add unit test for GetServiceTracing

pkg/simple/client/kiali/mock_client.go

@@ -0,0 +1,27 @@
+package kiali
+
+import (
+	"bytes"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+)
+
+type MockClient struct {
+	TokenResult   []byte
+	RequestResult string
+}
+
+func (c *MockClient) Do(req *http.Request) (*http.Response, error) {
+	return &http.Response{
+		StatusCode: 200,
+		Body:       ioutil.NopCloser(bytes.NewReader([]byte(c.RequestResult))),
+	}, nil
+}
+
+func (c *MockClient) PostForm(url string, data url.Values) (resp *http.Response, err error) {
+	return &http.Response{
+		StatusCode: 200,
+		Body:       ioutil.NopCloser(bytes.NewReader(c.TokenResult)),
+	}, nil
+}