diff --git a/util/util_test.go b/util/util_test.go
new file mode 100644
index 0000000..b7bc962
--- /dev/null
+++ b/util/util_test.go
@@ -0,0 +1,36 @@
+package util_test
+
+import "testing"
+import "github.com/hlandau/ncdns/util"
+
+type item struct {
+	input         string
+	expectedHead  string
+	expectedRest  string
+	expectedError error
+}
+
+var items = []item{
+	item{"", "", "", nil},
+	item{"a", "a", "", nil},
+	item{"alpha", "alpha", "", nil},
+	item{"alpha.beta", "beta", "alpha", nil},
+	item{"alpha.beta.gamma", "gamma", "alpha.beta", nil},
+	item{"alpha.beta.gamma.delta", "delta", "alpha.beta.gamma", nil},
+	item{"alpha.beta.gamma.delta.", "delta", "alpha.beta.gamma", nil},
+}
+
+func TestSplitDomainHead(t *testing.T) {
+	for i := range items {
+		head, rest, err := util.SplitDomainHead(items[i].input)
+		if head != items[i].expectedHead {
+			t.Errorf("Input \"%s\": head \"%s\" does not equal expected value \"%s\"", items[i].input, head, items[i].expectedHead)
+		}
+		if rest != items[i].expectedRest {
+			t.Errorf("Input \"%s\": rest \"%s\" does not equal expected value \"%s\"", items[i].input, rest, items[i].expectedRest)
+		}
+		if err != items[i].expectedError {
+			t.Errorf("Input \"%s\": error \"%s\" does not equal expected value \"%s\"", items[i].input, err, items[i].expectedError)
+		}
+	}
+}