From 0e620cf3cab45689f70f22e93f0a482d3efd3f2b Mon Sep 17 00:00:00 2001
From: Jakub Sobon <jakub.sobon@elohim.sk>
Date: Mon, 18 Jun 2018 20:02:17 +0100
Subject: [PATCH] The event queue can now report if it is empty.

---
 eventqueue/eventqueue.go      |  7 +++++++
 eventqueue/eventqueue_test.go | 16 ++++++++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/eventqueue/eventqueue.go b/eventqueue/eventqueue.go
index da7d320..6735255 100644
--- a/eventqueue/eventqueue.go
+++ b/eventqueue/eventqueue.go
@@ -75,6 +75,13 @@ func (u *Unbound) wake() {
 	}
 }
 
+// Empty determines if the queue is empty.
+func (u *Unbound) Empty() bool {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+	return u.empty()
+}
+
 // empty determines if the queue is empty.
 func (u *Unbound) empty() bool {
 	return u.first == nil
diff --git a/eventqueue/eventqueue_test.go b/eventqueue/eventqueue_test.go
index 2b7dc42..53828c4 100644
--- a/eventqueue/eventqueue_test.go
+++ b/eventqueue/eventqueue_test.go
@@ -25,12 +25,14 @@ import (
 
 func TestQueue(t *testing.T) {
 	tests := []struct {
-		desc     string
-		pushes   []terminalapi.Event
-		wantPops []terminalapi.Event
+		desc      string
+		pushes    []terminalapi.Event
+		wantEmpty bool // Checked after pushes and before pops.
+		wantPops  []terminalapi.Event
 	}{
 		{
-			desc: "empty queue returns nil",
+			desc:      "empty queue returns nil",
+			wantEmpty: true,
 			wantPops: []terminalapi.Event{
 				nil,
 			},
@@ -42,6 +44,7 @@ func TestQueue(t *testing.T) {
 				terminalapi.NewError("error2"),
 				terminalapi.NewError("error3"),
 			},
+			wantEmpty: false,
 			wantPops: []terminalapi.Event{
 				terminalapi.NewError("error1"),
 				terminalapi.NewError("error2"),
@@ -59,6 +62,11 @@ func TestQueue(t *testing.T) {
 				q.Push(ev)
 			}
 
+			gotEmpty := q.Empty()
+			if gotEmpty != tc.wantEmpty {
+				t.Errorf("Empty => got %v, want %v", gotEmpty, tc.wantEmpty)
+			}
+
 			for i, want := range tc.wantPops {
 				got := q.Pop()
 				if diff := pretty.Compare(want, got); diff != "" {