diff --git a/g/container/gchan/gchan.go b/g/container/gchan/gchan.go
index 9e762162f..eeba2e153 100644
--- a/g/container/gchan/gchan.go
+++ b/g/container/gchan/gchan.go
@@ -10,55 +10,61 @@
 package gchan
 
 import (
-    "errors"
-    "github.com/gogf/gf/g/container/gtype"
+	"errors"
+
+	"github.com/gogf/gf/g/container/gtype"
 )
 
 // Graceful channel.
 type Chan struct {
-    channel chan interface{}
-    closed  *gtype.Bool
+	channel chan interface{}
+	closed  *gtype.Bool
 }
 
 // New creates a graceful channel with given <limit>.
 func New(limit int) *Chan {
-    return &Chan {
-	    channel : make(chan interface{}, limit),
-        closed  : gtype.NewBool(),
-    }
+	return &Chan{
+		channel: make(chan interface{}, limit),
+		closed:  gtype.NewBool(),
+	}
 }
 
 // Push pushes <value> to channel.
 // It is safe to be called repeatedly.
 func (c *Chan) Push(value interface{}) error {
-    if c.closed.Val() {
-        return errors.New("channel is closed")
-    }
-    c.channel <- value
-    return nil
+	if c.closed.Val() {
+		return errors.New("channel is closed")
+	}
+	c.channel <- value
+	return nil
 }
 
 // Pop pops value from channel.
 // If there's no value in channel, it would block to wait.
 // If the channel is closed, it will return a nil value immediately.
 func (c *Chan) Pop() interface{} {
-    return <- c.channel
+	return <-c.channel
 }
 
 // Close closes the channel.
 // It is safe to be called repeatedly.
 func (c *Chan) Close() {
-    if !c.closed.Set(true) {
-        close(c.channel)
-    }
+	if !c.closed.Set(true) {
+		close(c.channel)
+	}
 }
 
 // See Len.
 func (c *Chan) Size() int {
-    return c.Len()
+	return c.Len()
 }
 
 // Len returns the length of the channel.
 func (c *Chan) Len() int {
 	return len(c.channel)
-}
\ No newline at end of file
+}
+
+// Cap returns the capacity of the channel.
+func (c *Chan) Cap() int {
+	return cap(c.channel)
+}
diff --git a/g/container/gchan/gchan_z_unit_test.go b/g/container/gchan/gchan_z_unit_test.go
new file mode 100644
index 000000000..057113627
--- /dev/null
+++ b/g/container/gchan/gchan_z_unit_test.go
@@ -0,0 +1,47 @@
+package gchan_test
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/gogf/gf/g/container/gchan"
+	"github.com/gogf/gf/g/test/gtest"
+)
+
+func Test_Gchan(t *testing.T) {
+	gtest.Case(t, func() {
+		ch := gchan.New(10)
+
+		gtest.Assert(ch.Cap(), 10)
+		gtest.Assert(ch.Push(1), nil)
+		gtest.Assert(ch.Len(), 1)
+		gtest.Assert(ch.Size(), 1)
+		ch.Pop()
+		gtest.Assert(ch.Len(), 0)
+		gtest.Assert(ch.Size(), 0)
+		ch.Close()
+		gtest.Assert(ch.Push(1), errors.New("channel is closed"))
+
+		ch = gchan.New(0)
+		ch1 := gchan.New(0)
+		go func() {
+			var i = 0
+			for {
+				v := ch.Pop()
+				if v == nil {
+					ch1.Push(i)
+					break
+				}
+				gtest.Assert(v, i)
+				i++
+			}
+		}()
+
+		for index := 0; index < 10; index++ {
+			ch.Push(index)
+		}
+		ch.Close()
+		gtest.Assert(ch1.Pop(), 10)
+		ch1.Close()
+	})
+}