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src/tests.rs

@@ -52,3 +52,40 @@ fn test_branch_sum() {
     let results = formula.run(vec![0f64, 1f64, 2f64, 3f64, 4f64, 5f64]);
     assert_eq!(results, vec![1f64, 2f64, 3f64, 4f64, 5f64, 6f64])
 }
+
+#[test]
+fn test_display_as_text() {
+    let mut formula = Formula::new();
+    assert!(
+        formula
+            .modify_tree()
+            .insert_node(
+                Node::function("sum".to_string(), |inputs| inputs.iter().sum(), None),
+                None
+            )
+            .is_err()
+            == false
+    );
+    assert!(
+        formula
+            .modify_tree()
+            .go_down(0)
+            .add_node(Node::function(
+                "sin".to_string(),
+                |inputs| inputs[0].sin(),
+                Some(1)
+            ))
+            .is_err()
+            == false
+    );
+    assert!(
+        formula
+            .modify_tree()
+            .go_down(0)
+            .go_down(1)
+            .add_node(Node::variable())
+            .is_err()
+            == false
+    );
+    assert_eq!(formula.as_text(), "sum(X,sin(X))".to_string());
+}