Support for images

telegram_helpers_test.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/go-telegram/bot/models"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLargestPhotoSize(t *testing.T) {
+	cases := []struct {
+		name       string
+		photos     []models.PhotoSize
+		wantFileID string
+	}{
+		{
+			name: "ascending sizes — last is largest",
+			photos: []models.PhotoSize{
+				{FileID: "thumb", Width: 90, Height: 90},
+				{FileID: "small", Width: 320, Height: 320},
+				{FileID: "full", Width: 1280, Height: 720},
+			},
+			wantFileID: "full",
+		},
+		{
+			name: "descending sizes — first is largest",
+			photos: []models.PhotoSize{
+				{FileID: "full", Width: 1280, Height: 720},
+				{FileID: "small", Width: 320, Height: 320},
+				{FileID: "thumb", Width: 90, Height: 90},
+			},
+			wantFileID: "full",
+		},
+		{
+			name: "single photo",
+			photos: []models.PhotoSize{
+				{FileID: "solo", Width: 800, Height: 600},
+			},
+			wantFileID: "solo",
+		},
+		{
+			name:       "empty slice returns zero value (caller guards upstream)",
+			photos:     []models.PhotoSize{},
+			wantFileID: "",
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := largestPhotoSize(tc.photos)
+			assert.Equal(t, tc.wantFileID, got.FileID)
+		})
+	}
+}