diff --git a/tests/testthat/test_warnings_and_errors.R b/tests/testthat/test_warnings_and_errors.R
index f103997..fe4a57b 100644
--- a/tests/testthat/test_warnings_and_errors.R
+++ b/tests/testthat/test_warnings_and_errors.R
@@ -4,7 +4,7 @@ source("test_objects.R")
 
 testthat::test_that("new_observation as list", {
   testthat::expect_warning(
-    modelStudio::modelStudio(explain_glm,
+    ms <- modelStudio::modelStudio(explain_glm,
                              new_observation = as.list(titanic_test[1,-9]),
                              show_info = v, B = 3)
   )
@@ -12,7 +12,7 @@ testthat::test_that("new_observation as list", {
 
 testthat::test_that("check_single_prediction error", {
   testthat::expect_error(
-    modelStudio::modelStudio(explainer_xgb,
+    ms <- modelStudio::modelStudio(explainer_xgb,
                              new_observation = model_matrix_train[1,],
                              show_info = v, B = 3)
   )
@@ -20,7 +20,7 @@ testthat::test_that("check_single_prediction error", {
 
 testthat::test_that("deprecated modelStudioOptions", {
   testthat::expect_warning(
-    modelStudio::modelStudioOptions()
+    ms <- modelStudio::modelStudioOptions()
   )
 })
 
@@ -32,7 +32,7 @@ new_ms <- modelStudio::ms_update_observations(ms, explain_rf, B = 2, show_info =
 testthat::test_that("duplicated ids", {
   testthat::expect_is(new_ms, "modelStudio")
   testthat::expect_warning(
-    modelStudio::ms_update_observations(ms, explain_rf, B = 2, show_info = v,
+    ms <- modelStudio::ms_update_observations(ms, explain_rf, B = 2, show_info = v,
                                        new_observation = apartments[1,],
                                        new_observation_y = apartments$m2.price[1])
   )