Revert "Raise error on unknown primary key."

This reverts commit ee2be435b1e5c0e94a4ee93a1a310e0471a77d07.

3 files changed, 4 insertions, 18 deletions

diff --git a/activerecord/test/cases/attribute_methods/read_test.rb b/activerecord/test/cases/attribute_methods/read_test.rb
index 814476ce73..e03ed33591 100644
--- a/activerecord/test/cases/attribute_methods/read_test.rb
+++ b/activerecord/test/cases/attribute_methods/read_test.rb
@@ -24,10 +24,6 @@ module ActiveRecord
           def self.primary_key
           end
 
-          def self.primary_key?
-            false
-          end
-
           def self.columns
             column_names.map { FakeColumn.new(name) }
           end
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 77fd1d2fad..12c1cfb30e 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -97,6 +97,10 @@ class BasicsTest < ActiveRecord::TestCase
     assert pk.primary, 'nick should be primary key'
   end
 
+  def test_primary_key_with_no_id
+    assert_nil Edge.primary_key
+  end
+
   unless current_adapter?(:PostgreSQLAdapter,:OracleAdapter,:SQLServerAdapter)
     def test_limit_with_comma
       assert_nothing_raised do
diff --git a/activerecord/test/cases/primary_keys_test.rb b/activerecord/test/cases/primary_keys_test.rb
index 58badd6266..489c7d8310 100644
--- a/activerecord/test/cases/primary_keys_test.rb
+++ b/activerecord/test/cases/primary_keys_test.rb
@@ -5,7 +5,6 @@ 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
@@ -162,17 +161,4 @@ 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