UX: Display button to message group on group page.

https://meta.discourse.org/t/make-it-easier-to-send-a-message-to-groups/65065

test/javascripts/acceptance/groups-test.js.es6

@@ -42,12 +42,13 @@ QUnit.test("Browsing Groups", assert => {
   });
 });
 
-QUnit.test("Viewing Group", assert => {
+QUnit.test("Anonymous Viewing Group", assert => {
   visit("/groups/discourse");
 
   andThen(() => {
     assert.ok(count('.avatar-flair .fa-adjust') === 1, "it displays the group's avatar flair");
     assert.ok(count('.group-members tr') > 0, "it lists group members");
+    assert.ok(count('.group-message-button') === 0, 'it does not show group message button');
   });
 
   click(".nav-pills li a[title='Activity']");
@@ -80,6 +81,20 @@ QUnit.test("Viewing Group", assert => {
   });
 });
 
+QUnit.test("User Viewing Group", assert => {
+  logIn();
+  Discourse.reset();
+
+  visit("/groups/discourse");
+
+  click('.group-message-button');
+
+  andThen(() => {
+    assert.ok(count('#reply-control') === 1, 'it opens the composer');
+    assert.equal(find('.ac-wrap .item').text(), 'discourse', 'it prefills the group name');
+  });
+});
+
 QUnit.test("Admin Viewing Group", assert => {
   logIn();
   Discourse.reset();
@@ -102,4 +117,4 @@ QUnit.test("Admin Viewing Group", assert => {
       'it should show messages tab if user is admin'
     );
   });
-});
+});

test/javascripts/fixtures/group-fixtures.js.es6

@@ -6,11 +6,12 @@ export default {
       "name":"discourse",
       "full_name":"Awesome Team",
       "user_count":8,
-      "alias_level":0,
+      "alias_level":99,
       "visible":true,
       "public":true,
       "flair_url": 'fa-adjust',
-      "is_group_owner":true
+      "is_group_owner":true,
+      "mentionable":true
     }
   },
   "/groups/discourse/counts.json":{