diff --git a/internal/util_test.go b/internal/util_test.go
new file mode 100644
index 000000000..f090ebaa4
--- /dev/null
+++ b/internal/util_test.go
@@ -0,0 +1,53 @@
+package internal
+
+import (
+	"strings"
+	"testing"
+
+	. "github.com/bsm/ginkgo/v2"
+	. "github.com/bsm/gomega"
+)
+
+func BenchmarkToLowerStd(b *testing.B) {
+	str := "AaBbCcDdEeFfGgHhIiJjKk"
+	for i := 0; i < b.N; i++ {
+		_ = strings.ToLower(str)
+	}
+}
+
+// util.ToLower is 3x faster than strings.ToLower.
+func BenchmarkToLowerInternal(b *testing.B) {
+	str := "AaBbCcDdEeFfGgHhIiJjKk"
+	for i := 0; i < b.N; i++ {
+		_ = ToLower(str)
+	}
+}
+
+func TestToLower(t *testing.T) {
+	It("toLower", func() {
+		str := "AaBbCcDdEeFfGg"
+		Expect(ToLower(str)).To(Equal(strings.ToLower(str)))
+
+		str = "ABCDE"
+		Expect(ToLower(str)).To(Equal(strings.ToLower(str)))
+
+		str = "ABCDE"
+		Expect(ToLower(str)).To(Equal(strings.ToLower(str)))
+
+		str = "abced"
+		Expect(ToLower(str)).To(Equal(strings.ToLower(str)))
+	})
+}
+
+func TestIsLower(t *testing.T) {
+	It("isLower", func() {
+		str := "AaBbCcDdEeFfGg"
+		Expect(isLower(str)).To(BeFalse())
+
+		str = "ABCDE"
+		Expect(isLower(str)).To(BeFalse())
+
+		str = "abcdefg"
+		Expect(isLower(str)).To(BeTrue())
+	})
+}