Ensure maxSize > 0

pool.go

@@ -94,8 +94,12 @@ type Pool struct {
 	closed bool
 }
 
-// NewPool creates a new pool.
+// NewPool creates a new pool. Panics if maxSize is less than 1.
 func NewPool(constructor Constructor, destructor Destructor, maxSize int32) *Pool {
+	if maxSize < 1 {
+		panic("maxSize is less than 1")
+	}
+
 	return &Pool{
 		cond:        sync.NewCond(new(sync.Mutex)),
 		destructWG:  &sync.WaitGroup{},

pool_test.go

@@ -72,6 +72,12 @@ func waitForRead(ch chan int) bool {
 	}
 }
 
+func TestNewPoolRequiresMaxSizeGreaterThan0(t *testing.T) {
+	constructor, _ := createConstructor()
+	assert.Panics(t, func() { puddle.NewPool(constructor, stubDestructor, -1) })
+	assert.Panics(t, func() { puddle.NewPool(constructor, stubDestructor, 0) })
+}
+
 func TestPoolAcquireCreatesResourceWhenNoneIdle(t *testing.T) {
 	constructor, _ := createConstructor()
 	pool := puddle.NewPool(constructor, stubDestructor, 10)