Feat(Instance Analytics): add pipelines chart

Add pipelines chart, so the user can see the
development in numbers of failed, succeeded,
cancelled, skipped, and total pipelines accross
the instance.

app/assets/javascripts/analytics/instance_statistics/components/app.vue

 <script>
 import InstanceCounts from './instance_counts.vue';
+import PipelinesChart from './pipelines_chart.vue';
 
 export default {
   name: 'InstanceStatisticsApp',
   components: {
     InstanceCounts,
+    PipelinesChart,
   },
 };
 </script>
 
 <template>
-  <instance-counts />
+  <div>
+    <instance-counts />
+    <pipelines-chart />
+  </div>
 </template>

app/assets/javascripts/analytics/instance_statistics/components/pipelines_chart.vue

+<script>
+import { GlLineChart } from '@gitlab/ui/dist/charts';
+import { GlAlert } from '@gitlab/ui';
+import { mapKeys, mapValues, pick, some, sum } from 'lodash';
+import ChartSkeletonLoader from '~/vue_shared/components/resizable_chart/skeleton_loader.vue';
+import { s__ } from '~/locale';
+import { formatDateAsMonth, getDayDifference } from '~/lib/utils/datetime_utility';
+import { getAverageByMonth, sortByDate, extractValues } from '../utils';
+import pipelineStatsQuery from '../graphql/queries/pipeline_stats.query.graphql';
+import { TODAY, START_DATE } from '../constants';
+
+const DATA_KEYS = [
+  'pipelinesTotal',
+  'pipelinesSucceeded',
+  'pipelinesFailed',
+  'pipelinesCanceled',
+  'pipelinesSkipped',
+];
+const PREFIX = 'pipelines';
+
+export default {
+  name: 'PipelinesChart',
+  components: {
+    GlLineChart,
+    GlAlert,
+    ChartSkeletonLoader,
+  },
+  startDate: START_DATE,
+  endDate: TODAY,
+  i18n: {
+    loadPipelineChartError: s__(
+      'InstanceAnalytics|Could not load the pipelines chart. Please refresh the page to try again.',
+    ),
+    noDataMessage: s__('InstanceAnalytics|There is no data available.'),
+    total: s__('InstanceAnalytics|Total'),
+    succeeded: s__('InstanceAnalytics|Succeeded'),
+    failed: s__('InstanceAnalytics|Failed'),
+    canceled: s__('InstanceAnalytics|Canceled'),
+    skipped: s__('InstanceAnalytics|Skipped'),
+    chartTitle: s__('InstanceAnalytics|Pipelines'),
+    yAxisTitle: s__('InstanceAnalytics|Items'),
+    xAxisTitle: s__('InstanceAnalytics|Month'),
+  },
+  data() {
+    return {
+      loading: true,
+      loadingError: null,
+    };
+  },
+  apollo: {
+    pipelineStats: {
+      query: pipelineStatsQuery,
+      variables() {
+        return {
+          firstTotal: this.totalDaysToShow,
+          firstSucceeded: this.totalDaysToShow,
+          firstFailed: this.totalDaysToShow,
+          firstCanceled: this.totalDaysToShow,
+          firstSkipped: this.totalDaysToShow,
+        };
+      },
+      update(data) {
+        const allData = extractValues(data, DATA_KEYS, PREFIX, 'nodes');
+        const allPageInfo = extractValues(data, DATA_KEYS, PREFIX, 'pageInfo');
+
+        return {
+          ...mapValues(allData, sortByDate),
+          ...allPageInfo,
+        };
+      },
+      result() {
+        if (this.hasNextPage) {
+          this.fetchNextPage();
+        }
+      },
+      error() {
+        this.handleError();
+      },
+    },
+  },
+  computed: {
+    isLoading() {
+      return this.$apollo.queries.pipelineStats.loading;
+    },
+    totalDaysToShow() {
+      return getDayDifference(this.$options.startDate, this.$options.endDate);
+    },
+    firstVariables() {
+      const allData = pick(this.pipelineStats, [
+        'nodesTotal',
+        'nodesSucceeded',
+        'nodesFailed',
+        'nodesCanceled',
+        'nodesSkipped',
+      ]);
+      const allDayDiffs = mapValues(allData, data => {
+        const firstdataPoint = data[0];
+        if (!firstdataPoint) {
+          return 0;
+        }
+
+        return Math.max(
+          0,
+          getDayDifference(this.$options.startDate, new Date(firstdataPoint.recordedAt)),
+        );
+      });
+
+      return mapKeys(allDayDiffs, (value, key) => key.replace('nodes', 'first'));
+    },
+    cursorVariables() {
+      const pageInfoKeys = [
+        'pageInfoTotal',
+        'pageInfoSucceeded',
+        'pageInfoFailed',
+        'pageInfoCanceled',
+        'pageInfoSkipped',
+      ];
+
+      return extractValues(this.pipelineStats, pageInfoKeys, 'pageInfo', 'endCursor');
+    },
+    hasNextPage() {
+      return (
+        sum(Object.values(this.firstVariables)) > 0 &&
+        some(this.pipelineStats, ({ hasNextPage }) => hasNextPage)
+      );
+    },
+    hasEmptyDataSet() {
+      return this.chartData.every(({ data }) => data.length === 0);
+    },
+    chartData() {
+      const allData = pick(this.pipelineStats, [
+        'nodesTotal',
+        'nodesSucceeded',
+        'nodesFailed',
+        'nodesCanceled',
+        'nodesSkipped',
+      ]);
+      const options = { shouldRound: true };
+      return Object.keys(allData).map(key => {
+        const i18nName = key.slice('nodes'.length).toLowerCase();
+        return {
+          name: this.$options.i18n[i18nName],
+          data: getAverageByMonth(allData[key], options),
+        };
+      });
+    },
+    range() {
+      return {
+        min: this.$options.startDate,
+        max: this.$options.endDate,
+      };
+    },
+    differenceInMonths() {
+      const yearDiff = this.$options.endDate.getYear() - this.$options.startDate.getYear();
+      const monthDiff = this.$options.endDate.getMonth() - this.$options.startDate.getMonth();
+
+      return monthDiff + 12 * yearDiff;
+    },
+    chartOptions() {
+      return {
+        xAxis: {
+          ...this.range,
+          name: this.$options.i18n.xAxisTitle,
+          type: 'time',
+          splitNumber: this.differenceInMonths + 1,
+          axisLabel: {
+            interval: 0,
+            showMinLabel: false,
+            showMaxLabel: false,
+            align: 'right',
+            formatter: formatDateAsMonth,
+          },
+        },
+        yAxis: {
+          name: this.$options.i18n.yAxisTitle,
+        },
+      };
+    },
+  },
+  methods: {
+    handleError() {
+      this.loadingError = true;
+    },
+    fetchNextPage() {
+      this.$apollo.queries.pipelineStats
+        .fetchMore({
+          variables: {
+            ...this.firstVariables,
+            ...this.cursorVariables,
+          },
+          updateQuery: (previousResult, { fetchMoreResult }) => {
+            return Object.keys(fetchMoreResult).reduce((memo, key) => {
+              const { nodes, ...rest } = fetchMoreResult[key];
+              const previousNodes = previousResult[key].nodes;
+              return { ...memo, [key]: { ...rest, nodes: [...previousNodes, ...nodes] } };
+            }, {});
+          },
+        })
+        .catch(this.handleError);
+    },
+  },
+};
+</script>
+<template>
+  <div>
+    <h3>{{ $options.i18n.chartTitle }}</h3>
+    <gl-alert v-if="loadingError" variant="danger" :dismissible="false" class="gl-mt-3">
+      {{ this.$options.i18n.loadPipelineChartError }}
+    </gl-alert>
+    <chart-skeleton-loader v-else-if="isLoading" />
+    <gl-alert v-else-if="hasEmptyDataSet" variant="info" :dismissible="false" class="gl-mt-3">
+      {{ $options.i18n.noDataMessage }}
+    </gl-alert>
+    <gl-line-chart v-else :option="chartOptions" :include-legend-avg-max="true" :data="chartData" />
+  </div>
+</template>

app/assets/javascripts/analytics/instance_statistics/constants.js

+import { getDateInPast } from '~/lib/utils/datetime_utility';
+
+const TOTAL_DAYS_TO_SHOW = 365;
+export const TODAY = new Date();
+export const START_DATE = getDateInPast(TODAY, TOTAL_DAYS_TO_SHOW);

app/assets/javascripts/analytics/instance_statistics/graphql/queries/count.fragment.graphql

+fragment Count on InstanceStatisticsMeasurement {
+  count
+  recordedAt
+}

app/assets/javascripts/analytics/instance_statistics/graphql/queries/pipeline_stats.query.graphql

+#import "~/graphql_shared/fragments/pageInfo.fragment.graphql"
+#import "./count.fragment.graphql"
+
+query pipelineStats(
+  $firstTotal: Int
+  $firstSucceeded: Int
+  $firstFailed: Int
+  $firstCanceled: Int
+  $firstSkipped: Int
+  $endCursorTotal: String
+  $endCursorSucceeded: String
+  $endCursorFailed: String
+  $endCursorCanceled: String
+  $endCursorSkipped: String
+) {
+  pipelinesTotal: instanceStatisticsMeasurements(
+    identifier: PIPELINES
+    first: $firstTotal
+    after: $endCursorTotal
+  ) {
+    nodes {
+      ...Count
+    }
+    pageInfo {
+      ...PageInfo
+    }
+  }
+  pipelinesSucceeded: instanceStatisticsMeasurements(
+    identifier: PIPELINES_SUCCEEDED
+    first: $firstSucceeded
+    after: $endCursorSucceeded
+  ) {
+    nodes {
+      ...Count
+    }
+    pageInfo {
+      ...PageInfo
+    }
+  }
+  pipelinesFailed: instanceStatisticsMeasurements(
+    identifier: PIPELINES_FAILED
+    first: $firstFailed
+    after: $endCursorFailed
+  ) {
+    nodes {
+      ...Count
+    }
+    pageInfo {
+      ...PageInfo
+    }
+  }
+  pipelinesCanceled: instanceStatisticsMeasurements(
+    identifier: PIPELINES_CANCELED
+    first: $firstCanceled
+    after: $endCursorCanceled
+  ) {
+    nodes {
+      ...Count
+    }
+    pageInfo {
+      ...PageInfo
+    }
+  }
+  pipelinesSkipped: instanceStatisticsMeasurements(
+    identifier: PIPELINES_SKIPPED
+    first: $firstSkipped
+    after: $endCursorSkipped
+  ) {
+    nodes {
+      ...Count
+    }
+    pageInfo {
+      ...PageInfo
+    }
+  }
+}

app/assets/javascripts/analytics/instance_statistics/utils.js

 import { masks } from 'dateformat';
+import { mapKeys, mapValues, pick, sortBy } from 'lodash';
 import { formatDate } from '~/lib/utils/datetime_utility';
 
 const { isoDate } = masks;
@@ -38,3 +39,31 @@ export function getAverageByMonth(items = [], options = {}) {
     return [month, avg];
   });
 }
+
+/**
+ * Extracts values given a data set and a set of keys
+ * @example
+ * const data = { fooBar: { baz: 'quis' }, ignored: 'ignored' };
+ * extractValues(data, ['fooBar'], 'foo', 'baz') => { bazBar: 'quis' }
+ * @param  {Object} data set to extract values from
+ * @param  {Array}  dataKeys keys describing where to look for values in the data set
+ * @param  {String} replaceKey name key to be replaced in the data set
+ * @param  {String} nestedKey key nested in the data set to be extracted,
+ *                  this is also used to rename the newly created data set
+ * @return {Object} the newly created data set with the extracted values
+ */
+export function extractValues(data, dataKeys = [], replaceKey, nestedKey) {
+  return mapKeys(pick(mapValues(data, nestedKey), dataKeys), (value, key) =>
+    key.replace(replaceKey, nestedKey),
+  );
+}
+
+/**
+ * Creates a new array of items sorted by the date string of each item
+ * @param  {Array} items [description]
+ * @param  {String} items[0] date string
+ * @return {Array} the new sorted array.
+ */
+export function sortByDate(items = []) {
+  return sortBy(items, ({ recordedAt }) => new Date(recordedAt).getTime());
+}

locale/gitlab.pot

@@ -14095,6 +14095,36 @@ msgstr ""
 msgid "Instance administrators group already exists"
 msgstr ""
 
+msgid "InstanceAnalytics|Canceled"
+msgstr ""
+
+msgid "InstanceAnalytics|Could not load the pipelines chart. Please refresh the page to try again."
+msgstr ""
+
+msgid "InstanceAnalytics|Failed"
+msgstr ""
+
+msgid "InstanceAnalytics|Items"
+msgstr ""
+
+msgid "InstanceAnalytics|Month"
+msgstr ""
+
+msgid "InstanceAnalytics|Pipelines"
+msgstr ""
+
+msgid "InstanceAnalytics|Skipped"
+msgstr ""
+
+msgid "InstanceAnalytics|Succeeded"
+msgstr ""
+
+msgid "InstanceAnalytics|There is no data available."
+msgstr ""
+
+msgid "InstanceAnalytics|Total"
+msgstr ""
+
 msgid "InstanceStatistics|Groups"
 msgstr ""
 

spec/frontend/analytics/instance_statistics/apollo_mock_data.js

+const defaultPageInfo = { hasPreviousPage: false, startCursor: null, endCursor: null };
+
+export function getApolloResponse(options = {}) {
+  const {
+    pipelinesTotal = [],
+    pipelinesSucceeded = [],
+    pipelinesFailed = [],
+    pipelinesCanceled = [],
+    pipelinesSkipped = [],
+    hasNextPage = false,
+  } = options;
+  return {
+    data: {
+      pipelinesTotal: { pageInfo: { ...defaultPageInfo, hasNextPage }, nodes: pipelinesTotal },
+      pipelinesSucceeded: {
+        pageInfo: { ...defaultPageInfo, hasNextPage },
+        nodes: pipelinesSucceeded,
+      },
+      pipelinesFailed: { pageInfo: { ...defaultPageInfo, hasNextPage }, nodes: pipelinesFailed },
+      pipelinesCanceled: {
+        pageInfo: { ...defaultPageInfo, hasNextPage },
+        nodes: pipelinesCanceled,
+      },
+      pipelinesSkipped: {
+        pageInfo: { ...defaultPageInfo, hasNextPage },
+        nodes: pipelinesSkipped,
+      },
+    },
+  };
+}

spec/frontend/analytics/instance_statistics/components/__snapshots__/pipelines_chart_spec.js.snap

+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`PipelinesChart when fetching more data when the fetchMore query returns data passes the data to the line chart 1`] = `
+Array [
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        21,
+      ],
+      Array [
+        "2020-07-01",
+        10,
+      ],
+      Array [
+        "2020-08-01",
+        5,
+      ],
+    ],
+    "name": "Total",
+  },
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        21,
+      ],
+      Array [
+        "2020-07-01",
+        10,
+      ],
+      Array [
+        "2020-08-01",
+        5,
+      ],
+    ],
+    "name": "Succeeded",
+  },
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        22,
+      ],
+      Array [
+        "2020-07-01",
+        41,
+      ],
+      Array [
+        "2020-08-01",
+        5,
+      ],
+    ],
+    "name": "Failed",
+  },
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        21,
+      ],
+      Array [
+        "2020-07-01",
+        10,
+      ],
+      Array [
+        "2020-08-01",
+        5,
+      ],
+    ],
+    "name": "Canceled",
+  },
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        21,
+      ],
+      Array [
+        "2020-07-01",
+        10,
+      ],
+      Array [
+        "2020-08-01",
+        5,
+      ],
+    ],
+    "name": "Skipped",
+  },
+]
+`;
+
+exports[`PipelinesChart with data passes the data to the line chart 1`] = `
+Array [
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        22,
+      ],
+      Array [
+        "2020-07-01",
+        41,
+      ],
+    ],
+    "name": "Total",
+  },
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        21,
+      ],
+      Array [
+        "2020-07-01",
+        10,
+      ],
+    ],
+    "name": "Succeeded",
+  },
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        21,
+      ],
+      Array [
+        "2020-07-01",
+        10,
+      ],
+    ],
+    "name": "Failed",
+  },
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        22,
+      ],
+      Array [
+        "2020-07-01",
+        41,
+      ],
+    ],
+    "name": "Canceled",
+  },
+  Object {
+    "data": Array [
+      Array [
+        "2020-06-01",
+        22,
+      ],
+      Array [
+        "2020-07-01",
+        41,
+      ],
+    ],
+    "name": "Skipped",
+  },
+]
+`;

spec/frontend/analytics/instance_statistics/components/app_spec.js

 import { shallowMount } from '@vue/test-utils';
 import InstanceStatisticsApp from '~/analytics/instance_statistics/components/app.vue';
 import InstanceCounts from '~/analytics/instance_statistics/components//instance_counts.vue';
+import PipelinesChart from '~/analytics/instance_statistics/components/pipelines_chart.vue';
 
 describe('InstanceStatisticsApp', () => {
   let wrapper;
@@ -21,4 +22,8 @@ describe('InstanceStatisticsApp', () => {
   it('displays the instance counts component', () => {
     expect(wrapper.find(InstanceCounts).exists()).toBe(true);
   });
+
+  it('displays the pipelines chart component', () => {
+    expect(wrapper.find(PipelinesChart).exists()).toBe(true);
+  });
 });

spec/frontend/analytics/instance_statistics/components/pipelines_chart_spec.js

+import { createLocalVue, shallowMount } from '@vue/test-utils';
+import { GlLineChart } from '@gitlab/ui/dist/charts';
+import { GlAlert } from '@gitlab/ui';
+import VueApollo from 'vue-apollo';
+import createMockApollo from 'jest/helpers/mock_apollo_helper';
+import PipelinesChart from '~/analytics/instance_statistics/components/pipelines_chart.vue';
+import pipelinesStatsQuery from '~/analytics/instance_statistics/graphql/queries/pipeline_stats.query.graphql';
+import ChartSkeletonLoader from '~/vue_shared/components/resizable_chart/skeleton_loader.vue';
+import { mockCountsData1, mockCountsData2 } from '../mock_data';
+import { getApolloResponse } from '../apollo_mock_data';
+
+const localVue = createLocalVue();
+localVue.use(VueApollo);
+
+describe('PipelinesChart', () => {
+  let wrapper;
+  let queryHandler;
+
+  const createApolloProvider = pipelineStatsHandler => {
+    return createMockApollo([[pipelinesStatsQuery, pipelineStatsHandler]]);
+  };
+
+  const createComponent = apolloProvider => {
+    return shallowMount(PipelinesChart, {
+      localVue,
+      apolloProvider,
+    });
+  };
+
+  afterEach(() => {
+    wrapper.destroy();
+    wrapper = null;
+  });
+
+  const findLoader = () => wrapper.find(ChartSkeletonLoader);
+  const findChart = () => wrapper.find(GlLineChart);
+  const findAlert = () => wrapper.find(GlAlert);
+
+  describe('while loading', () => {
+    beforeEach(() => {
+      queryHandler = jest.fn().mockReturnValue(new Promise(() => {}));
+      const apolloProvider = createApolloProvider(queryHandler);
+      wrapper = createComponent(apolloProvider);
+    });
+
+    it('requests data', () => {
+      expect(queryHandler).toBeCalledTimes(1);
+    });
+
+    it('displays the skeleton loader', () => {
+      expect(findLoader().exists()).toBe(true);
+    });
+
+    it('hides the chart', () => {
+      expect(findChart().exists()).toBe(false);
+    });
+
+    it('does not show an error', () => {
+      expect(findAlert().exists()).toBe(false);
+    });
+  });
+
+  describe('without data', () => {
+    beforeEach(() => {
+      const emptyResponse = getApolloResponse();
+      queryHandler = jest.fn().mockResolvedValue(emptyResponse);
+      const apolloProvider = createApolloProvider(queryHandler);
+      wrapper = createComponent(apolloProvider);
+    });
+
+    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(() => {
+      const response = getApolloResponse({
+        pipelinesTotal: mockCountsData1,
+        pipelinesSucceeded: mockCountsData2,
+        pipelinesFailed: mockCountsData2,
+        pipelinesCanceled: mockCountsData1,
+        pipelinesSkipped: mockCountsData1,
+      });
+      queryHandler = jest.fn().mockResolvedValue(response);
+      const apolloProvider = createApolloProvider(queryHandler);
+      wrapper = createComponent(apolloProvider);
+    });
+
+    it('requests data', () => {
+      expect(queryHandler).toBeCalledTimes(1);
+    });
+
+    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')).toMatchSnapshot();
+    });
+
+    it('does not show an error', () => {
+      expect(findAlert().exists()).toBe(false);
+    });
+  });
+
+  describe('when fetching more data', () => {
+    const recordedAt = '2020-08-01';
+    describe('when the fetchMore query returns data', () => {
+      beforeEach(async () => {
+        const newData = { recordedAt, count: 5 };
+        const firstResponse = getApolloResponse({
+          pipelinesTotal: mockCountsData2,
+          pipelinesSucceeded: mockCountsData2,
+          pipelinesFailed: mockCountsData1,
+          pipelinesCanceled: mockCountsData2,
+          pipelinesSkipped: mockCountsData2,
+          hasNextPage: true,
+        });
+        const secondResponse = getApolloResponse({
+          pipelinesTotal: [newData],
+          pipelinesSucceeded: [newData],
+          pipelinesFailed: [newData],
+          pipelinesCanceled: [newData],
+          pipelinesSkipped: [newData],
+          hasNextPage: false,
+        });
+        queryHandler = jest
+          .fn()
+          .mockResolvedValueOnce(firstResponse)
+          .mockResolvedValueOnce(secondResponse);
+        const apolloProvider = createApolloProvider(queryHandler);
+        wrapper = createComponent(apolloProvider);
+
+        await wrapper.vm.$nextTick();
+      });
+
+      it('requests data twice', () => {
+        expect(queryHandler).toBeCalledTimes(2);
+      });
+
+      it('passes the data to the line chart', () => {
+        expect(findChart().props('data')).toMatchSnapshot();
+      });
+    });
+
+    describe('when the fetchMore query throws an error', () => {
+      beforeEach(async () => {
+        const response = getApolloResponse({
+          pipelinesTotal: mockCountsData2,
+          pipelinesSucceeded: mockCountsData2,
+          pipelinesFailed: mockCountsData1,
+          pipelinesCanceled: mockCountsData2,
+          pipelinesSkipped: mockCountsData2,
+          hasNextPage: true,
+        });
+        queryHandler = jest.fn().mockResolvedValue(response);
+        const apolloProvider = createApolloProvider(queryHandler);
+        wrapper = createComponent(apolloProvider);
+        jest
+          .spyOn(wrapper.vm.$apollo.queries.pipelineStats, 'fetchMore')
+          .mockImplementation(jest.fn().mockRejectedValue());
+        await wrapper.vm.$nextTick();
+      });
+
+      it('calls fetchMore', () => {
+        expect(wrapper.vm.$apollo.queries.pipelineStats.fetchMore).toHaveBeenCalledTimes(1);
+      });
+
+      it('show an error message', () => {
+        expect(findAlert().text()).toBe(
+          'Could not load the pipelines chart. Please refresh the page to try again.',
+        );
+      });
+    });
+  });
+});

spec/frontend/analytics/instance_statistics/utils_spec.js

-import { getAverageByMonth } from '~/analytics/instance_statistics/utils';
+import {
+  getAverageByMonth,
+  extractValues,
+  sortByDate,
+} from '~/analytics/instance_statistics/utils';
 import {
   mockCountsData1,
   mockCountsData2,
@@ -39,3 +43,42 @@ describe('getAverageByMonth', () => {
     });
   });
 });
+
+describe('extractValues', () => {
+  it('extracts only requested values', () => {
+    const data = { fooBar: { baz: 'quis' }, ignored: 'ignored' };
+    expect(extractValues(data, ['fooBar'], 'foo', 'baz')).toEqual({ bazBar: 'quis' });
+  });
+
+  it('is able to extract multiple values', () => {
+    const data = {
+      fooBar: { baz: 'quis' },
+      fooBaz: { baz: 'quis' },
+      fooQuis: { baz: 'quis' },
+    };
+    expect(extractValues(data, ['fooBar', 'fooBaz', 'fooQuis'], 'foo', 'baz')).toEqual({
+      bazBar: 'quis',
+      bazBaz: 'quis',
+      bazQuis: 'quis',
+    });
+  });
+
+  it('returns empty data set when keys are not found', () => {
+    const data = { foo: { baz: 'quis' }, ignored: 'ignored' };
+    expect(extractValues(data, ['fooBar'], 'foo', 'baz')).toEqual({});
+  });
+
+  it('returns empty data when params are missing', () => {
+    expect(extractValues()).toEqual({});
+  });
+});
+
+describe('sortByDate', () => {
+  it('sorts the array by date', () => {
+    expect(sortByDate(mockCountsData1)).toStrictEqual([...mockCountsData1].reverse());
+  });
+
+  it('does not modify the original array', () => {
+    expect(sortByDate(countsMonthlyChartData1)).not.toBe(countsMonthlyChartData1);
+  });
+});