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diff --git a/spec/frontend/analytics/usage_trends/components/users_chart_spec.js b/spec/frontend/analytics/usage_trends/components/users_chart_spec.js
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+++ b/spec/frontend/analytics/usage_trends/components/users_chart_spec.js
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+import { GlAlert } from '@gitlab/ui';
+import { GlAreaChart } from '@gitlab/ui/dist/charts';
+import { createLocalVue, shallowMount } from '@vue/test-utils';
+import VueApollo from 'vue-apollo';
+import createMockApollo from 'helpers/mock_apollo_helper';
+import UsersChart from '~/analytics/usage_trends/components/users_chart.vue';
+import usersQuery from '~/analytics/usage_trends/graphql/queries/users.query.graphql';
+import ChartSkeletonLoader from '~/vue_shared/components/resizable_chart/skeleton_loader.vue';
+import { mockQueryResponse } from '../apollo_mock_data';
+import {
+  mockCountsData1,
+  mockCountsData2,
+  roundedSortedCountsMonthlyChartData2,
+} from '../mock_data';
+
+const localVue = createLocalVue();
+localVue.use(VueApollo);
+
+describe('UsersChart', () => {
+  let wrapper;
+  let queryHandler;
+
+  const createComponent = ({
+    loadingError = false,
+    loading = false,
+    users = [],
+    additionalData = [],
+  } = {}) => {
+    queryHandler = mockQueryResponse({ key: 'users', data: users, loading, additionalData });
+
+    return shallowMount(UsersChart, {
+      props: {
+        startDate: new Date(2020, 9, 26),
+        endDate: new Date(2020, 10, 1),
+        totalDataPoints: mockCountsData2.length,
+      },
+      localVue,
+      apolloProvider: createMockApollo([[usersQuery, queryHandler]]),
+      data() {
+        return { loadingError };
+      },
+    });
+  };
+
+  afterEach(() => {
+    wrapper.destroy();
+    wrapper = null;
+  });
+
+  const findLoader = () => wrapper.find(ChartSkeletonLoader);
+  const findAlert = () => wrapper.find(GlAlert);
+  const findChart = () => wrapper.find(GlAreaChart);
+
+  describe('while loading', () => {
+    beforeEach(() => {
+      wrapper = createComponent({ loading: true });
+    });
+
+    it('displays the skeleton loader', () => {
+      expect(findLoader().exists()).toBe(true);
+    });
+
+    it('hides the chart', () => {
+      expect(findChart().exists()).toBe(false);
+    });
+  });
+
+  describe('without data', () => {
+    beforeEach(async () => {
+      wrapper = createComponent({ users: [] });
+      await wrapper.vm.$nextTick();
+    });
+
+    it('renders an no data message', () => {
+      expect(findAlert().text()).toBe('There is no data available.');
+    });
+
+    it('hides the skeleton loader', () => {
+      expect(findLoader().exists()).toBe(false);
+    });
+
+    it('renders the chart', () => {
+      expect(findChart().exists()).toBe(false);
+    });
+  });
+
+  describe('with data', () => {
+    beforeEach(async () => {
+      wrapper = createComponent({ users: mockCountsData2 });
+      await wrapper.vm.$nextTick();
+    });
+
+    it('hides the skeleton loader', () => {
+      expect(findLoader().exists()).toBe(false);
+    });
+
+    it('renders the chart', () => {
+      expect(findChart().exists()).toBe(true);
+    });
+
+    it('passes the data to the line chart', () => {
+      expect(findChart().props('data')).toEqual([
+        { data: roundedSortedCountsMonthlyChartData2, name: 'Total users' },
+      ]);
+    });
+  });
+
+  describe('with errors', () => {
+    beforeEach(async () => {
+      wrapper = createComponent({ loadingError: true });
+      await wrapper.vm.$nextTick();
+    });
+
+    it('renders an error message', () => {
+      expect(findAlert().text()).toBe(
+        'Could not load the user chart. Please refresh the page to try again.',
+      );
+    });
+
+    it('hides the skeleton loader', () => {
+      expect(findLoader().exists()).toBe(false);
+    });
+
+    it('renders the chart', () => {
+      expect(findChart().exists()).toBe(false);
+    });
+  });
+
+  describe('when fetching more data', () => {
+    describe('when the fetchMore query returns data', () => {
+      beforeEach(async () => {
+        wrapper = createComponent({
+          users: mockCountsData2,
+          additionalData: mockCountsData1,
+        });
+
+        jest.spyOn(wrapper.vm.$apollo.queries.users, 'fetchMore');
+        await wrapper.vm.$nextTick();
+      });
+
+      it('requests data twice', () => {
+        expect(queryHandler).toBeCalledTimes(2);
+      });
+
+      it('calls fetchMore', () => {
+        expect(wrapper.vm.$apollo.queries.users.fetchMore).toHaveBeenCalledTimes(1);
+      });
+    });
+
+    describe('when the fetchMore query throws an error', () => {
+      beforeEach(() => {
+        wrapper = createComponent({
+          users: mockCountsData2,
+          additionalData: mockCountsData1,
+        });
+
+        jest
+          .spyOn(wrapper.vm.$apollo.queries.users, 'fetchMore')
+          .mockImplementation(jest.fn().mockRejectedValue());
+        return wrapper.vm.$nextTick();
+      });
+
+      it('calls fetchMore', () => {
+        expect(wrapper.vm.$apollo.queries.users.fetchMore).toHaveBeenCalledTimes(1);
+      });
+
+      it('renders an error message', () => {
+        expect(findAlert().text()).toBe(
+          'Could not load the user chart. Please refresh the page to try again.',
+        );
+      });
+    });
+  });
+});