From 1cd19c2f469a0b8d76879ecb4e7cf3e1aac86393 Mon Sep 17 00:00:00 2001
From: Yota Toyama <raviqqe@gmail.com>
Date: Sat, 18 Nov 2017 18:41:59 +0900
Subject: [PATCH] Create semaphore object

---
 semaphore.go      | 17 +++++++++++++++++
 semaphore_test.go | 28 ++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 semaphore.go
 create mode 100644 semaphore_test.go

diff --git a/semaphore.go b/semaphore.go
new file mode 100644
index 0000000..ae8383d
--- /dev/null
+++ b/semaphore.go
@@ -0,0 +1,17 @@
+package main
+
+type semaphore struct {
+	channel chan bool
+}
+
+func newSemaphore(n int) semaphore {
+	return semaphore{make(chan bool, n)}
+}
+
+func (s semaphore) Request() {
+	s.channel <- true
+}
+
+func (s semaphore) Release() {
+	<-s.channel
+}
diff --git a/semaphore_test.go b/semaphore_test.go
new file mode 100644
index 0000000..c5a199e
--- /dev/null
+++ b/semaphore_test.go
@@ -0,0 +1,28 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewSemaphore(t *testing.T) {
+	newSemaphore(1)
+}
+
+func TestSemaphoreRequest(t *testing.T) {
+	s := newSemaphore(1)
+
+	s.Request()
+
+	assert.Equal(t, 1, len(s.channel))
+}
+
+func TestSemaphoreRelease(t *testing.T) {
+	s := newSemaphore(1)
+
+	s.Request()
+	s.Release()
+
+	assert.Equal(t, 0, len(s.channel))
+}