Adds new tests and increases code coverage.

cmd/kube-proxy/app/server_test.go

@@ -19,6 +19,7 @@ package app
 import (
 	"testing"
 
+	"github.com/stretchr/testify/assert"
 	"k8s.io/kubernetes/pkg/api"
 )
 
@@ -59,3 +60,24 @@ func Test_mayTryIptablesProxy(t *testing.T) {
 		}
 	}
 }
+
+//This test verifies that Proxy Server does not crash that means
+//Config and iptinterface are not nil when CleanupAndExit is true.
+//To avoid proxy crash: https://github.com/kubernetes/kubernetes/pull/14736
+func TestProxyServerWithCleanupAndExit(t *testing.T) {
+
+	//creates default config
+	config := NewProxyConfig()
+
+	//sets CleanupAndExit manually
+	config.CleanupAndExit = true
+
+	//creates new proxy server
+	proxyserver, err := NewProxyServerDefault(config)
+
+	//verifies that nothing is nill except error
+	assert.Nil(t, err)
+	assert.NotNil(t, proxyserver)
+	assert.NotNil(t, proxyserver.Config)
+	assert.NotNil(t, proxyserver.IptInterface)
+}