UPDATE: Dump of initial files

base/src/test/test_fn_sum.rs

@@ -0,0 +1,19 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::test::util::new_empty_model;
+
+#[test]
+fn test_fn_sum_arguments() {
+    let mut model = new_empty_model();
+    model._set("A1", "=SUM()");
+    model._set("A2", "=SUM(1, 2, 3)");
+    model._set("A3", "=SUM(1, )");
+    model._set("A4", "=SUM(1,   , 3)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"#ERROR!");
+    assert_eq!(model._get_text("A2"), *"6");
+    assert_eq!(model._get_text("A3"), *"1");
+    assert_eq!(model._get_text("A4"), *"4");
+}