1 files changed, 61 insertions, 0 deletions
diff --git a/activerecord/test/cases/attribute_methods/read_test.rb b/activerecord/test/cases/attribute_methods/read_test.rb
new file mode 100644
index 0000000000..54512068ee
--- /dev/null
+++ b/activerecord/test/cases/attribute_methods/read_test.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module AttributeMethods
+    class ReadTest < ActiveRecord::TestCase
+      FakeColumn = Struct.new(:name) do
+        def type; :integer; end
+      end
+
+      def setup
+        @klass = Class.new(Class.new { def self.initialize_generated_modules; end }) do
+          def self.superclass; Base; end
+          def self.base_class?; true; end
+          def self.decorate_matching_attribute_types(*); end
+
+          include ActiveRecord::DefineCallbacks
+          include ActiveRecord::AttributeMethods
+
+          def self.attribute_names
+            %w{ one two three }
+          end
+
+          def self.primary_key
+          end
+
+          def self.columns
+            attribute_names.map { FakeColumn.new(name) }
+          end
+
+          def self.columns_hash
+            Hash[attribute_names.map { |name|
+              [name, FakeColumn.new(name)]
+            }]
+          end
+        end
+      end
+
+      def test_define_attribute_methods
+        instance = @klass.new
+
+        @klass.attribute_names.each do |name|
+          assert_not_includes instance.methods.map(&:to_s), name
+        end
+
+        @klass.define_attribute_methods
+
+        @klass.attribute_names.each do |name|
+          assert_includes instance.methods.map(&:to_s), name, "#{name} is not defined"
+        end
+      end
+
+      def test_attribute_methods_generated?
+        assert_not @klass.method_defined?(:one)
+        @klass.define_attribute_methods
+        assert @klass.method_defined?(:one)
+      end
+    end
+  end
+end