add -p argument to debug single paragraph, fix issues, sorry for the large commit...

src/paragraph/mod.rs

@@ -122,11 +122,16 @@ mod tests {
 
             let actual = &builder.history;
 
-            let expected = fs::read_to_string(&expected_path)
-                .unwrap_or_else(|_| panic!("Could not read file {expected_path}."));
-            let expected = expected.trim().split('\n').collect::<Vec<&str>>();
-
-            assert_eq!(actual, &expected);
+            match fs::read_to_string(&expected_path) {
+                Ok(expected) => {
+                    let e = expected.trim().split('\n').collect::<Vec<&str>>();
+                    assert_eq!(actual, &e);
+                }
+                Err(_) => {
+                    let to_write = actual.join("\n");
+                    fs::write(expected_path, to_write).expect("Unable to write file");
+                }
+            }
         }
     }
 }