diff --git a/tests/testthat/test-high_level_functions.R b/tests/testthat/test-high_level_functions.R
index e90647a..e1251f6 100644
--- a/tests/testthat/test-high_level_functions.R
+++ b/tests/testthat/test-high_level_functions.R
@@ -15,21 +15,12 @@ fin <- system.file("extdata",
 
 fout1 <- tempfile()
 fout2 <- tempfile()
+fout3 <- tempfile()
 
 test_that("calibrate_carbon returns no error", {
 
   skip_on_cran()
   # these tests could probably be made more useful!!
-  expect_warning(calibrate_carbon(fin, fout1, "ONAQ",
-                                  method = "Bowling_2003",
-                                  calibration_half_width = 0.5,
-                                  force_cal_to_beginning = TRUE,
-                                  force_cal_to_end = TRUE,
-                                  gap_fill_parameters = FALSE,
-                                  filter_ambient = TRUE,
-                                  r2_thres = 0.95,
-                                  correct_ref_data = TRUE,
-                                  write_to_file = TRUE))
   
   expect_no_error(calibrate_carbon(fin, fout1, "ONAQ",
                                   method = "gainoffset",
@@ -64,6 +55,17 @@ test_that("calibrate_carbon returns no error", {
                                    r2_thres = 0.95,
                                    correct_ref_data = TRUE,
                                    write_to_file = FALSE))
+  
+  expect_warning(calibrate_carbon(fin, "/dev/null", "ONAQ",
+                                  method = "Bowling_2003",
+                                  calibration_half_width = 0.5,
+                                  force_cal_to_beginning = TRUE,
+                                  force_cal_to_end = TRUE,
+                                  gap_fill_parameters = FALSE,
+                                  filter_ambient = TRUE,
+                                  r2_thres = 0.95,
+                                  correct_ref_data = TRUE,
+                                  write_to_file = FALSE))
 })