Fixes #6

Pretty ugly workaround, there's likely a safer alternative.

src/lib.rs

@@ -1218,6 +1218,21 @@ impl Parser {
         let len_l = tokens.len();
         let mut hms_idx = None;
 
+        // There's a super weird edge case that can happen
+        // because Python safely handles negative array indices,
+        // and Rust (because of usize) does not.
+        let idx_minus_two = if idx == 1 && len_l > 0 {
+            len_l - 1
+        } else if idx == 0 && len_l > 1 {
+            len_l - 2
+        } else if idx > 1 {
+            idx - 2
+        } else if len_l == 0{
+            panic!("Attempting to find_hms_index() wih no tokens.");
+        } else {
+            0
+        };
+
         if idx + 1 < len_l && info.get_hms(&tokens[idx + 1]).is_some() {
             hms_idx = Some(idx + 1)
         } else if allow_jump && idx + 2 < len_l && tokens[idx + 1] == " "
@@ -1227,7 +1242,7 @@ impl Parser {
         } else if idx > 0 && info.get_hms(&tokens[idx - 1]).is_some() {
             hms_idx = Some(idx - 1)
         } else if len_l > 0 && idx > 0 && idx == len_l - 1 && tokens[idx - 1] == " "
-            && info.get_hms(&tokens[idx - 2]).is_some()
+            && info.get_hms(&tokens[idx_minus_two]).is_some()
         {
             hms_idx = Some(idx - 2)
         }

src/tests.rs

@@ -1,8 +1,17 @@
-use ParseError;
+use chrono::NaiveDate;
+use std::collections::HashMap;
+
 use parse;
+use ParseError;
+use Parser;
 
 #[test]
 fn test_fuzz() {
 
     assert_eq!(parse("\x2D\x38\x31\x39\x34\x38\x34"), Err(ParseError::InvalidMonth));
+
+    let default = NaiveDate::from_ymd(2016, 6, 29).and_hms(0, 0, 0);
+    let mut p = Parser::default();
+    let res = p.parse("\x0D\x31", None, None, false, false, Some(&default), false, HashMap::new()).unwrap();
+    assert_eq!(res.0, default);
 }