Handle nil component in RenderGomponent: return NoContent response if…

… component is nil; add corresponding unit test

internal/util/echoutil/render_gomponent.go

@@ -15,6 +15,10 @@ type renderer interface {
 // RenderGomponent renders a gomponents component to the response of
 // the echo context.
 func RenderGomponent(c echo.Context, code int, component renderer) error {
+	if component == nil {
+		return c.NoContent(code)
+	}
+
 	buf := bytes.Buffer{}
 	err := component.Render(&buf)
 	if err != nil {

internal/util/echoutil/render_gomponent_test.go

@@ -53,3 +53,15 @@ func TestRenderGomponent(t *testing.T) {
 		assert.Equal(t, "render nok", rec.Body.String())
 	})
 }
+
+func TestRenderNilGomponent(t *testing.T) {
+	e := echo.New()
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+	c := e.NewContext(req, rec)
+
+	err := RenderGomponent(c, http.StatusOK, nil)
+	assert.NoError(t, err)
+	assert.Equal(t, http.StatusOK, rec.Code)
+	assert.Equal(t, "", rec.Body.String())
+}