:      []string{"label1"},
+		},
+		{
+			ID:          "item-2",
+			Content:     "Completed Task",
+			ProjectID:   "proj-1",
+			IsCompleted: true,
+		},
+	}
+
+	tasks := ConvertSyncItemsToTasks(items, projects)
+
+	// Should skip completed task
+	if len(tasks) != 1 {
+		t.Errorf("Expected 1 task (excluding completed), got %d", len(tasks))
+	}
+
+	if tasks[0].ID != "item-1" {
+		t.Errorf("Expected task ID 'item-1', got '%s'", tasks[0].ID)
+	}
+	if tasks[0].ProjectName != "Project 1" {
+		t.Errorf("Expected project name 'Project 1', got '%s'", tasks[0].ProjectName)
+	}
+}
+
+func TestBuildProjectMapFromSync(t *testing.T) {
+	projects := []SyncProjectResponse{
+		{ID: "proj-1", Name: "Project 1"},
+		{ID: "proj-2", Name: "Project 2"},
+	}
+
+	projectMap := BuildProjectMapFromSync(projects)
+
+	if len(projectMap) != 2 {
+		t.Errorf("Expected 2 projects in map, got %d", len(projectMap))
+	}
+
+	if projectMap["proj-1"] != "Project 1" {
+		t.Errorf("Expected 'Project 1', got '%s'", projectMap["proj-1"])
+	}
+}