Update TestRestartMonitor expected time check

Use the time for the last non-running status to determine
whether the restart did not occur as expected. The
current timestamp only accounts for when the running
status was seen, however, the restart would have always
occurred in between the previous check and latest check.
Therefore, it makes more sense to use the previous check
to determine whether a failure was seen from the restart
monitor not restarting as expected.

Signed-off-by: Derek McGowan <derek@mcg.dev>

integration/client/restart_monitor_test.go

@@ -173,10 +173,9 @@ version = 2
 	}
 
 	begin := time.Now()
+	lastCheck := begin
 
-	// The restart is "truly" expected after (interval + epsilon), but due to some flakiness in CI, we give it a bit extra time.
-	// Specifically, we give an extra "grace period" of (count / 2) seconds.
-	expected := begin.Add(interval).Add(epsilon * (count / 2))
+	expected := begin.Add(interval).Add(epsilon)
 
 	// Deadline determines when check for restart should be aborted.
 	deadline := begin.Add(interval).Add(epsilon * count)
@@ -188,24 +187,27 @@ version = 2
 			// temporarily removes the task before restarting.
 			t.Logf("%v: err=%v", now, err)
 		} else {
-			t.Logf("%v: status=%q", now, status)
+			t.Logf("%v: status=%q", now, status.Status)
 
 			if status.Status == Running {
 				break
 			}
 		}
-		if time.Now().After(deadline) {
-			t.Logf("%v: the task was not restarted", now)
+
+		// lastCheck represents the last time the status was seen as not running
+		lastCheck = now
+		if lastCheck.After(deadline) {
+			t.Logf("%v: the task was not restarted", lastCheck)
 			return
 		}
 		time.Sleep(epsilon)
 	}
 
-	now := time.Now()
-	if now.After(expected) {
-		t.Fatalf("%v: the task was restarted, but it must be before %v", now, expected)
+	// Use the last timestamp for when the process was seen as not running for the check
+	if lastCheck.After(expected) {
+		t.Fatalf("%v: the task was restarted, but it must be before %v", lastCheck, expected)
 	}
-	t.Logf("%v: the task was restarted before %v", now, expected)
+	t.Logf("%v: the task was restarted since %v", time.Now(), lastCheck)
 }
 
 // withRestartStatus is a copy of "github.com/containerd/containerd/runtime/restart".WithStatus.