diff --git a/tests/testthat/test-sample_covariates_mvtnorm.R b/tests/testthat/test-sample_covariates_mvtnorm.R
index 60c5ccf..06e39e0 100644
--- a/tests/testthat/test-sample_covariates_mvtnorm.R
+++ b/tests/testthat/test-sample_covariates_mvtnorm.R
@@ -41,33 +41,40 @@ test_that("samples from exponential distribution when exponential = TRUE", {
 })
 
 test_that("conditional argument filters data before sampling", {
-  # TODO: Think of a good way to test this, since the output can include values
-  # outside the conditional range.
-  skip()
   dat <- data.frame(
     AGE = c(20, 30, 40, 50, 60),
     WT  = c(45, 55, 65, 75, 85)
   )
   cndl <- list(WT = c(50, 70))
-  out <- sample_covariates_mvtnorm(
+  n <- 1000
+  out_uncond <- sample_covariates_mvtnorm(
+    data = dat,
+    n_subjects = n
+  )
+  out_cond <- sample_covariates_mvtnorm(
     data = dat,
     conditional = cndl,
-    n_subjects = 50
+    n_subjects = n
   )
-  expect_true(all(out$WT >= 50 & out$WT <= 70))
+  outside_uncond <- sum(out_uncond$WT < 50 | out_uncond$WT > 70)/n
+  outside_cond <- sum(out_cond$WT < 50 | out_cond$WT > 70)/n
+  expect_true(outside_uncond > outside_cond * 3) # uncond should be higher by wide margin
 })
 
 test_that("conditional argument works with multiple variables", {
-  # TODO: Think of a good way to test this, since the output can include values
-  # outside the conditional range.
-  skip()
   dat <- data.frame(
     age = 18:65,
     height = seq(150, 197, length.out = 48),
     weight = rnorm(48)
   )
   cndl <- list(age = c(25, 35), height = c(160, 180))
-  out <- sample_covariates_mvtnorm(dat, n_subjects = 50, conditional = cndl)
-  expect_true(all(out$age >= 25 & out$age <= 35))
-  expect_true(all(out$height >= 160 & out$height <= 180))
+  n <- 1000
+  out_uncond <- sample_covariates_mvtnorm(dat, n_subjects = n)
+  out_cond <- sample_covariates_mvtnorm(dat, n_subjects = n, conditional = cndl)
+  outside_age_uncond <- sum(out_uncond$age < 25 | out_uncond$age > 35)/n
+  outside_age_cond <- sum(out_cond$age < 25 | out_cond$age > 35)/n
+  outside_height_uncond <- sum(out_uncond$height < 160 | out_uncond$height > 180)/n
+  outside_height_cond <- sum(out_cond$height < 160 | out_cond$height > 180)/n
+  expect_true(outside_age_uncond > outside_age_cond * 3)
+  expect_true(outside_height_uncond > outside_height_cond * 3)
 })