diff --git a/src/run.rs b/src/run.rs
index 550bac5..99556c6 100644
--- a/src/run.rs
+++ b/src/run.rs
@@ -156,4 +156,26 @@ mod tests {
 		foo.set("bar".into(), Some(42.into()));
 		assert_eq!(loc.eval(&mut scope), Some(42.into()));
 	}
+
+	#[test]
+	fn test_call() {
+		let mut scope = Scope::default();
+		scope.add_fn("sqr", |args| {
+			let [arg] = args.as_slice() else {
+				panic!("exactly one argument expected");
+			};
+			let Some(ValueInner::Number(arg)) = arg else {
+				panic!("number expected");
+			};
+			Some(ValueInner::Number(arg * arg))
+		});
+		assert_eq!(
+			ast::Expression::Call {
+				callee: "sqr".into(),
+				args: vec![ast::Expression::Constant(ast::Constant::Number(7))],
+			}
+			.eval(&mut scope),
+			Some(49.into())
+		);
+	}
 }