ivy-test.el (counsel-find-file-single-match-directories): Add test

Fixes #2596

ivy-test.el

@@ -1526,10 +1526,22 @@ a buffer visiting a file."
                         :dir "tests/find-file/directories-with-spaces/"))
              "tests/find-file/directories-with-spaces/bar baz ii/file2"))))
 
+(ert-deftest counsel-find-file-single-match-directories ()
+  (should (string= (let ((ivy-extra-directories nil))
+                     (file-relative-name
+                      (ivy-with '(counsel-find-file) "a TAB TAB TAB"
+                                :dir "tests/find-file/single-match-directories/")))
+                   "tests/find-file/single-match-directories/a/file_in_a.txt"))
+  (should (string= (let ((ivy-extra-directories nil))
+                     (file-relative-name
+                      (ivy-with '(counsel-find-file) "b TAB TAB TAB"
+                                :dir "tests/find-file/single-match-directories/")))
+                   "tests/find-file/single-match-directories/ba/file_in_ba.txt")))
+
 (ert-deftest counsel--split-string-with-eol-cr ()
   (should
-     (equal (counsel--split-string "one\rtwo")
-            '("one" "two"))))
+   (equal (counsel--split-string "one\rtwo")
+          '("one" "two"))))
 
 (ert-deftest counsel--split-string-with-eol-lf ()
   (should

ivy.el

@@ -1095,7 +1095,9 @@ If the text hasn't changed as a result, forward to `ivy-alt-done'."
   (when (and
          (eq (ivy-state-collection ivy-last) #'read-file-name-internal)
          (= 1 (length
-               (ivy--re-filter ivy-regex ivy--all-candidates)))
+               (ivy--re-filter
+                (concat "^" (string-remove-prefix "^" ivy-regex))
+                ivy--all-candidates)))
          (let ((default-directory ivy--directory))
            (file-directory-p (ivy-state-current ivy-last))))
     (ivy--directory-done)))