diff --git a/cmd/sanderling/replay_test.go b/cmd/sanderling/replay_test.go
index ab01d68..1bcdd40 100644
--- a/cmd/sanderling/replay_test.go
+++ b/cmd/sanderling/replay_test.go
@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"io"
+	"net"
 	"strings"
 	"testing"
 )
@@ -34,6 +35,25 @@ func TestParseReplayArgs_RejectsTooManyPositional(t *testing.T) {
 	}
 }
 
+func TestBuildBrowseURL(t *testing.T) {
+	address := &net.TCPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 8080}
+	cases := []struct {
+		name       string
+		deepLinkID string
+		want       string
+	}{
+		{"root", "", "http://127.0.0.1:8080/"},
+		{"deep link", "20240101-120000", "http://127.0.0.1:8080/runs/20240101-120000"},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if got := buildBrowseURL(address, c.deepLinkID); got != c.want {
+				t.Errorf("buildBrowseURL(%q) = %q, want %q", c.deepLinkID, got, c.want)
+			}
+		})
+	}
+}
+
 func TestRun_HelpListsReplayCommand(t *testing.T) {
 	var stdout bytes.Buffer
 	if err := run([]string{"sanderling"}, &stdout, io.Discard); err != nil {