FEATURE: Support [description|attachment](upload://<short-sha>) in MD. (#7603)

test/javascripts/acceptance/composer-attachment-test.js.es6

@@ -0,0 +1,39 @@
+import { acceptance } from "helpers/qunit-helpers";
+
+acceptance("Composer Attachment", {
+  loggedIn: true,
+  pretend(server, helper) {
+    server.post("/uploads/lookup-urls", () => {
+      return helper.response([
+        {
+          short_url: "upload://asdsad.png",
+          url: "/uploads/default/3X/1/asjdiasjdiasida.png",
+          short_path: "/uploads/short-url/asdsad.png"
+        }
+      ]);
+    });
+  }
+});
+
+QUnit.test("attachments are cooked properly", async assert => {
+  await visit("/t/internationalization-localization/280");
+  await click("#topic-footer-buttons .btn.create");
+
+  await fillIn(".d-editor-input", "[test](upload://abcdefg.png)");
+
+  assert.equal(
+    find(".d-editor-preview:visible")
+      .html()
+      .trim(),
+    '<p><a href="/404">test</a></p>'
+  );
+
+  await fillIn(".d-editor-input", "[test|attachment](upload://asdsad.png)");
+
+  assert.equal(
+    find(".d-editor-preview:visible")
+      .html()
+      .trim(),
+    '<p><a href="/uploads/short-url/asdsad.png" class="attachment">test</a></p>'
+  );
+});