Fix images paths in several situations related to pages in subdirs (#83)

Author: emad-elsaid

helpers.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"html/template"
+	"path"
 	"slices"
 	"strings"
 	"time"
@@ -160,7 +161,17 @@ func Banner(p Page) string {
 		return ""
 	}
 
-	return string(image.Destination)
+	dest := string(image.Destination)
+	if len(dest) == 0 || dest == "#" {
+		return ""
+	}
+
+	if !(path.IsAbs(dest) || strings.HasPrefix(dest, "http")) {
+		d := path.Dir(p.FileName())
+		dest = path.Join("/", d, dest)
+	}
+
+	return dest
 }
 
 func Emoji(p Page) string {

helpers_test.go

@@ -0,0 +1,75 @@
+package xlog
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"github.com/yuin/goldmark/text"
+)
+
+func TestBanner(t *testing.T) {
+	tcs := []struct {
+		name     string
+		path     string
+		content  string
+		expected string
+	}{
+		{
+			name:     "page in root and image is relative implicitly",
+			path:     "home",
+			content:  "![](image.jpg)",
+			expected: "/image.jpg",
+		},
+		{
+			name:     "page in root and image is relative explicitly",
+			path:     "home",
+			content:  "![](./image.jpg)",
+			expected: "/image.jpg",
+		},
+		{
+			name:     "page in root and image is relative explicitly in subdir",
+			path:     "home",
+			content:  "![](./images/image.jpg)",
+			expected: "/images/image.jpg",
+		},
+		{
+			name:     "page in subdir and image is relative implicitly",
+			path:     "posts/home",
+			content:  "![](image.jpg)",
+			expected: "/posts/image.jpg",
+		},
+		{
+			name:     "page in subdir and image is relative explicitly",
+			path:     "posts/home",
+			content:  "![](./image.jpg)",
+			expected: "/posts/image.jpg",
+		},
+		{
+			name:     "page in subdir and image is relative explicitly in subdir",
+			path:     "posts/home",
+			content:  "![](./images/image.jpg)",
+			expected: "/posts/images/image.jpg",
+		},
+		{
+			name:     "page in subdir and image is relative explicitly in parent",
+			path:     "posts/home",
+			content:  "![](../images/image.jpg)",
+			expected: "/images/image.jpg",
+		},
+	}
+
+	for _, tc := range tcs {
+		t.Run(tc.name, func(t *testing.T) {
+			reader := text.NewReader([]byte(tc.content))
+			p := page{
+				name:       tc.path,
+				lastUpdate: time.Time{},
+				ast:        MarkdownConverter().Parser().Parse(reader),
+				content:    (*Markdown)(&tc.content),
+			}
+
+			require.Equal(t, tc.expected, Banner(&p))
+		})
+	}
+}