[#387] middleware: Extend test coverage

Signed-off-by: Roman Loginov <r.loginov@yadro.com>

api/middleware/response_test.go

@@ -0,0 +1,43 @@
+package middleware
+
+import (
+	"encoding/xml"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type testXMLData struct {
+	XMLName xml.Name `xml:"data"`
+	Text    string   `xml:"text"`
+}
+
+func TestEncodeResponse(t *testing.T) {
+	w := httptest.NewRecorder()
+
+	err := EncodeToResponse(w, []byte{})
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "encode xml response")
+
+	err = EncodeToResponse(w, testXMLData{Text: "test"})
+	require.NoError(t, err)
+
+	expectedXML := "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<data><text>test</text></data>"
+	require.Equal(t, expectedXML, w.Body.String())
+}
+
+func TestErrorResponse(t *testing.T) {
+	errResp := ErrorResponse{Code: "invalid-code"}
+
+	actual := errResp.Error()
+	require.Contains(t, actual, "Error response code")
+
+	errResp.Code = "AccessDenied"
+	actual = errResp.Error()
+	require.Equal(t, "Access Denied.", actual)
+
+	errResp.Message = "Request body is empty."
+	actual = errResp.Error()
+	require.Equal(t, "Request body is empty.", actual)
+}