diff --git a/tests/test_discord_helpers.c b/tests/test_discord_helpers.c
index 954bfdb..4b54d0e 100644
--- a/tests/test_discord_helpers.c
+++ b/tests/test_discord_helpers.c
@@ -99,6 +99,30 @@ static int test_route_message_create_fixture(void)
 	return 0;
 }
 
+static int test_route_message_create_rejects_edge_cases(void)
+{
+	const char *allowed[] = { "user-42" };
+	const char *bot_author = "{\"author\":{\"id\":\"user-42\",\"bot\":true},\"channel_id\":\"chan-1\"}";
+	const char *empty_author_id = "{\"author\":{\"id\":\"\",\"bot\":false},\"channel_id\":\"chan-1\"}";
+	const char *guild_empty_bot = "{\"author\":{\"id\":\"user-42\",\"bot\":false},"
+	                              "\"guild_id\":\"g1\",\"channel_id\":\"chan-2\","
+	                              "\"mentions\":[{\"id\":\"bot-9\"}]}";
+	cJSON *bot = cJSON_Parse(bot_author);
+	cJSON *empty_id = cJSON_Parse(empty_author_id);
+	cJSON *guild = cJSON_Parse(guild_empty_bot);
+	char sess[128];
+	ASSERT(bot && empty_id && guild);
+	ASSERT(discord_helpers_route_message_create(NULL, allowed, 1, "bot-9", sess, sizeof(sess)) == -1);
+	ASSERT(discord_helpers_route_message_create(bot, allowed, 1, "bot-9", sess, sizeof(sess)) == 0);
+	ASSERT(discord_helpers_route_message_create(empty_id, allowed, 1, "bot-9", sess, sizeof(sess)) == 0);
+	ASSERT(discord_helpers_route_message_create(guild, allowed, 1, "", sess, sizeof(sess)) == 0);
+	ASSERT(discord_helpers_route_message_create(guild, allowed, 1, NULL, sess, sizeof(sess)) == 0);
+	cJSON_Delete(bot);
+	cJSON_Delete(empty_id);
+	cJSON_Delete(guild);
+	return 0;
+}
+
 int main(void)
 {
 	RUN(test_allow_entry_equals());
@@ -108,6 +132,7 @@ int main(void)
 	RUN(test_backoff_math());
 	RUN(test_lifecycle_str());
 	RUN(test_route_message_create_fixture());
+	RUN(test_route_message_create_rejects_edge_cases());
 	printf("test_discord_helpers: all tests passed\n");
 	return 0;
 }