Refactor: make only one API route to update userbooks

internal/testutils/testutils.go

@@ -12,7 +12,6 @@ import (
 	"git.artlef.fr/bibliomane/internal/config"
 	"git.artlef.fr/bibliomane/internal/setup"
 	"github.com/gin-gonic/gin"
-	"github.com/stretchr/testify/assert"
 )
 
 func TestSetup() *gin.Engine {
@@ -62,5 +61,7 @@ func TestBookPutCallWithDemoPayload(t *testing.T, payload string, bookId string,
 	req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", token))
 	w := httptest.NewRecorder()
 	router.ServeHTTP(w, req)
-	assert.Equal(t, expectedCode, w.Code)
+	if w.Code != expectedCode {
+		t.Errorf("%s", w.Body.String())
+	}
 }