test: add empty list test

crates/aiken-lang/src/parser/expr/list.rs

@@ -27,3 +27,16 @@ pub fn parser(
             tail,
         })
 }
+
+#[cfg(test)]
+mod tests {
+
+    use chumsky::Parser;
+
+    use crate::assert_expr;
+
+    #[test]
+    fn empty_list() {
+        assert_expr!("[]");
+    }
+}

crates/aiken-lang/src/parser/expr/snapshots/empty_list.snap

@@ -0,0 +1,9 @@
+---
+source: crates/aiken-lang/src/parser/expr/list.rs
+description: "Code:\n\n[]"
+---
+List {
+    location: 0..2,
+    elements: [],
+    tail: None,
+}

crates/aiken-lang/src/parser/utils.rs

@@ -93,3 +93,26 @@ pub fn type_name_with_args() -> impl Parser<Token, (String, Option<Vec<String>>)
         ),
     )
 }
+
+#[cfg(test)]
+#[macro_use]
+mod macros {
+    #[macro_export]
+    macro_rules! assert_expr {
+        ($code:expr) => {
+            let $crate::parser::lexer::LexInfo { tokens, .. } = $crate::parser::lexer::run($code).unwrap();
+
+            let stream = chumsky::Stream::from_iter($crate::ast::Span::create(tokens.len()), tokens.into_iter());
+
+            let result = $crate::parser::expr::sequence().parse(stream).unwrap();
+
+            insta::with_settings!({
+                description => concat!("Code:\n\n", $code),
+                prepend_module_to_snapshot => false,
+                omit_expression => true
+            }, {
+                insta::assert_debug_snapshot!(result);
+            });
+        };
+    }
+}