Fix TestError: Wait for process to terminate (#3201)

Co-authored-by: Madush Soysa <[email protected]>
Co-authored-by: Pavan Navarathna <[email protected]>

pkg/kanx/kanx_test.go

@@ -194,9 +194,12 @@ func (s *KanXSuite) TestError(c *C) {
 	err = sp.cmd.Process.Kill()
 	c.Assert(err, IsNil)
 
-	ps, err = ListProcesses(ctx, addr)
-	c.Assert(err, IsNil)
-	c.Assert(ps, HasLen, 1)
+	_ = poll.Wait(ctx, func(context.Context) (bool, error) {
+		ps, err = ListProcesses(ctx, addr)
+		c.Assert(err, IsNil)
+		c.Assert(ps, HasLen, 1)
+		return ps[0].GetState() != ProcessState_PROCESS_STATE_RUNNING, nil
+	})
 	c.Assert(ps[0].GetPid(), Equals, p.GetPid())
 	c.Assert(ps[0].GetState(), Equals, ProcessState_PROCESS_STATE_FAILED)
 	c.Assert(ps[0].GetExitErr(), Equals, "signal: killed")