Fix Jaro and Jaro-Winkler when the length is one

CHANGELOG.md

@@ -1,8 +1,15 @@
 # Change Log
+
 This project attempts to adhere to [Semantic Versioning](http://semver.org).
 
 ## [Unreleased]
 
+### Fixed
+
+- Fix Jaro and Jaro-Winkler when the arguments have lengths of 1 and are equal.
+  Previously, the functions would erroneously return 0 instead of 1. Thanks to
+  [@vvrably](https://github.com/vvrably) for pointing out the issue.
+
 ## [0.9.2] - (2019-05-09)
 
 ### Changed
@@ -25,14 +32,19 @@ This project attempts to adhere to [Semantic Versioning](http://semver.org).
 - Generic distance functions (thanks [@lovasoa](https://github.com/lovasoa))
 
 ## [0.8.0] - (2018-08-19)
+
 ### Added
+
 - Normalized versions of Levenshtein and Damerau-Levenshtein (thanks [@gentoid](https://github.com/gentoid))
 
 ## [0.7.0] - (2018-01-17)
+
 ### Changed
+
 - Faster Levenshtein implementation (thanks [@wdv4758h](https://github.com/wdv4758h))
 
 ### Removed
+
 - Remove the "against_vec" functions. They are one-liners now, so they don't
   seem to add enough value to justify making the API larger. I didn't find
   anybody using them when I skimmed through a GitHub search. If you do use them,
@@ -42,83 +54,117 @@ let distances = strings.iter().map(|a| jaro(target, a)).collect();
 ```
 
 ## [0.6.0] - (2016-12-26)
+
 ### Added
+
 - Add optimal string alignment distance
 
 ### Fixed
+
 - Fix Damerau-Levenshtein implementation (previous implementation was actually
   optimal string alignment; see this [Damerau-Levenshtein explanation])
 
 ## [0.5.2] - (2016-11-21)
+
 ### Changed
+
 - Remove Cargo generated documentation in favor of a [docs.rs] link
 
 ## [0.5.1] - (2016-08-23)
+
 ### Added
+
 - Add Cargo generated documentation
 
 ### Fixed
+
 - Fix panic when Jaro or Jaro-Winkler are given strings both with a length of
   one
 
 ## [0.5.0] - (2016-08-11)
+
 ### Changed
+
 - Make Hamming faster (thanks @IBUzPE9) when the two strings have the same
   length but slower when they have different lengths
 
 ## [0.4.1] - (2016-04-18)
+
 ### Added
+
 - Add Vagrant setup for development
 - Add AppVeyor configuration for Windows CI
 
 ### Fixed
+
 - Fix metrics when given strings with multibyte characters (thanks @WanzenBug)
 
 ## [0.4.0] - (2015-06-10)
+
 ### Added
+
 - For each metric, add a function that takes a vector of strings and returns a
 vector of results (thanks @ovarene)
 
 ## [0.3.0] - (2015-04-30)
+
 ### Changed
+
 - Remove usage of unstable Rust features
 
 ## [0.2.5] - (2015-04-24)
+
 ### Fixed
+
 - Remove unnecessary `Float` import from doc tests
 
 ## [0.2.4] - (2015-04-15)
+
 ### Fixed
+
 - Remove unused `core` feature flag
 
 ## [0.2.3] - (2015-04-01)
+
 ### Fixed
+
 - Remove now unnecessary `Float` import
 
 ## [0.2.2] - (2015-03-29)
+
 ### Fixed
+
 - Remove usage of `char_at` (marked as unstable)
 
 ## [0.2.1] - (2015-02-20)
+
 ### Fixed
+
 - Update bit vector import to match Rust update
 
 ## [0.2.0] - (2015-02-19)
+
 ### Added
+
 - Implement Damerau-Levenshtein
 - Add tests in docs
 
 ## [0.1.1] - (2015-02-10)
+
 ### Added
+
 - Configure Travis for CI
 - Add rustdoc comments
 
 ### Fixed
+
 - Limit Jaro-Winkler return value to a maximum of 1.0
 - Fix float comparisons in tests
 
 ## [0.1.0] - (2015-02-09)
+
 ### Added
+
 - Implement Hamming, Jaro, Jaro-Winkler, and Levenshtein
 
 [Unreleased]: https://github.com/dguo/strsim-rs/compare/0.9.2...HEAD

src/lib.rs

@@ -72,9 +72,11 @@ pub fn generic_jaro<'a, 'b, Iter1, Iter2, Elem1, Elem2>(a: &'a Iter1, b: &'b Ite
     // The check for lengths of one here is to prevent integer overflow when
     // calculating the search range.
     if a_len == 0 && b_len == 0 {
-        return 1.0
-    } else if a_len == 0 || b_len == 0 || (a_len == 1 && b_len == 1) {
+        return 1.0;
+    } else if a_len == 0 || b_len == 0 {
         return 0.0;
+    } else if a_len == 1 && b_len == 1 {
+        return if a.into_iter().eq(b.into_iter()) { 1.0} else { 0.0 };
     }
 
     let search_range = (max(a_len, b_len) / 2) - 1;
@@ -491,6 +493,11 @@ mod tests {
         assert_eq!(0.0, jaro("a", "b"));
     }
 
+    #[test]
+    fn jaro_same_one_character() {
+        assert_eq!(1.0, jaro("a", "a"));
+    }
+
     #[test]
     fn generic_jaro_diff() {
         assert_eq!(0.0, generic_jaro(&[1, 2], &[3, 4]));
@@ -561,6 +568,11 @@ mod tests {
         assert_eq!(0.0, jaro_winkler("a", "b"));
     }
 
+    #[test]
+    fn jaro_winkler_same_one_character() {
+        assert_eq!(1.0, jaro_winkler("a", "a"));
+    }
+
     #[test]
     fn jaro_winkler_diff_no_transposition() {
         assert!((0.840 - jaro_winkler("dwayne", "duane")).abs() < 0.001);