Fix agree validation to only accept "yes" or "no"

Although the documentation for agree states that it only accepts
yes/no/y/n case-insensitively, the Regexp allowed any string which
started with /y/i or ended with /no?/i and interpreted any starting with
'y' as true.  Fix the Regexp to properly exclude the start/end markers
from the alternation and add a test value to confirm it works.

Signed-off-by: Kevin Locke <kevin@kevinlocke.name>

2 files changed, 2 insertions, 2 deletions

diff --git a/lib/highline.rb b/lib/highline.rb
index ba409b6..ff6da99 100755
--- a/lib/highline.rb
+++ b/lib/highline.rb
@@ -190,7 +190,7 @@ class HighLine
   # @see Question#character
   def agree( yes_or_no_question, character = nil )
     ask(yes_or_no_question, lambda { |yn| yn.downcase[0] == ?y}) do |q|
-      q.validate                 = /\Ay(?:es)?|no?\Z/i
+      q.validate                 = /\A(?:y(?:es)?|no?)\Z/i
       q.responses[:not_valid]    = 'Please enter "yes" or "no".'
       q.responses[:ask_on_error] = :question
       q.character                = character
diff --git a/test/test_highline.rb b/test/test_highline.rb
index a5101c1..7c95557 100755
--- a/test/test_highline.rb
+++ b/test/test_highline.rb
@@ -35,7 +35,7 @@ class TestHighLine < Minitest::Test
   end
   
   def test_agree
-    @input << "y\nyes\nYES\nHell no!\nNo\n"
+    @input << "y\nyes\nYES\nyuk\nHell no!\nNo\n"
     @input.rewind
 
     assert_equal(true, @terminal.agree("Yes or no?  "))