tests: pids: add a proper test

Signed-off-by: Levente Kurusa <lkurusa@acm.org>

Cargo.toml

@@ -9,3 +9,7 @@ version = "0.0.1"
 authors = ["Levente Kurusa <lkurusa@acm.org>"]
 
 [dependencies]
+
+[dev-dependencies]
+nix = "0.11.0"
+libc = "0.2.43"

tests/pids.rs

@@ -1,8 +1,17 @@
 //! Integration tests about the pids subsystem
 extern crate cgroups;
-
-use cgroups::{Cgroup, Resources, PidResources};
+use cgroups::{CgroupPid, Cgroup, Resources, PidResources};
 use cgroups::pid::{PidController, PidMax};
+use cgroups::Controller;
+
+extern crate nix;
+use nix::unistd::{Pid, fork, ForkResult};
+use nix::sys::wait::{waitpid, WaitStatus};
+
+extern crate libc;
+use libc::pid_t;
+
+use std::thread;
 
 #[test]
 fn create_and_delete_cgroup() {
@@ -17,9 +26,9 @@ fn create_and_delete_cgroup() {
 }
 
 #[test]
-fn test_pid_pids_current_is_zero() {
+fn test_pids_current_is_zero() {
     let hier = cgroups::hierarchies::V1::new();
-    let cg = Cgroup::new(&hier, String::from("test_pid_pids_current_is_zero"));
+    let cg = Cgroup::new(&hier, String::from("test_pids_current_is_zero"));
     {
         let pidcontroller: &PidController = cg.controller_of().unwrap();
         assert_eq!(pidcontroller.get_pid_current(), 0);
@@ -28,12 +37,59 @@ fn test_pid_pids_current_is_zero() {
 }
 
 #[test]
-fn test_pid_pids_events_is_zero() {
+fn test_pids_events_is_zero() {
     let hier = cgroups::hierarchies::V1::new();
-    let cg = Cgroup::new(&hier, String::from("test_pid_pids_events_is_zero"));
+    let cg = Cgroup::new(&hier, String::from("test_pids_events_is_zero"));
     {
         let pidcontroller: &PidController = cg.controller_of().unwrap();
         assert_eq!(pidcontroller.get_pid_events(), 0);
     }
     cg.delete();
 }
+
+#[test]
+fn test_pid_events_is_not_zero() {
+    let hier = cgroups::hierarchies::V1::new();
+    let cg = Cgroup::new(&hier, String::from("test_pid_events_is_not_zero"));
+    {
+        let pids: &PidController = cg.controller_of().unwrap();
+        let before = pids.get_pid_events();
+
+        match fork() {
+            Ok(ForkResult::Parent { child, .. }) => {
+                // move the process into the control group
+                pids.add_task(&(pid_t::from(child) as u64).into());
+
+                println!("added task to cg: {:?}", child);
+
+                // Set limit to one
+                pids.set_pid_max(PidMax::Value(1));
+                println!("err = {:?}", pids.get_pid_max());
+
+                // wait on the child
+                let res = waitpid(child, None);
+                if let Ok(WaitStatus::Exited(_, e)) = res {
+                    assert_eq!(e, 0i32);
+                } else {
+                    panic!("found result: {:?}", res);
+                }
+
+                // Check pids.events
+                assert_eq!(pids.get_pid_events(), before + 1);
+            },
+            Ok(ForkResult::Child) => {
+                loop {
+                    if pids.get_pid_max() == Some(PidMax::Value(1)) {
+                        if let Err(_) = fork() {
+                            unsafe { libc::exit(0) };
+                        } else {
+                            unsafe { libc::exit(1) };
+                        }
+                    }
+                }
+            },
+            Err(_) => panic!("failed to fork"),
+        }
+    }
+    cg.delete();
+}