sys_util: Use expect_err instead of panicking

Use expect_err in the unix_seqpacket_zero_timeout test instead of
`#[should_panic]` as the panic is causing a memory leak.

BUG=chromium:950576
TEST=`USE=asan FEATURES=test emerge-amd64-generic sys_util`

Change-Id: I7a42bbbc741a84398989393e3294747cd01cee14
Reviewed-on: https://chromium-review.googlesource.com/1558933
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/sys_util/src/net.rs b/sys_util/src/net.rs
index 46d8689..36b696e 100644
--- a/sys_util/src/net.rs
+++ b/sys_util/src/net.rs
@@ -515,12 +515,11 @@ mod tests {
     }
 
     #[test]
-    #[should_panic]
     fn unix_seqpacket_zero_timeout() {
         let (s1, _s2) = UnixSeqpacket::pair().expect("failed to create socket pair");
         // Timeouts less than a microsecond are too small and round to zero.
         s1.set_read_timeout(Some(Duration::from_nanos(10)))
-            .expect("failed to set read timeout for socket");
+            .expect_err("successfully set zero timeout");
     }
 
     #[test]