Add test for if_nametoindex

Author: kamalmarhubi

test/test.rs

@@ -7,6 +7,7 @@ extern crate tempdir;
 extern crate nix_test as nixtest;
 
 mod sys;
+mod test_net;
 mod test_nix_path;
 mod test_stat;
 mod test_unistd;

test/test_net.rs

@@ -0,0 +1,12 @@
+use nix::net::if_::*;
+
+#[cfg(target_os = "linux")]
+const LOOPBACK: &'static [u8] = b"lo";
+
+#[cfg(not(target_os = "linux"))]
+const LOOPBACK: &'static [u8] = b"lo0";
+
+#[test]
+fn test_if_nametoindex() {
+    assert!(if_nametoindex(&LOOPBACK[..]).is_ok());
+}