diff --git a/client/pluginManager_test.go b/client/pluginManager_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..a7da6ea2af4a8e7e1192115caf46020ddb9087fe
--- /dev/null
+++ b/client/pluginManager_test.go
@@ -0,0 +1,37 @@
+package client
+
+import (
+	"github.com/golang/mock/gomock"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("PluginManager test", func() {
+	var (
+		ctrl *gomock.Controller
+	)
+
+	BeforeEach(func() {
+		ctrl = gomock.NewController(GinkgoT())
+	})
+
+	AfterEach(func() {
+		ctrl.Finish()
+	})
+
+	Context("basic function test", func() {
+		It("get install plugin query string", func() {
+			names := make([]string, 0)
+			Expect(getPluginsInstallQuery(names)).To(Equal(""))
+
+			names = append(names, "abc")
+			Expect(getPluginsInstallQuery(names)).To(Equal("plugin.abc="))
+
+			names = append(names, "def")
+			Expect(getPluginsInstallQuery(names)).To(Equal("plugin.abc=&plugin.def="))
+
+			names = append(names, "")
+			Expect(getPluginsInstallQuery(names)).To(Equal("plugin.abc=&plugin.def="))
+		})
+	})
+})
diff --git a/client/pluginManger.go b/client/pluginManger.go
index 469b5c081da160653a1e00d2b6611e1ed13dfbaf..95e086acae3ab70161367e6237e4e9766d8d8dce 100644
--- a/client/pluginManger.go
+++ b/client/pluginManger.go
@@ -153,12 +153,20 @@ func (p *PluginManager) GetPlugins() (pluginList *InstalledPluginList, err error
 	return
 }
 
+func getPluginsInstallQuery(names []string) string {
+	pluginNames := make([]string, 0)
+	for _, name := range names {
+		if name == "" {
+			continue
+		}
+		pluginNames = append(pluginNames, fmt.Sprintf("plugin.%s=", name))
+	}
+	return strings.Join(pluginNames, "&")
+}
+
 // InstallPlugin install a plugin by name
 func (p *PluginManager) InstallPlugin(names []string) (err error) {
-	for i, name := range names {
-		names[i] = fmt.Sprintf("plugin.%s", name)
-	}
-	api := fmt.Sprintf("%s/pluginManager/install?%s", p.URL, strings.Join(names, "=&"))
+	api := fmt.Sprintf("%s/pluginManager/install?%s", p.URL, getPluginsInstallQuery(names))
 	var (
 		req      *http.Request
 		response *http.Response
@@ -180,8 +188,22 @@ func (p *PluginManager) InstallPlugin(names []string) (err error) {
 		data, err = ioutil.ReadAll(response.Body)
 		if code == 200 {
 			fmt.Println("install succeed.")
+		} else if code == 400 {
+			if errMsg, ok := response.Header["X-Error"]; ok {
+				for _, msg := range errMsg {
+					fmt.Println(msg)
+				}
+			} else {
+				fmt.Println("Cannot found plugins", names)
+			}
 		} else {
-			log.Fatal(string(data))
+			fmt.Println(response.Header)
+			fmt.Println("status code", code)
+			if err == nil && p.Debug && len(data) > 0 {
+				ioutil.WriteFile("debug.html", data, 0664)
+			} else if err != nil {
+				log.Fatal(err)
+			}
 		}
 	} else {
 		log.Fatal(err)
diff --git a/client/setup_test.go b/client/setup_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..0c65a85e8ff1b5d21ba4008a154618e41577b43a
--- /dev/null
+++ b/client/setup_test.go
@@ -0,0 +1,13 @@
+package client
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestJenkinsClient(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "jenkins client test")
+}