diff --git a/src/utilc.c b/src/utilc.c
index 80851462b..c9e2c7364 100644
--- a/src/utilc.c
+++ b/src/utilc.c
@@ -604,6 +604,12 @@ SEXP _rxode2_powerD(SEXP xS, SEXP lowS, SEXP highS, SEXP lambdaS, SEXP yjS, SEXP
   int inverse = INTEGER(inverseS)[0];
   int yj = INTEGER(yjS)[0];
   double low, high, lambda;
+  if (Rf_length(inverseS) != 1) {
+    Rf_errorcall(R_NilValue, _("'inverse' must be an logical of length 1"));
+  }
+  if (Rf_length(yjS) != 1) {
+    Rf_errorcall(R_NilValue, _("'yj' must be an integer of length 1"));
+  }
   if (Rf_length(lambdaS) != 1){
     Rf_errorcall(R_NilValue, _("'lambda' must be a numeric of length 1"));
   }
diff --git a/tests/testthat/test-logit.R b/tests/testthat/test-logit.R
index 50ed3f0b8..0b3573985 100644
--- a/tests/testthat/test-logit.R
+++ b/tests/testthat/test-logit.R
@@ -51,8 +51,15 @@ rxTest({
 
     expect_equal(logit(1:10, 0L, 11L), logit(as.double(1:10), 0.0, 11.0))
 
-    expect_error(logit(0.5, c(1, 2)))
-    expect_error(logit(0.5, 0, c(1, 2)))
+    expect_equal(logit(7, c(1, 2), c(10, 114)),
+                 c(logit(7, 1, 10),
+                   logit(7, 2, 114)))
+
+    expect_error(.Call(`_rxode2_powerD`, 0.5, c(1, 2), 3, 4, 4L, TRUE))
+    expect_error(.Call(`_rxode2_powerD`, 0.5, 1, c(3, 4), 4, 4L, TRUE))
+    expect_error(.Call(`_rxode2_powerD`, 0.5, 1, 3, 4, c(4L, 5L), TRUE))
+    expect_error(.Call(`_rxode2_powerD`, 0.5, 1, 3, 4, 4L, c(TRUE, FALSE)))
+
     expect_error(logit(0.5, 1, -2))
   })
 
@@ -107,9 +114,5 @@ rxTest({
     )
 
     expect_equal(expit(1:10, 0L, 11L), expit(as.double(1:10), 0.0, 11.0))
-
-    expect_error(expit(0.5, c(1, 2)))
-    expect_error(expit(0.5, 0, c(1, 2)))
-    expect_error(expit(0.5, 1, -2))
   })
 })
diff --git a/tests/testthat/test-rxUiDeparse.R b/tests/testthat/test-rxUiDeparse.R
index cc005bf25..284384511 100644
--- a/tests/testthat/test-rxUiDeparse.R
+++ b/tests/testthat/test-rxUiDeparse.R
@@ -8,6 +8,6 @@ test_that("rxUiDeparse()", {
                                     naInterpolation="nocb", keepInterpolation="nocb", sigmaXform="variance",
                                     omegaXform="variance", returnType="data.frame", sumType="fsum", prodType="logify",
                                     sensType="central"), "a"),
-               str2lang("a <- rxControl(method = \"dop853\", covsInterpolation = \"linear\", returnType = \"data.frame\", sigmaXform = \"variance\", sumType = \"fsum\", prodType = c(\"long double\", \"double\", \"logify\"), sensType = \"central\", naInterpolation = \"nocb\", keepInterpolation = \"nocb\")"))
+               str2lang("a <- rxControl(method = \"dop853\", covsInterpolation = \"linear\", returnType = \"data.frame\", sigmaXform = \"variance\", sumType = \"fsum\", sensType = \"central\", naInterpolation = \"nocb\", keepInterpolation = \"nocb\")"))
 
 })