FIX: Inappropriate error message when you couldn't access a topic

test/javascripts/acceptance/topic-anonymous-test.js.es6

@@ -15,3 +15,19 @@ test("Enter without an id", () => {
     ok(exists("#topic"), "The topic was rendered");
   });
 });
+
+test("Enter without access", (assert) => {
+  visit("/t/i-dont-have-access/403");
+  andThen(() => {
+    assert.ok(!exists("#topic"), "The topic was not rendered");
+    assert.ok(exists(".topic-error"), "An error message is displayed");
+  });
+});
+
+test("Enter with 500 errors", (assert) => {
+  visit("/t/throws-error/500");
+  andThen(() => {
+    assert.ok(!exists("#topic"), "The topic was not rendered");
+    assert.ok(exists(".topic-error"), "An error message is displayed");
+  });
+});

test/javascripts/helpers/create-pretender.js.es6

@@ -175,6 +175,14 @@ export default function() {
       return response(200, data.post);
     });
 
+    this.get('/t/403.json', () => {
+      return response(403, {});
+    });
+
+    this.get('/t/500.json', () => {
+      return response(502, {});
+    });
+
     this.put('/t/:slug/:id', (request) => {
       const data = parsePostData(request.requestBody);