@@ -0,0 +1,51 @@
+package htmlformat
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestFormat(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:  "html elements are indented",
+			input: `<ol> <li style="&"> A </li> <li> B </li> </ol> `,
+			expected: `<ol>
+ <li style="&">
+  A
+ </li>
+ <li>
+  B
+ </li>
+</ol>
+`,
+		},
+		{
+			name:     "text fragments are supported",
+			input:    `test 123`,
+			expected: `test 123` + "\n",
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			r := strings.NewReader(test.input)
+			w := new(strings.Builder)
+			if err := Fragment(w, r); err != nil {
+				t.Fatalf("failed to format: %v", err)
+			}
+			if diff := cmp.Diff(test.expected, w.String()); diff != "" {
+				t.Error(diff)
+			}
+		})
+	}
+}