Allow passing named parameters to testAction function

This might need a better docstring update, could also
be done in a nicer way

spec/frontend/helpers/vuex_action_helper.js

@@ -4,7 +4,7 @@ const noop = () => {};
  * Helper for testing action with expected mutations inspired in
  * https://vuex.vuejs.org/en/testing.html
  *
- * @param {Function} action to be tested
+ * @param {(Function|Object)} action to be tested, or object of named parameters
  * @param {Object} payload will be provided to the action
  * @param {Object} state will be provided to the action
  * @param {Array} [expectedMutations=[]] mutations expected to be committed
@@ -39,15 +39,42 @@ const noop = () => {};
  *   [], // expected actions
  * ).then(done)
  * .catch(done.fail);
+ *
+ * @example
+ * await testAction({
+ *   action: actions.actionName,
+ *   payload: { deleteListId: 1 },
+ *   state: { lists: [1, 2, 3] },
+ *   expectedMutations: [ { type: types.MUTATION} ],
+ *   expectedActions: [],
+ * })
  */
 export default (
+  actionArg,
+  payloadArg,
+  stateArg,
+  expectedMutationsArg = [],
+  expectedActionsArg = [],
+  doneArg = noop,
+) => {
+  let action = actionArg;
+  let payload = payloadArg;
+  let state = stateArg;
+  let expectedMutations = expectedMutationsArg;
+  let expectedActions = expectedActionsArg;
+  let done = doneArg;
+
+  if (typeof actionArg !== 'function') {
+    ({
       action,
       payload,
       state,
       expectedMutations = [],
       expectedActions = [],
       done = noop,
-) => {
+    } = actionArg);
+  }
+
   const mutations = [];
   const actions = [];
 

spec/frontend/helpers/vuex_action_helper_spec.js

 import MockAdapter from 'axios-mock-adapter';
 import { TEST_HOST } from 'helpers/test_constants';
 import axios from '~/lib/utils/axios_utils';
-import testAction from './vuex_action_helper';
+import testActionFn from './vuex_action_helper';
 
-describe('VueX test helper (testAction)', () => {
+const testActionFnWithOptionsArg = (...args) => {
+  const [action, payload, state, expectedMutations, expectedActions, done] = args;
+  return testActionFn({ action, payload, state, expectedMutations, expectedActions, done });
+};
+
+describe.each([testActionFn, testActionFnWithOptionsArg])(
+  'VueX test helper (testAction)',
+  testAction => {
     let originalExpect;
     let assertion;
     let mock;
@@ -163,4 +170,5 @@ describe('VueX test helper (testAction)', () => {
 
       testAction(asyncAction, null, {}, assertion.mutations, assertion.actions, done);
     });
-});
+  },
+);