Policy変更に伴い、テストも修正

・app/policies/submission_answer_policy.rb

test/system/practice/submission_answer_test.rb

@@ -7,18 +7,21 @@ class Practice::SubmissionAnswerTest < ApplicationSystemTestCase
     @practice = practices(:practice1)
   end
 
-  test 'student passed practice can show submission answer' do
-    visit_with_auth practice_path(@practice), 'kimura'
-    assert find_button('修了')[:disabled]
-    visit practice_submission_answer_path(@practice)
+  test 'student passed practice and product can show submission answer' do
+    user = User.find_by(login_name: 'kimura')
+    visit_with_auth practice_path(@practice), user.login_name
+    assert @practice.product(user).checked?
+    assert find_button('修了', disabled: true)
+    click_on '模範解答'
     assert_text '「OS X Mountain Lionをクリーンインストールする」の模範解答'
     assert_text 'description...'
   end
 
-  test 'student not passed practice can not show submission answer' do
-    visit_with_auth practice_path(@practice), 'kimura'
-    click_on '未着手'
-    assert find_button('未着手')[:disabled]
+  test 'student not passed practice and product can not show submission answer' do
+    user = User.find_by(login_name: 'kensyu')
+    visit_with_auth practice_path(@practice), user.login_name
+    assert_not @practice.product(user).checked?
+    assert find_button('未着手', disabled: true)
     visit practice_submission_answer_path(@practice)
     assert_text 'プラクティスを修了するまで模範解答は見れません。'
   end