add hello_world test

week_3/page_controller_test.rb

@@ -0,0 +1,15 @@
+require "test_helper"
+
+class PageControllerTest < ActionDispatch::IntegrationTest
+  test "should get root" do
+    get '/'
+    assert_response :success
+
+    assert_select "h1", "Hello, World!"
+  end
+
+  test "should get about_me" do
+    get "/about_me"
+    assert_response :success
+  end
+end