Raise error on unknown primary key.

If we don't have a primary key when we ask for it, it's better to fail
fast. Fixes GH #2307.

1 files changed, 14 insertions, 0 deletions

diff --git a/activerecord/test/cases/primary_keys_test.rb b/activerecord/test/cases/primary_keys_test.rb
index 489c7d8310..58badd6266 100644
--- a/activerecord/test/cases/primary_keys_test.rb
+++ b/activerecord/test/cases/primary_keys_test.rb
@@ -5,6 +5,7 @@ require 'models/subscriber'
 require 'models/movie'
 require 'models/keyboard'
 require 'models/mixed_case_monkey'
+require 'models/edge'
 
 class PrimaryKeysTest < ActiveRecord::TestCase
   fixtures :topics, :subscribers, :movies, :mixed_case_monkeys
@@ -161,4 +162,17 @@ class PrimaryKeysTest < ActiveRecord::TestCase
 
     assert_equal 'foo', model.primary_key
   end
+
+  def test_no_primary_key_raises
+    assert_raises(ActiveRecord::UnknownPrimaryKey) do
+      Edge.primary_key
+    end
+
+    begin
+      Edge.primary_key
+    rescue ActiveRecord::UnknownPrimaryKey => e
+      assert e.message.include?('edges')
+      assert e.message.include?('Edge')
+    end
+  end
 end