1 files changed, 166 insertions, 0 deletions
diff --git a/spec/frontend/helpers/vuex_action_helper_spec.js b/spec/frontend/helpers/vuex_action_helper_spec.js
new file mode 100644
index 00000000000..61d05762a04
--- /dev/null
+++ b/spec/frontend/helpers/vuex_action_helper_spec.js
@@ -0,0 +1,166 @@
+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';
+
+describe('VueX test helper (testAction)', () => {
+  let originalExpect;
+  let assertion;
+  let mock;
+  const noop = () => {};
+
+  beforeEach(() => {
+    mock = new MockAdapter(axios);
+    /**
+     * In order to test the helper properly, we need to overwrite the Jest
+     * `expect` helper.  We test that the testAction helper properly passes the
+     * dispatched actions/committed mutations to the Jest helper.
+     */
+    originalExpect = expect;
+    assertion = null;
+    global.expect = actual => ({
+      toEqual: () => {
+        originalExpect(actual).toEqual(assertion);
+      },
+    });
+  });
+
+  afterEach(() => {
+    mock.restore();
+    global.expect = originalExpect;
+  });
+
+  it('properly passes state and payload to action', () => {
+    const exampleState = { FOO: 12, BAR: 3 };
+    const examplePayload = { BAZ: 73, BIZ: 55 };
+
+    const action = ({ state }, payload) => {
+      originalExpect(state).toEqual(exampleState);
+      originalExpect(payload).toEqual(examplePayload);
+    };
+
+    assertion = { mutations: [], actions: [] };
+
+    testAction(action, examplePayload, exampleState);
+  });
+
+  describe('given a sync action', () => {
+    it('mocks committing mutations', () => {
+      const action = ({ commit }) => {
+        commit('MUTATION');
+      };
+
+      assertion = { mutations: [{ type: 'MUTATION' }], actions: [] };
+
+      testAction(action, null, {}, assertion.mutations, assertion.actions, noop);
+    });
+
+    it('mocks dispatching actions', () => {
+      const action = ({ dispatch }) => {
+        dispatch('ACTION');
+      };
+
+      assertion = { actions: [{ type: 'ACTION' }], mutations: [] };
+
+      testAction(action, null, {}, assertion.mutations, assertion.actions, noop);
+    });
+
+    it('works with done callback once finished', done => {
+      assertion = { mutations: [], actions: [] };
+
+      testAction(noop, null, {}, assertion.mutations, assertion.actions, done);
+    });
+
+    it('returns a promise', done => {
+      assertion = { mutations: [], actions: [] };
+
+      testAction(noop, null, {}, assertion.mutations, assertion.actions)
+        .then(done)
+        .catch(done.fail);
+    });
+  });
+
+  describe('given an async action (returning a promise)', () => {
+    let lastError;
+    const data = { FOO: 'BAR' };
+
+    const asyncAction = ({ commit, dispatch }) => {
+      dispatch('ACTION');
+
+      return axios
+        .get(TEST_HOST)
+        .catch(error => {
+          commit('ERROR');
+          lastError = error;
+          throw error;
+        })
+        .then(() => {
+          commit('SUCCESS');
+          return data;
+        });
+    };
+
+    beforeEach(() => {
+      lastError = null;
+    });
+
+    it('works with done callback once finished', done => {
+      mock.onGet(TEST_HOST).replyOnce(200, 42);
+
+      assertion = { mutations: [{ type: 'SUCCESS' }], actions: [{ type: 'ACTION' }] };
+
+      testAction(asyncAction, null, {}, assertion.mutations, assertion.actions, done);
+    });
+
+    it('returns original data of successful promise while checking actions/mutations', done => {
+      mock.onGet(TEST_HOST).replyOnce(200, 42);
+
+      assertion = { mutations: [{ type: 'SUCCESS' }], actions: [{ type: 'ACTION' }] };
+
+      testAction(asyncAction, null, {}, assertion.mutations, assertion.actions)
+        .then(res => {
+          originalExpect(res).toEqual(data);
+          done();
+        })
+        .catch(done.fail);
+    });
+
+    it('returns original error of rejected promise while checking actions/mutations', done => {
+      mock.onGet(TEST_HOST).replyOnce(500, '');
+
+      assertion = { mutations: [{ type: 'ERROR' }], actions: [{ type: 'ACTION' }] };
+
+      testAction(asyncAction, null, {}, assertion.mutations, assertion.actions)
+        .then(done.fail)
+        .catch(error => {
+          originalExpect(error).toBe(lastError);
+          done();
+        });
+    });
+  });
+
+  it('works with async actions not returning promises', done => {
+    const data = { FOO: 'BAR' };
+
+    const asyncAction = ({ commit, dispatch }) => {
+      dispatch('ACTION');
+
+      axios
+        .get(TEST_HOST)
+        .then(() => {
+          commit('SUCCESS');
+          return data;
+        })
+        .catch(error => {
+          commit('ERROR');
+          throw error;
+        });
+    };
+
+    mock.onGet(TEST_HOST).replyOnce(200, 42);
+
+    assertion = { mutations: [{ type: 'SUCCESS' }], actions: [{ type: 'ACTION' }] };
+
+    testAction(asyncAction, null, {}, assertion.mutations, assertion.actions, done);
+  });
+});