diff --git a/courses/ruby/ex04-myattr/my_attr_accessor_test.rb b/courses/ruby/ex04-myattr/my_attr_accessor_test.rb
index e69de29b..16898038 100644
--- a/courses/ruby/ex04-myattr/my_attr_accessor_test.rb
+++ b/courses/ruby/ex04-myattr/my_attr_accessor_test.rb
@@ -0,0 +1,46 @@
+
+require 'openssl'
+require 'base64'
+require "minitest/autorun"
+require "minitest/pride"
+require_relative "my_attr_accessor"
+
+class MyAttrAccessorTest < Minitest::Test
+  Module.prepend MyAcc
+  def test_single_my_attr_accessor
+    klass = Class.new do
+      my_attr_accessor(:acc, "./user_key.txt")
+    end
+    instance = klass.new
+    instance.acc_set = "d2hdmnHxYJcxsajeblGv92vPgtBo8nxQ+nvPzZwNlLf7HEYWRo79aTiFJkusT/mbcVkKv/MPwRc0zil7YwbaQB733KgVduq1OHCXtAoc8P2fRHprvYE3nsru5Iz+fYPo46afEqnd8kqjIg44cLjobS+Y9p+/iJAcFripStM86bk=.B8lIigGs9fanDbEZfijgJG/42wxEzVpNQrK379lQdBolCEZsD2cTEW5cCY8pVnSEi2xO4Sj/tKW4nJvgxL/UkqmFI/jyBKfMexMTzFb8w7audRq99E0DlmJ9t6OQhkmIUN1aqeZOUMbOxd5WnxSNsBxUSf64v1ntErRSl3KfBD4="
+    assert_equal "Hello World!", instance.acc
+  end
+
+  def test_wrong_signature_my_attr_accessor
+    klass = Class.new do
+      my_attr_accessor(:acc, "./user_key.txt")
+    end
+    instance = klass.new
+    instance.acc_set = "d2hdmnHxYJcxsajeblGv92vPgtBo8nxQ+nvPzZwNlLf7HEYWRo79aTiFJkusT/mbcVkKv/MPwRc0zil7YwbaQB733KgVduq1OHCXtAoc8P2fRHprvYE3nsru5Iz+fYPo46afEqnd8kqjIg44cLjobS+Y9p+/iJAcFripStM86bk=.B2lIigGs9fanDbEZfijgJG/42wxEzVpNQrK379lQdBolCEZsD2cTEW5cCY8pVnSEi2xO4Sj/tKW4nJvgxL/UkqmFI/jyBKfMexMTzFb8w7audRq99E0DlmJ9t6OQhkmIUN1aqeZOUMbOxd5WnxSNsBxUSf64v1ntErRSl3KfBD4="
+    msg = instance.acc
+    assert_equal "Error", msg
+  end
+
+  def test_wrong_key_my_attr_accessor
+    klass = Class.new do
+      my_attr_accessor(:acc, "./user_key.txt")
+    end
+    instance = klass.new
+    instance.acc_set = "cHNfFM+Y6ap8e6ExiGuVbaeqVdJe9KwoQwAWqdmkGvyRA4SAP0BPuPrp7P2lSEjbN5WMzEYuERZ6fxgbA83rx+hOov8YdQ0TYk34mbTaC3KOdPIduSvRHc3196nyCa752Jvyc8VeNHdt5brq32jDqrMTaej8QnzGJx3p6NuP3nY=.JyKEo41d+xCbsDqhdkW2Ex/kpVjnIy8x5RcSE55V0nOcoKFTRgTdEivE6A9X1U3HAi1usGFnv/6QiSPsBUxkxEafnPHVpX62BR1k293+81L8iaYUQsniz9MDoEHStwsFGnc+YktOQksKTmu9JR29BPTpk7lwkEeYQmT8L748sfg="
+    msg = instance.acc
+    assert_equal "Wrong Key", msg
+  end
+
+  def test_no_file_my_attr_accessor
+    klass = Class.new do
+      @@msg=my_attr_accessor(:acc, nil)
+    end
+    instance = klass.new
+    assert_equal "File not found", @@msg
+  end
+end