4 files changed, 31 insertions, 23 deletions
diff --git a/activerecord/test/cases/ar_schema_test.rb b/activerecord/test/cases/ar_schema_test.rb
index aa5b27623e..244e0b7179 100644
--- a/activerecord/test/cases/ar_schema_test.rb
+++ b/activerecord/test/cases/ar_schema_test.rb
@@ -12,6 +12,7 @@ if ActiveRecord::Base.connection.supports_migrations?
 
     def teardown
       @connection.drop_table :fruits rescue nil
+      ActiveRecord::SchemaMigration.delete_all rescue nil
     end
 
     def test_schema_define
diff --git a/activerecord/test/cases/associations/nested_through_associations_test.rb b/activerecord/test/cases/associations/nested_through_associations_test.rb
index 03d99d19f6..e355ed3495 100644
--- a/activerecord/test/cases/associations/nested_through_associations_test.rb
+++ b/activerecord/test/cases/associations/nested_through_associations_test.rb
@@ -221,6 +221,9 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_has_many_through_has_many_with_has_and_belongs_to_many_source_reflection_preload_via_joins
+    # preload table schemas
+    Author.joins(:post_categories).first
+
     assert_includes_and_joins_equal(
       Author.where('categories.id' => categories(:cooking).id),
       [authors(:bob)], :post_categories
@@ -246,6 +249,9 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_has_many_through_has_and_belongs_to_many_with_has_many_source_reflection_preload_via_joins
+    # preload table schemas
+    Category.joins(:post_comments).first
+
     assert_includes_and_joins_equal(
       Category.where('comments.id' => comments(:more_greetings).id).order('categories.id'),
       [categories(:general), categories(:technology)], :post_comments
@@ -271,6 +277,9 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_has_many_through_has_many_with_has_many_through_habtm_source_reflection_preload_via_joins
+    # preload table schemas
+    Author.joins(:category_post_comments).first
+
     assert_includes_and_joins_equal(
       Author.where('comments.id' => comments(:does_it_hurt).id).order('authors.id'),
       [authors(:david), authors(:mary)], :category_post_comments
diff --git a/activerecord/test/cases/dup_test.rb b/activerecord/test/cases/dup_test.rb
index 4e2adff344..eca500f7e4 100644
--- a/activerecord/test/cases/dup_test.rb
+++ b/activerecord/test/cases/dup_test.rb
@@ -108,18 +108,20 @@ module ActiveRecord
     end
 
     def test_dup_validity_is_independent
-      Topic.validates_presence_of :title
-      topic = Topic.new("title" => "Litterature")
-      topic.valid?
-
-      duped = topic.dup
-      duped.title = nil
-      assert duped.invalid?
-
-      topic.title = nil
-      duped.title = 'Mathematics'
-      assert topic.invalid?
-      assert duped.valid?
+      repair_validations(Topic) do
+        Topic.validates_presence_of :title
+        topic = Topic.new("title" => "Litterature")
+        topic.valid?
+
+        duped = topic.dup
+        duped.title = nil
+        assert duped.invalid?
+
+        topic.title = nil
+        duped.title = 'Mathematics'
+        assert topic.invalid?
+        assert duped.valid?
+      end
     end
   end
 end
diff --git a/activerecord/test/cases/migration_test.rb b/activerecord/test/cases/migration_test.rb
index 187c6e8447..fa8dec0e15 100644
--- a/activerecord/test/cases/migration_test.rb
+++ b/activerecord/test/cases/migration_test.rb
@@ -30,9 +30,13 @@ class MigrationTest < ActiveRecord::TestCase
     Reminder.reset_column_information
     ActiveRecord::Migration.verbose = true
     ActiveRecord::Migration.message_count = 0
+    ActiveRecord::Base.connection.schema_cache.clear!
   end
 
   def teardown
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+
     ActiveRecord::Base.connection.initialize_schema_migrations_table
     ActiveRecord::Base.connection.execute "DELETE FROM #{ActiveRecord::Migrator.schema_migrations_table_name}"
 
@@ -44,6 +48,7 @@ class MigrationTest < ActiveRecord::TestCase
     %w(reminders people_reminders prefix_reminders_suffix).each do |table|
       Reminder.connection.drop_table(table) rescue nil
     end
+    Reminder.reset_table_name
     Reminder.reset_column_information
 
     %w(last_name key bio age height wealth birthday favorite_day
@@ -257,9 +262,6 @@ class MigrationTest < ActiveRecord::TestCase
     ActiveRecord::Base.table_name_suffix = ""
     Reminder.reset_table_name
     assert_equal "schema_migrations", ActiveRecord::Migrator.schema_migrations_table_name
-  ensure
-    ActiveRecord::Base.table_name_prefix = ""
-    ActiveRecord::Base.table_name_suffix = ""
   end
 
   def test_proper_table_name
@@ -286,9 +288,6 @@ class MigrationTest < ActiveRecord::TestCase
     Reminder.reset_table_name
     assert_equal "prefix_table_suffix", ActiveRecord::Migrator.proper_table_name('table')
     assert_equal "prefix_table_suffix", ActiveRecord::Migrator.proper_table_name(:table)
-    ActiveRecord::Base.table_name_prefix = ""
-    ActiveRecord::Base.table_name_suffix = ""
-    Reminder.reset_table_name
   end
 
   def test_rename_table_with_prefix_and_suffix
@@ -307,8 +306,6 @@ class MigrationTest < ActiveRecord::TestCase
 
     assert_equal "hello world", Thing.first.content
   ensure
-    ActiveRecord::Base.table_name_prefix = ''
-    ActiveRecord::Base.table_name_suffix = ''
     Thing.reset_table_name
     Thing.reset_sequence_name
   end
@@ -326,9 +323,6 @@ class MigrationTest < ActiveRecord::TestCase
     WeNeedReminders.down
     assert_raise(ActiveRecord::StatementInvalid) { Reminder.first }
   ensure
-    ActiveRecord::Base.table_name_prefix = ''
-    ActiveRecord::Base.table_name_suffix = ''
-    Reminder.reset_table_name
     Reminder.reset_sequence_name
   end
 
@@ -437,6 +431,8 @@ if ActiveRecord::Base.connection.supports_bulk_alter?
     def setup
       @connection = Person.connection
       @connection.create_table(:delete_me, :force => true) {|t| }
+      Person.reset_column_information
+      Person.reset_sequence_name
     end
 
     def teardown