Fix `cd`ing home when no matching directory in `fish`

Prior to this change, executing `z sjlk` (assuming no `sjlk` directory
in your database) would result in going back to the user's home.

CHANGELOG.md

@@ -18,6 +18,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Interactive mode in `zoxide` no longer throws an error if `fzf` exits gracefully.
 - Canonicalize to regular paths instead of UNC paths on Windows.
 
+### Fixed
+
+- When no match is found, `fish` stays in the current directory.
+
 ## [0.3.1] - 2020-04-03
 
 ### Added

src/subcommand/init.rs

@@ -160,15 +160,11 @@ function {}
         or return $status
 
     else
-        # FIXME: use string-collect from fish 3.1.0 once it has wider adoption
-        set -l IFS ''
         set -l result (zoxide query $argv)
 
-        if test -d $result
+        if begin; test -d $result; and string length -q -- $result; end
             _z_cd $result
             or return $status
-        else if test -n "$result"
-            echo $result
         end
     end
 end