Fix zero-items bug with getPageInfo

src/website/pagination.go

@@ -3,6 +3,8 @@ package website
 import (
 	"math"
 	"strconv"
+
+	"git.handmade.network/hmn/hmn/src/utils"
 )
 
 func getPageInfo(
@@ -14,7 +16,7 @@ func getPageInfo(
 	totalPages int,
 	ok bool,
 ) {
-	totalPages = int(math.Ceil(float64(totalItems) / float64(itemsPerPage)))
+	totalPages = utils.IntMax(1, int(math.Ceil(float64(totalItems)/float64(itemsPerPage))))
 	ok = true
 
 	page = 1

src/website/pagination_test.go

@@ -0,0 +1,36 @@
+package website
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetPageInfo(t *testing.T) {
+	items := []struct {
+		name                string
+		pageParam           string
+		totalItems, perPage int
+		page, totalPages    int
+		ok                  bool
+	}{
+		{"good, no param", "", 85, 10, 1, 9, true},
+		{"good", "2", 85, 10, 2, 9, true},
+		{"too big", "10", 85, 10, 0, 0, false},
+		{"too small", "0", 85, 10, 0, 0, false},
+		{"pizza", "pizza", 85, 10, 0, 0, false},
+		{"zero items, no param", "", 0, 10, 1, 1, true}, // should go to page 1
+		{"zero items, page 1", "1", 0, 10, 1, 1, true},
+		{"zero items, too big", "2", 0, 10, 0, 0, false},
+		{"zero items, too small", "0", 0, 10, 0, 0, false},
+	}
+
+	for _, item := range items {
+		t.Run(item.name, func(t *testing.T) {
+			page, totalPages, ok := getPageInfo(item.pageParam, item.totalItems, item.perPage)
+			assert.Equal(t, item.page, page)
+			assert.Equal(t, item.totalPages, totalPages)
+			assert.Equal(t, item.ok, ok)
+		})
+	}
+}