diff --git a/test/config_tests.erl b/test/config_tests.erl
index c823d3e..778e383 100644
--- a/test/config_tests.erl
+++ b/test/config_tests.erl
@@ -116,7 +116,7 @@
                 should_return_undefined_atom_on_missed_option(),
                 should_return_custom_default_value_on_missed_option(),
                 should_only_return_default_on_missed_option(),
-                should_fail_to_get_binary_value(),
+                should_fail_to_get_non_string_value(),
                 should_return_any_supported_default()
             ]
         }
@@ -131,7 +131,7 @@
             [
                 should_update_option(),
                 should_create_new_section(),
-                should_fail_to_set_binary_value()
+                should_fail_to_set_non_string_value()
             ]
         }
     }.
@@ -144,7 +144,8 @@
             fun setup/0, fun teardown/1,
             [
                 should_return_undefined_atom_after_option_deletion(),
-                should_be_ok_on_deleting_unknown_options()
+                should_be_ok_on_deleting_unknown_options(),
+                should_fail_to_delete_non_string_value()
             ]
         }
     }.
@@ -243,9 +244,11 @@
     ?_assertEqual("0",
                   config:get("httpd", "port", "bar")).
 
-should_fail_to_get_binary_value() ->
+should_fail_to_get_non_string_value() ->
     ?_assertException(error, badarg,
-                  config:get(<<"foo">>, <<"bar">>, <<"baz">>)).
+                  config:get(<<"foo">>, <<"bar">>, <<"baz">>)),
+    ?_assertException(error, badarg,
+                  config:get([f, o, o], [b, a, r], [b, a, z])).
 
 should_return_any_supported_default() ->
     Values = [undefined, "list", true, false, 0.1, 1],
@@ -269,9 +272,11 @@
             config:get("new_section", "bizzle")
         end).
 
-should_fail_to_set_binary_value() ->
+should_fail_to_set_non_string_value() ->
     ?_assertException(error, badarg,
-        config:set(<<"foo">>, <<"bar">>, <<"baz">>, false)).
+        config:set(<<"foo">>, <<"bar">>, <<"baz">>, false)),
+    ?_assertException(error, badarg,
+        config:set([f, o, o], [b, a, r], [b, a, z], false)).
 
 should_return_undefined_atom_after_option_deletion() ->
     ?_assertEqual(undefined,
@@ -283,6 +288,12 @@
 should_be_ok_on_deleting_unknown_options() ->
     ?_assertEqual(ok, config:delete("zoo", "boo", false)).
 
+should_fail_to_delete_non_string_value() ->
+    ?_assertException(error, badarg,
+        config:delete(<<"foo">>, <<"bar">>, false)),
+    ?_assertException(error, badarg,
+        config:delete([f, o, o], [b, a, r], false)).
+
 should_ensure_in_defaults(_, _) ->
     ?_test(begin
         ?assertEqual("500",