test

src/test/mod.rs

@@ -3,10 +3,24 @@ mod sexp;
 use super::*;
 
 #[test]
-fn parsing() {
+fn basic_parsing() {
     let (parsed, rest) = literal("a").parse("a yolo").unwrap();
     assert_eq!(parsed, "a");
     assert_eq!(rest, " yolo");
+
+    fn bare_function_parser(input: &str) -> ParseResult<&str, i32, String> {
+        match input.chars().next() {
+            Some('0') => Ok((0, &input[1..])),
+            Some('1') => Ok((1, &input[1..])),
+            _ => Err(("lol a parse error".to_string(), input)),
+        }
+    }
+
+    assert_eq!(bare_function_parser.parse("0foo"), Ok((0, "foo")));
+    assert_eq!(
+        bare_function_parser.parse("xfoo"),
+        Err(("lol a parse error".to_string(), "xfoo"))
+    );
 }
 
 #[test]