diff --git a/swift/swift_internal_test.go b/swift/swift_internal_test.go
new file mode 100644
index 000000000..de95a4c67
--- /dev/null
+++ b/swift/swift_internal_test.go
@@ -0,0 +1,25 @@
+package swift
+
+import "testing"
+
+func TestInternalUrlEncode(t *testing.T) {
+	for _, test := range []struct {
+		in   string
+		want string
+	}{
+		{"", ""},
+		{"abcdefghijklmopqrstuvwxyz", "abcdefghijklmopqrstuvwxyz"},
+		{"ABCDEFGHIJKLMOPQRSTUVWXYZ", "ABCDEFGHIJKLMOPQRSTUVWXYZ"},
+		{"0123456789", "0123456789"},
+		{"abc/ABC/123", "abc/ABC/123"},
+		{"   ", "%20%20%20"},
+		{"&", "%26"},
+		{"ߣ", "%C3%9F%C2%A3"},
+		{"Vidéo Potato Sausage?&£.mkv", "Vid%C3%A9o%20Potato%20Sausage%3F%26%C2%A3.mkv"},
+	} {
+		got := urlEncode(test.in)
+		if got != test.want {
+			t.Logf("%q: want %q got %q", test.in, test.want, got)
+		}
+	}
+}