2 files changed, 66 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index 96dc258288..13b7c6e214 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -72,9 +72,13 @@ module ActiveRecord
     # and then establishes the connection.
     initializer "active_record.initialize_database" do |app|
       ActiveSupport.on_load(:active_record) do
+        db_connection_type = "DATABASE_URL"
         unless ENV['DATABASE_URL']
+          db_connection_type  = "database.yml"
           self.configurations = app.config.database_configuration
         end
+        Rails.logger.info "Connecting to database specified by #{db_connection_type}"
+
         establish_connection
       end
     end
diff --git a/railties/test/application/initializers/active_record_test.rb b/railties/test/application/initializers/active_record_test.rb
new file mode 100644
index 0000000000..edf78a8a0a
--- /dev/null
+++ b/railties/test/application/initializers/active_record_test.rb
@@ -0,0 +1,62 @@
+require "isolation/abstract_unit"
+require "rack/test"
+
+module ApplicationTests
+  class ActiveRecordTest < Test::Unit::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      @database_url = ENV['DATABASE_URL']
+      ENV.delete('DATABASE_URL')
+      build_app
+      boot_rails
+    end
+
+    def teardown
+      teardown_app
+      ENV['DATABASE_URL'] = @database_url
+    end
+
+    test "blows up when no DATABASE_URL env var or database.yml" do
+      FileUtils.rm_rf("#{app_path}/config/database.yml")
+      boot_rails
+      simple_controller
+
+      get '/foo'
+      assert last_response.body.include?("We're sorry, but something went wrong (500)")
+    end
+    
+    test "uses DATABASE_URL env var when config/database.yml doesn't exist" do
+      database_path = "/db/foo.sqlite3"
+      FileUtils.rm_rf("#{app_path}/config/database.yml")
+      ENV['DATABASE_URL'] = "sqlite3://#{database_path}"
+      simple_controller
+
+      get '/foo'
+      assert_equal 'foo', last_response.body
+      
+      # clean up
+      FileUtils.rm("#{app_path}/#{database_path}")
+    end
+
+    test "DATABASE_URL env var takes precedence over config/database.yml" do
+      database_path = "/db/foo.sqlite3"
+      ENV['DATABASE_URL'] = "sqlite3://#{database_path}"
+      simple_controller
+
+      get '/foo'
+      assert File.read("#{app_path}/log/production.log").include?("DATABASE_URL")
+
+      # clean up
+      FileUtils.rm("#{app_path}/#{database_path}")
+    end
+
+    test "logs the use of config/database.yml" do
+      simple_controller
+
+      get '/foo'
+      assert File.read("#{app_path}/log/production.log").include?("database.yml")
+    end
+  end
+end