feat(ast): Add graph output

src/frontend/parser.rs

@@ -654,6 +654,7 @@ mod tests {
     use std::io::BufRead;
     use std::path::Path;
     use std::fs::File;
+    use crate::ast::graph::AstGraphExt;
     use crate::frontend::lexer::Lexer;
     use crate::utils::case_list::CaseList;
     use crate::utils::num_sequence::NumberSequence;
@@ -686,7 +687,10 @@ mod tests {
                 is_error = true;
             }
             let mut parser = Parser::new(tokens, diagnostics);
-            let _compile_unit = parser.parse_compile_unit();
+            let compile_unit = parser.parse_compile_unit();
+            let dot = compile_unit.to_dot();
+            let case_name = case_list.get_case_name(case_no).unwrap().strip_suffix(".c").unwrap();
+            std::fs::write(format!("output/{}.dot", case_name), dot).unwrap();
             if !parser.diagnostics.is_empty() {
                 parser.diagnostics.print(&format!("{}", case_path.display()), &full_text);
                 is_error = true;