refactor: make parser tests integration tests (#485)

let me know if you want this. I think the separation will be beneficial when I add the regression test suite back.

ref: https://doc.rust-lang.org/rust-by-example/testing/integration_testing.html

Author: psteinroe

crates/squawk_parser/src/lexed_str.rs

@@ -86,7 +86,7 @@ impl<'a> LexedStr<'a> {
         let hi = self.start[i + 1] as usize;
         lo..hi
     }
-    pub(crate) fn text_start(&self, i: usize) -> usize {
+    pub fn text_start(&self, i: usize) -> usize {
         assert!(i <= self.len());
         self.start[i] as usize
     }

crates/squawk_parser/src/lib.rs

@@ -60,9 +60,6 @@ mod event;
 mod input;
 mod output;
 
-#[cfg(test)]
-mod test;
-
 pub use crate::{
     lexed_str::LexedStr,
     // output::{Output, Step},