diff --git a/packages/typeutils/unsafe_test.go b/packages/typeutils/unsafe_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..d28a5c06f411c754399117d161cc0e7585cc5a19
--- /dev/null
+++ b/packages/typeutils/unsafe_test.go
@@ -0,0 +1,92 @@
+package typeutils
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+var testStrings = []string{
+	"",
+	" ",
+	"test",
+	"こんにちは、 世界",
+	strings.Repeat(" ", 10),
+	strings.Repeat(" ", 100),
+	strings.Repeat(" ", 10000),
+	strings.Repeat(" ", 1000000),
+}
+
+func TestBytesToString(t *testing.T) {
+	for _, expected := range testStrings {
+		arg := []byte(expected)
+		actual := BytesToString(arg)
+		if actual != expected {
+			t.Errorf("BytesToString(%q) = %q but expected %q", arg, actual, expected)
+		}
+	}
+}
+
+func TestStringToBytes(t *testing.T) {
+	for _, arg := range testStrings {
+		expected := []byte(arg)
+		actual := StringToBytes(arg)
+		if !bytes.Equal(actual, expected) {
+			t.Errorf("Bytes(%q) = %q but expected %q", arg, actual, expected)
+		}
+	}
+}
+
+func TestNil(t *testing.T) {
+	actual := BytesToString(nil)
+	expected := ""
+	if actual != expected {
+		t.Errorf("String(nil) = %q but expected %q", actual, expected)
+	}
+}
+
+func createTestBytes() [][]byte {
+	result := make([][]byte, len(testStrings))
+	for i, str := range testStrings {
+		result[i] = []byte(str)
+	}
+	return result
+}
+
+func BenchmarkNativeBytesToString(b *testing.B) {
+	testBytes := createTestBytes()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		for _, bs := range testBytes {
+			_ = string(bs)
+		}
+	}
+}
+
+func BenchmarkUnsafeBytesToString(b *testing.B) {
+	testBytes := createTestBytes()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		for _, bs := range testBytes {
+			_ = BytesToString(bs)
+		}
+	}
+}
+
+func BenchmarkNativeStringToBytes(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, str := range testStrings {
+			_ = []byte(str)
+		}
+	}
+}
+
+func BenchmarkUnsafeStringToBytes(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, str := range testStrings {
+			_ = StringToBytes(str)
+		}
+	}
+}