1 files changed, 82 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/fixture_set/file.rb b/activerecord/lib/active_record/fixture_set/file.rb
new file mode 100644
index 0000000000..f1ea0e022f
--- /dev/null
+++ b/activerecord/lib/active_record/fixture_set/file.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+require "erb"
+require "yaml"
+
+module ActiveRecord
+  class FixtureSet
+    class File # :nodoc:
+      include Enumerable
+
+      ##
+      # Open a fixture file named +file+.  When called with a block, the block
+      # is called with the filehandle and the filehandle is automatically closed
+      # when the block finishes.
+      def self.open(file)
+        x = new file
+        block_given? ? yield(x) : x
+      end
+
+      def initialize(file)
+        @file = file
+      end
+
+      def each(&block)
+        rows.each(&block)
+      end
+
+      def model_class
+        config_row["model_class"]
+      end
+
+      private
+        def rows
+          @rows ||= raw_rows.reject { |fixture_name, _| fixture_name == "_fixture" }
+        end
+
+        def config_row
+          @config_row ||= begin
+            row = raw_rows.find { |fixture_name, _| fixture_name == "_fixture" }
+            if row
+              row.last
+            else
+              { 'model_class': nil }
+            end
+          end
+        end
+
+        def raw_rows
+          @raw_rows ||= begin
+            data = YAML.load(render(IO.read(@file)))
+            data ? validate(data).to_a : []
+          rescue ArgumentError, Psych::SyntaxError => error
+            raise Fixture::FormatError, "a YAML error occurred parsing #{@file}. Please note that YAML must be consistently indented using spaces. Tabs are not allowed. Please have a look at http://www.yaml.org/faq.html\nThe exact error was:\n  #{error.class}: #{error}", error.backtrace
+          end
+        end
+
+        def prepare_erb(content)
+          erb = ERB.new(content)
+          erb.filename = @file
+          erb
+        end
+
+        def render(content)
+          context = ActiveRecord::FixtureSet::RenderContext.create_subclass.new
+          prepare_erb(content).result(context.get_binding)
+        end
+
+        # Validate our unmarshalled data.
+        def validate(data)
+          unless Hash === data || YAML::Omap === data
+            raise Fixture::FormatError, "fixture is not a hash: #{@file}"
+          end
+
+          invalid = data.reject { |_, row| Hash === row }
+          if invalid.any?
+            raise Fixture::FormatError, "fixture key is not a hash: #{@file}, keys: #{invalid.keys.inspect}"
+          end
+          data
+        end
+    end
+  end
+end