Remove deprecated assert_blank and assert_present from tests

test/integration/oauth_test.rb

@@ -356,7 +356,7 @@ private
     params = CGI.parse(URI.parse(response.location).query)
 
     assert_not_nil params["oauth_verifier"]
-    assert_present params["oauth_verifier"].first
+    assert params["oauth_verifier"].first.present?
 
     params["oauth_verifier"].first
   end

test/unit/user_test.rb

@@ -231,7 +231,7 @@ class UserTest < ActiveSupport::TestCase
     user = users(:normal_user)
     user.delete
     assert_equal "user_#{user.id}", user.display_name
-    assert_blank user.description
+    assert user.description.blank?
     assert_equal nil, user.home_lat
     assert_equal nil, user.home_lon
     assert_equal false, user.image.file?