Added new enable labs flag helper for tests

no refs

- allows easily enabling alpha features for tests

ghost/admin/tests/helpers/enable-labs-flag.js

@@ -0,0 +1,11 @@
+export default function (server, flag) {
+    server.loadFixtures('configs');
+    const config = server.schema.configs.first();
+    config.update({enableDeveloperExperiments: true});
+
+    const labsSetting = {};
+    labsSetting[flag] = true;
+
+    server.loadFixtures('settings');
+    server.db.settings.update({key: 'labs'}, {value: JSON.stringify(labsSetting)});
+}