2 files changed, 34 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/fixture_set/file.rb b/activerecord/lib/active_record/fixture_set/file.rb
index fbd7a4d891..8132310c91 100644
--- a/activerecord/lib/active_record/fixture_set/file.rb
+++ b/activerecord/lib/active_record/fixture_set/file.rb
@@ -38,7 +38,8 @@ module ActiveRecord
         end
 
         def render(content)
-          ERB.new(content).result
+          context = ActiveRecord::FixtureSet::RenderContext.create_subclass.new
+          ERB.new(content).result(context.get_binding)
         end
 
         # Validate our unmarshalled data.
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 8601414209..d241788a9b 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -119,6 +119,23 @@ module ActiveRecord
   # perhaps you should reexamine whether your application is properly testable. Hence, dynamic values
   # in fixtures are to be considered a code smell.
   #
+  # Helper methods defined in a fixture will not be available in other fixtures, to prevent against
+  # unwanted inter-test dependencies. Methods used by multiple fixtures should be defined in a module
+  # that is included in <tt>ActiveRecord::FixtureSet.context_class</tt>.
+  #
+  # - define a helper method in `test_helper.rb`
+  #     class FixtureFileHelpers
+  #       def file_sha(path)
+  #         Digest::SHA2.hexdigest(File.read(Rails.root.join('test/fixtures', path)))
+  #       end
+  #     end
+  #     ActiveRecord::FixtureSet.context_class.send :include, FixtureFileHelpers
+  #
+  # - use the helper method in a fixture
+  #     photo:
+  #       name: kitten.png
+  #       sha: <%= file_sha 'files/kitten.png' %>
+  #
   # = Transactional Fixtures
   #
   # Test cases can use begin+rollback to isolate their changes to the database instead of having to
@@ -529,6 +546,11 @@ module ActiveRecord
       Zlib.crc32(label.to_s) % MAX_ID
     end
 
+    # Superclass for the evaluation contexts used by ERB fixtures.
+    def self.context_class
+      @context_class ||= Class.new
+    end
+
     attr_reader :table_name, :name, :fixtures, :model_class, :config
 
     def initialize(connection, name, class_name, path, config = ActiveRecord::Base)
@@ -989,3 +1011,13 @@ module ActiveRecord
       end
   end
 end
+
+class ActiveRecord::FixtureSet::RenderContext # :nodoc:
+  def self.create_subclass
+    Class.new ActiveRecord::FixtureSet.context_class do
+      def get_binding
+        binding()
+      end
+    end
+  end
+end