1 files changed, 187 insertions, 0 deletions
diff --git a/internal/api/google_tasks_test.go b/internal/api/google_tasks_test.go
new file mode 100644
index 0000000..fbfdd63
--- /dev/null
+++ b/internal/api/google_tasks_test.go
@@ -0,0 +1,187 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"google.golang.org/api/option"
+	gtasks "google.golang.org/api/tasks/v1"
+)
+
+func newTestGoogleTasksClient(t *testing.T, server *httptest.Server, tasklistID string, tz *time.Location) *GoogleTasksClient {
+	t.Helper()
+	if tz == nil {
+		tz = time.UTC
+	}
+	httpClient := &http.Client{Transport: &redirectingTransport{server: server}}
+	srv, err := gtasks.NewService(context.Background(),
+		option.WithHTTPClient(httpClient),
+		option.WithoutAuthentication(),
+	)
+	if err != nil {
+		t.Fatalf("failed to create test tasks service: %v", err)
+	}
+	return &GoogleTasksClient{
+		srv:        srv,
+		tasklistID: tasklistID,
+		displayTZ:  tz,
+	}
+}
+
+func tasksAPIResponse(items []map[string]interface{}) string {
+	b, _ := json.Marshal(map[string]interface{}{
+		"kind":  "tasks#tasks",
+		"items": items,
+	})
+	return string(b)
+}
+
+// newTasksServer returns an httptest.Server that serves a fixed tasks JSON body.
+func newTasksServer(body string) *httptest.Server {
+	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if !strings.Contains(r.URL.Path, "/lists/") {
+			http.NotFound(w, r)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(body))
+	}))
+}
+
+// --- GetTasksByDateRange boundary tests ---
+
+func TestGetTasksByDateRange_StartBoundaryIncluded(t *testing.T) {
+	// A task due exactly on the start date should be included (inclusive lower bound).
+	start := time.Date(2026, 3, 17, 0, 0, 0, 0, time.UTC)
+	end := time.Date(2026, 3, 20, 0, 0, 0, 0, time.UTC)
+
+	body := tasksAPIResponse([]map[string]interface{}{
+		{
+			"id":      "task-start",
+			"title":   "Task on start date",
+			"status":  "needsAction",
+			"due":     "2026-03-17T00:00:00Z",
+			"updated": "2026-03-17T00:00:00Z",
+		},
+	})
+	server := newTasksServer(body)
+	defer server.Close()
+
+	client := newTestGoogleTasksClient(t, server, "@default", time.UTC)
+	tasks, err := client.GetTasksByDateRange(context.Background(), start, end)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(tasks) != 1 {
+		t.Fatalf("expected 1 task (start boundary included), got %d", len(tasks))
+	}
+	if tasks[0].ID != "task-start" {
+		t.Errorf("expected task-start, got %s", tasks[0].ID)
+	}
+}
+
+func TestGetTasksByDateRange_EndBoundaryExcluded(t *testing.T) {
+	// A task due exactly on the end date should be excluded (exclusive upper bound).
+	start := time.Date(2026, 3, 17, 0, 0, 0, 0, time.UTC)
+	end := time.Date(2026, 3, 20, 0, 0, 0, 0, time.UTC)
+
+	body := tasksAPIResponse([]map[string]interface{}{
+		{
+			"id":      "task-end",
+			"title":   "Task on end date",
+			"status":  "needsAction",
+			"due":     "2026-03-20T00:00:00Z",
+			"updated": "2026-03-17T00:00:00Z",
+		},
+	})
+	server := newTasksServer(body)
+	defer server.Close()
+
+	client := newTestGoogleTasksClient(t, server, "@default", time.UTC)
+	tasks, err := client.GetTasksByDateRange(context.Background(), start, end)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(tasks) != 0 {
+		t.Fatalf("expected 0 tasks (end boundary excluded), got %d", len(tasks))
+	}
+}
+
+func TestGetTasksByDateRange_NoDueDateAlwaysIncluded(t *testing.T) {
+	// Tasks without a due date are always included regardless of the range.
+	start := time.Date(2026, 3, 17, 0, 0, 0, 0, time.UTC)
+	end := time.Date(2026, 3, 20, 0, 0, 0, 0, time.UTC)
+
+	body := tasksAPIResponse([]map[string]interface{}{
+		{
+			"id":      "task-no-due",
+			"title":   "No due date",
+			"status":  "needsAction",
+			"updated": "2026-03-17T00:00:00Z",
+			// no "due" field
+		},
+	})
+	server := newTasksServer(body)
+	defer server.Close()
+
+	client := newTestGoogleTasksClient(t, server, "@default", time.UTC)
+	tasks, err := client.GetTasksByDateRange(context.Background(), start, end)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(tasks) != 1 {
+		t.Fatalf("expected 1 task (no due date always included), got %d", len(tasks))
+	}
+	if tasks[0].DueDate != nil {
+		t.Errorf("expected nil DueDate, got %v", tasks[0].DueDate)
+	}
+}
+
+func TestGetTasksByDateRange_OutOfRangeExcluded(t *testing.T) {
+	// A task before start or after end should be excluded.
+	start := time.Date(2026, 3, 17, 0, 0, 0, 0, time.UTC)
+	end := time.Date(2026, 3, 20, 0, 0, 0, 0, time.UTC)
+
+	body := tasksAPIResponse([]map[string]interface{}{
+		{
+			"id":      "task-before",
+			"title":   "Task before range",
+			"status":  "needsAction",
+			"due":     "2026-03-16T00:00:00Z",
+			"updated": "2026-03-17T00:00:00Z",
+		},
+		{
+			"id":      "task-after",
+			"title":   "Task after range",
+			"status":  "needsAction",
+			"due":     "2026-03-21T00:00:00Z",
+			"updated": "2026-03-17T00:00:00Z",
+		},
+		{
+			"id":      "task-in-range",
+			"title":   "Task in range",
+			"status":  "needsAction",
+			"due":     "2026-03-18T00:00:00Z",
+			"updated": "2026-03-17T00:00:00Z",
+		},
+	})
+	server := newTasksServer(body)
+	defer server.Close()
+
+	client := newTestGoogleTasksClient(t, server, "@default", time.UTC)
+	tasks, err := client.GetTasksByDateRange(context.Background(), start, end)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(tasks) != 1 {
+		t.Fatalf("expected 1 task (only in-range), got %d", len(tasks))
+	}
+	if tasks[0].ID != "task-in-range" {
+		t.Errorf("expected task-in-range, got %s", tasks[0].ID)
+	}
+}