3 files changed, 48 insertions, 0 deletions
diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
index 1a0732c14b..45bb58eb06 100644
--- a/activerecord/test/cases/autosave_association_test.rb
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -2,6 +2,7 @@
 
 require "cases/helper"
 require "models/author"
+require "models/book"
 require "models/bird"
 require "models/post"
 require "models/comment"
@@ -1685,6 +1686,10 @@ class TestAutosaveAssociationValidationsOnAHasManyAssociation < ActiveRecord::Te
     super
     @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
     @pirate.birds.create(name: "cookoo")
+
+    @author = Author.new(name: "DHH")
+    @author.published_books.build(name: "Rework", isbn: "1234")
+    @author.published_books.build(name: "Remote", isbn: "1234")
   end
 
   test "should automatically validate associations" do
@@ -1693,6 +1698,42 @@ class TestAutosaveAssociationValidationsOnAHasManyAssociation < ActiveRecord::Te
 
     assert_not_predicate @pirate, :valid?
   end
+
+  test "rollbacks whole transaction and raises ActiveRecord::RecordInvalid when associations fail to #save! due to uniqueness validation failure" do
+    author_count_before_save = Author.count
+    book_count_before_save = Book.count
+
+    assert_no_difference "Author.count" do
+      assert_no_difference "Book.count" do
+        exception = assert_raises(ActiveRecord::RecordInvalid) do
+          @author.save!
+        end
+
+        assert_equal("Validation failed: Published books is invalid", exception.message)
+      end
+    end
+
+    assert_equal(author_count_before_save, Author.count)
+    assert_equal(book_count_before_save, Book.count)
+  end
+
+  test "rollbacks whole transaction when associations fail to #save due to uniqueness validation failure" do
+    author_count_before_save = Author.count
+    book_count_before_save = Book.count
+
+    assert_no_difference "Author.count" do
+      assert_no_difference "Book.count" do
+        assert_nothing_raised do
+          result = @author.save
+
+          assert_not(result)
+        end
+      end
+    end
+
+    assert_equal(author_count_before_save, Author.count)
+    assert_equal(book_count_before_save, Book.count)
+  end
 end
 
 class TestAutosaveAssociationValidationsOnAHasOneAssociation < ActiveRecord::TestCase
diff --git a/activerecord/test/models/author.rb b/activerecord/test/models/author.rb
index b52b643ad7..da7e4139b1 100644
--- a/activerecord/test/models/author.rb
+++ b/activerecord/test/models/author.rb
@@ -116,6 +116,7 @@ class Author < ActiveRecord::Base
   has_many :tags_with_primary_key, through: :posts
 
   has_many :books
+  has_many :published_books, class_name: "PublishedBook"
   has_many :unpublished_books, -> { where(status: [:proposed, :written]) }, class_name: "Book"
   has_many :subscriptions,        through: :books
   has_many :subscribers, -> { order("subscribers.nick") }, through: :subscriptions
diff --git a/activerecord/test/models/book.rb b/activerecord/test/models/book.rb
index afdda1a81e..43b82e6047 100644
--- a/activerecord/test/models/book.rb
+++ b/activerecord/test/models/book.rb
@@ -24,3 +24,9 @@ class Book < ActiveRecord::Base
     "do publish work..."
   end
 end
+
+class PublishedBook < ActiveRecord::Base
+  self.table_name = "books"
+
+  validates_uniqueness_of :isbn
+end