Hash#slice supports an array of keys [#613 state:resolved]

Signed-off-by: NJoshua Peek <josh@joshpeek.com>

activesupport/lib/active_support/core_ext/hash/slice.rb

@@ -12,6 +12,7 @@ module Hash #:nodoc:
       module Slice
         # Returns a new hash with only the given keys.
         def slice(*keys)
+          keys.flatten!
           keys = keys.map! { |key| convert_key(key) } if respond_to?(:convert_key)
           hash = {}
           keys.each { |k| hash[k] = self[k] if has_key?(k) }

activesupport/test/core_ext/hash_ext_test.rb

@@ -282,6 +282,20 @@ def test_slice
     assert_equal expected, original
   end
 
+  # This is needed for something like hash.slice!(hash.keys.sort_by {rand} [0..4])
+  def test_slice_with_array_keys
+    original = { :a => 'x', :b => 'y', :c => 10 }
+    expected = { :a => 'x', :b => 'y' }
+
+    # Should return a new hash with only the given keys, when given an array of keys.
+    assert_equal expected, original.slice([:a, :b])
+    assert_not_equal expected, original
+
+    # Should replace the hash with only the given keys, when given an array of keys.
+    assert_equal expected, original.slice!([:a, :b])
+    assert_equal expected, original
+  end
+
   def test_indifferent_slice
     original = { :a => 'x', :b => 'y', :c => 10 }.with_indifferent_access
     expected = { :a => 'x', :b => 'y' }.with_indifferent_access