diff --git a/tests/testthat/test_sfcb.R b/tests/testthat/test_sfcb.R
index faf89f15e3745f8140e4b13b59b8c6bfcc10c61d..f0868ca703251b7fd55b62b92e007a412bf71d68 100644
--- a/tests/testthat/test_sfcb.R
+++ b/tests/testthat/test_sfcb.R
@@ -91,3 +91,31 @@ test_that("`sfcb` works for one `at` with selection.", {
                 range.at = c(5, 12))
   expect_named(out14, expected_outputs)
 })
+
+test_that("`sfcb` properly returns error when expected.", {
+  expect_error({sfcb(rainfall, truffles, at = "1")},
+               "'at' must be a positive integer", fixed = FALSE)
+  expect_error({sfcb(rainfall, truffles, at = -3)},
+               "'at' must be a positive integer", fixed = FALSE)
+  expect_error({sfcb(rainfall, truffles, at = 2.4)},
+               "'at' must be a positive integer", fixed = FALSE)
+  
+  expect_error({sfcb(rainfall, truffles, range.at = 1:3)},
+               "'range.at' must be a vector of minimum and maximum numbers", 
+               fixed = FALSE)
+  expect_error({sfcb(rainfall, truffles, range.at = c("1", "2"))},
+               "'range.at' must be a vector of minimum and maximum numbers", 
+               fixed = FALSE)
+  expect_error({sfcb(rainfall, truffles, range.at = c(-1, 2))},
+               "'range.at' must be a vector of minimum and maximum numbers", 
+               fixed = FALSE)
+  expect_error({sfcb(rainfall, truffles, range.at = c(1.4, 2))},
+               "'range.at' must be a vector of minimum and maximum numbers", 
+               fixed = FALSE)
+  expect_error({sfcb(rainfall, truffles, range.at = c(5, 2))},
+               "'range.at' must be a vector of minimum and maximum numbers", 
+               fixed = FALSE)
+  
+  expect_error({sfcb(rainfall, truffles, seed = "1")}, 
+               "'seed' must be numeric!", fixed = FALSE)
+})