Add check whether problem has a translation

test/controllers/problems_controller_test.rb

@@ -11,4 +11,9 @@ class ProblemsControllerTest < ActionController::TestCase
     assert_response :success
   end
 
+  test "should get untranslated problem" do
+    get :show, id: 3
+    assert_response :success
+  end
+
 end

test/fixtures/problems.yml

@@ -7,3 +7,7 @@ one:
 two:
   id: 2
   translation_id: <%= ActiveRecord::FixtureSet.identify(:translation_two) %>
+
+three:
+  id: 3
+

test/models/problem_test.rb

@@ -1,7 +1,16 @@
 require 'test_helper'
 
 class ProblemTest < ActiveSupport::TestCase
-  # test "the truth" do
-  #   assert true
-  # end
+  test "should save correct problem" do
+    problem = Problem.new
+    assert problem.save
+  end
+
+  test "is_translated? should return false for missing translation" do
+    assert_not problems(:three).is_translated?
+  end
+
+  test "is_translated? should return true for existing translation" do
+    assert problems(:one).is_translated?
+  end
 end