tests: Wait explicitly for vm shutdown w/ the 'wait-timeout' crate

Instead of waiting blindly with fixed amount of sleeping time, we can
use the `wait-timeout` crate to explicitly wait VM shutdown (with a
timeout). It can reduces the execution time of some tests
substantially. Also, this patch increases the `shutdown` timeout for
'test_reboot', which should fix the recent sporadic failures on this
test.

Signed-off-by: Bo Chen <chen.bo@intel.com>

Cargo.lock

@@ -234,6 +234,7 @@ dependencies = [
  "vhost_user_net",
  "vmm",
  "vmm-sys-util",
+ "wait-timeout",
 ]
 
 [[package]]
@@ -1676,6 +1677,15 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "wait-timeout"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f200f5b12eb75f8c1ed65abd4b2db8a6e1b138a20de009dacee265a2498f3f6"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "wasi"
 version = "0.9.0+wasi-snapshot-preview1"

Cargo.toml

@@ -28,6 +28,7 @@ vhost_user_block = { path = "vhost_user_block"}
 vhost_user_net = { path = "vhost_user_net"}
 vmm = { path = "vmm" }
 vmm-sys-util = "0.6.1"
+wait-timeout = "0.2.0"
 
 [build-dependencies]
 clap = { version = "2.33.3", features = ["wrap_help"] }

tests/integration.rs

@@ -31,6 +31,7 @@ mod tests {
     use std::thread;
     use tempdir::TempDir;
     use tempfile::NamedTempFile;
+    use wait_timeout::ChildExt;
 
     lazy_static! {
         static ref NEXT_VM_ID: Mutex<u8> = Mutex::new(1);
@@ -3513,9 +3514,9 @@ mod tests {
                 );
 
                 guest.ssh_command("sudo shutdown -h now").unwrap();
-                thread::sleep(std::time::Duration::new(20, 0));
             });
 
+            let _ = child.wait_timeout(std::time::Duration::from_secs(20));
             let _ = child.kill();
             let output = child.wait_with_output().unwrap();
             handle_child_output(r, &output);
@@ -3607,8 +3608,8 @@ mod tests {
             thread::sleep(std::time::Duration::new(20, 0));
 
             guest.ssh_command("sudo shutdown -h now").unwrap();
-            thread::sleep(std::time::Duration::new(20, 0));
 
+            let _ = child.wait_timeout(std::time::Duration::from_secs(20));
             let _ = child.kill();
             let output = child.wait_with_output().unwrap();
 
@@ -3962,9 +3963,9 @@ mod tests {
                     guest
                         .ssh_command("sudo shutdown -h now")
                         .unwrap_or_default();
-                    thread::sleep(std::time::Duration::new(20, 0));
                 });
 
+                let _ = child.wait_timeout(std::time::Duration::from_secs(40));
                 let _ = child.kill();
                 let output = child.wait_with_output().unwrap();
                 handle_child_output(r, &output);
@@ -4026,9 +4027,9 @@ mod tests {
                 assert_eq!(fd_count_1, fd_count_2);
 
                 guest.ssh_command("sudo shutdown -h now").unwrap();
-                thread::sleep(std::time::Duration::new(20, 0));
             });
 
+            let _ = child.wait_timeout(std::time::Duration::from_secs(20));
             let _ = child.kill();
             let output = child.wait_with_output().unwrap();
             handle_child_output(r, &output);
@@ -5623,9 +5624,9 @@ mod tests {
                     DEFAULT_SSH_TIMEOUT,
                 )
                 .unwrap();
-                thread::sleep(std::time::Duration::new(40, 0));
             });
 
+            let _ = child.wait_timeout(std::time::Duration::from_secs(40));
             let _ = child.kill();
             let output = child.wait_with_output().unwrap();
 
@@ -5720,7 +5721,7 @@ mod tests {
                 .unwrap();
             });
 
-            thread::sleep(std::time::Duration::new(20, 0));
+            let _ = child.wait_timeout(std::time::Duration::from_secs(20));
             let _ = child.kill();
             let output = child.wait_with_output().unwrap();