diff --git a/unix/mmap_unix_test.go b/unix/mmap_unix_test.go
new file mode 100644
index 0000000..01f7783
--- /dev/null
+++ b/unix/mmap_unix_test.go
@@ -0,0 +1,22 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd
+
+package syscall_test
+
+import (
+	"syscall"
+	"testing"
+)
+
+func TestMmap(t *testing.T) {
+	b, err := syscall.Mmap(-1, 0, syscall.Getpagesize(), syscall.PROT_NONE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
+	if err != nil {
+		t.Fatalf("Mmap: %v", err)
+	}
+	if err := syscall.Munmap(b); err != nil {
+		t.Fatalf("Munmap: %v", err)
+	}
+}