Change JoinPart test from an integration to a unit test

activerecord/test/cases/associations/eager_test.rb

@@ -39,19 +39,6 @@ def test_eager_with_has_one_through_join_model_with_conditions_on_the_through
     assert_nil member.favourite_club
   end
 
-  def test_loading_with_one_association_without_primary_key
-    Comment.primary_key = nil
-    begin
-      assert_nothing_raised do
-        Post.includes(:comments).references(:comments).all
-      end
-    rescue
-      raise $!
-    ensure
-      Comment.primary_key = 'id'
-    end
-  end
-
   def test_loading_with_one_association
     posts = Post.find(:all, :include => :comments)
     post = posts.find { |p| p.id == 1 }

activerecord/test/cases/associations/join_dependency_test.rb

@@ -0,0 +1,8 @@
+require "cases/helper"
+require 'models/edge'
+
+class JoinDependencyTest < ActiveRecord::TestCase
+  def test_column_names_with_alias_handles_nil_primary_key
+    assert_equal Edge.column_names, ActiveRecord::Associations::JoinDependency::JoinBase.new(Edge).column_names_with_alias.map(&:first)
+  end
+end