diff --git a/README.md b/README.md
index b274ac9..bbeee68 100644
--- a/README.md
+++ b/README.md
@@ -13,9 +13,11 @@ Usage
 # bundle install
 # irb -I lib
 
+require 'tictactoe'
+
 ttt = TicTacToe.new([["X", "X", "X"],
                      ["O", "O", "_"],
-                     ["O", "_","_"]]
+                     ["O", "_","_"]])
 
 ttt.winner # => "X"
 ```
diff --git a/lib/tictactoe.rb b/lib/tictactoe.rb
index 2b7b022..4b31de6 100644
--- a/lib/tictactoe.rb
+++ b/lib/tictactoe.rb
@@ -23,8 +23,8 @@ def in_coll?(config, player)
   end
 
   def in_diag?(config, player)
-    diag_indexes = [(0...size).zip((0...size))]
-    diag_indexes << (0...size).to_a.reverse.zip((0...size))
+    diag_indexes = [(0...size).to_a.zip((0...size).to_a)]
+    diag_indexes << (0...size).to_a.reverse.zip((0...size).to_a)
     diagonals = diag_indexes.map {|indexes| indexes.map { |x, y| config[x][y] } }
     in_row?(diagonals, player)
   end
diff --git a/test/tictactoe_test.rb b/test/tictactoe_test.rb
index 1d8d247..40275c9 100644
--- a/test/tictactoe_test.rb
+++ b/test/tictactoe_test.rb
@@ -1 +1,15 @@
 require 'test_helper'
+
+describe TicTacToe do
+
+	describe "X wins horizontally" do 
+		subject do
+			TicTacToe.new([["X", "X", "X"],
+                     ["O", "O", "_"],
+                     ["O", "_","_"]])
+		end
+		it "X must be the winner" do
+			subject.winner.must_equal "X"
+	end
+end
+end
\ No newline at end of file