Fix behaviour when array of ids is passed to find

The original rails find allows an array of ids to be passed to the find method. However, the find method in prefix_ids doesn't. This change makes the find method compliant with what the default rails method does.

lib/prefixed_ids.rb

@@ -91,14 +91,15 @@ module Finder
 
     class_methods do
       def find(*ids)
-        prefix_ids = *ids.map do |id|
+        prefix_ids = *ids.flatten.map do |id|
           # Skip if model doesn't use prefixed ids
           next id unless _prefix_id.present?
 
           prefix_id = _prefix_id.decode(id, fallback: _prefix_id_fallback)
           raise Error, "#{id} is not a valid prefix_id" if !_prefix_id_fallback && prefix_id.nil?
           prefix_id
         end
+        prefix_ids = [prefix_ids] if ids.first.is_a?(Array)
         super(*prefix_ids)
       end
 

test/prefixed_ids_test.rb

@@ -65,6 +65,17 @@ class PrefixedIdsTest < ActiveSupport::TestCase
     assert_equal [user, user2], User.find(user.prefix_id, user2.prefix_id)
   end
 
+  test "overridden finders with array args" do
+    user = users(:one)
+    user2 = users(:two)
+    assert_equal [user, user2], User.find([user.prefix_id, user2.prefix_id])
+  end
+
+  test "overridden finders with single array args" do
+    user = users(:one)
+    assert_equal [user], User.find([user.prefix_id])
+  end
+
   test "minimum length" do
     assert_equal 32 + 5, accounts(:one).prefix_id.length
   end