diff --git a/R/cod_structure_input.R b/R/cod_structure_input.R
index 6bb6999..792897e 100644
--- a/R/cod_structure_input.R
+++ b/R/cod_structure_input.R
@@ -19,7 +19,7 @@
 #'   record identifiers. Default to NULL. If NULL, unique record identifiers
 #'   will be generated.
 #'
-#' @returns A data.frame with 6 columns and number of rows equal to `df` with
+#' @returns A tibble with 6 columns and number of rows equal to `df` with
 #'   names `"FreeId"`, `"Sex"`, `"Age Value"`, `"Age Type"`, `"Code"`, and
 #'   `"Death Date"`.
 #'
diff --git a/man/cod_structure.Rd b/man/cod_structure.Rd
index 6aa93a2..2dd17f3 100644
--- a/man/cod_structure.Rd
+++ b/man/cod_structure.Rd
@@ -32,7 +32,7 @@ record identifiers. Default to NULL. If NULL, unique record identifiers
 will be generated.}
 }
 \value{
-A data.frame with 6 columns and number of rows equal to \code{df} with
+A tibble with 6 columns and number of rows equal to \code{df} with
 names \code{"FreeId"}, \code{"Sex"}, \code{"Age Value"}, \code{"Age Type"}, \code{"Code"}, and
 \code{"Death Date"}.
 }
diff --git a/tests/testthat/test-cod_check_input.R b/tests/testthat/test-cod_check_input.R
index 1a3c39e..ef37f92 100644
--- a/tests/testthat/test-cod_check_input.R
+++ b/tests/testthat/test-cod_check_input.R
@@ -11,4 +11,8 @@ testthat::test_that(
         "code_check", "code_check_note",
         "dod_check", "dod_check_note")
     )
+
+    expect_warning(
+      cod_check_codedit_input(icd10_example |> dplyr::select(-FreeId))
+    )
 })
diff --git a/tests/testthat/test-cod_structure_input.R b/tests/testthat/test-cod_structure_input.R
new file mode 100644
index 0000000..765c5cf
--- /dev/null
+++ b/tests/testthat/test-cod_structure_input.R
@@ -0,0 +1,19 @@
+# Tests for cod_structure_input ------------------------------------------------
+
+df <- data.frame(
+  id = 1:3,
+  sex = c(1, 1, 2),
+  dob = c("1977-11-05", "1971-04-04", "2012-08-13"),
+  dod = c("2024-06-28", "2023-10-11", "2023-09-25"),
+  code = c("P219", "O230", "Q913")
+)
+
+
+testthat::test_that(
+  "cod_structure_input outputs appropriate results",
+
+  expect_s3_class(
+    cod_structure_input(df, sex = "sex", dob = "dob", dod = "dod", code = "code"),
+    "tbl"
+  )
+)