[FIX] better control on value mutation

test/javascripts/components/select-box-test.js.es6

@@ -275,3 +275,19 @@ componentTest('supports keyboard events', {
     });
   }
 });
+
+
+componentTest('supports mutating value when no value given', {
+  template: '{{select-box-kit value=value content=content}}',
+
+  beforeEach() {
+    this.set("value", "");
+    this.set("content", [{ id: "1", name: "robin"}, {id: "2", name: "régis" }]);
+  },
+
+  test(assert) {
+    andThen(() => {
+      assert.equal(this.get("value"), "1");
+    });
+  }
+});

test/javascripts/components/topic-footer-mobile-dropdown-test.js.es6

@@ -23,6 +23,13 @@ componentTest('default', {
       assert.equal(selectBox().header.name(), "Topic Controls");
       assert.equal(selectBox().rowByIndex(0).name(), "Bookmark");
       assert.equal(selectBox().rowByIndex(1).name(), "Share");
+      assert.equal(selectBox().selectedRow.el.length, 0, "it doesn’t preselect first row");
+    });
+
+    selectBoxSelectRow("share");
+
+    andThen(() => {
+      assert.equal(this.get("value"), null, "it resets the value");
     });
   }
 });