Feat: unit tests for CohortsOverlapDiagram

src/Analysis/GWASV2/Components/Diagrams/CohortsOverlapDiagram/CohortsOverlapDiagram.jsx

@@ -160,7 +160,7 @@ const CohortsOverlapDiagram = ({
       statusStudyPopulationAndCaseAndControl,
     ].some((status) => status === 'loading')
   ) {
-    return <Spin />;
+    return <Spin data-testid='loading-spinner' />;
   }
   const eulerArgs = {
     set1Size: selectedStudyPopulationCohort.size,

src/Analysis/GWASV2/Components/Diagrams/CohortsOverlapDiagram/CohortsOverlapDiagram.test.jsx

@@ -0,0 +1,75 @@
+import React from 'react';
+import { screen, render } from '@testing-library/react';
+import '@testing-library/jest-dom/extend-expect';
+import { QueryClient, QueryClientProvider } from 'react-query';
+import CohortsOverlapDiagram from './CohortsOverlapDiagram';
+import ValidState from '../../../TestData/States/ValidState';
+import { SourceContextProvider } from '../../../Utils/Source';
+import {
+  fetchSimpleOverlapInfo,
+  useSourceFetch,
+} from '../../../Utils/cohortMiddlewareApi';
+
+// Mock relevant API calls:
+jest.mock('../../../Utils/cohortMiddlewareApi');
+fetchSimpleOverlapInfo.mockResolvedValue({
+  cohort_overlap: {
+    case_control_overlap: 123,
+  },
+});
+useSourceFetch.mockResolvedValue({
+  sourceId: 2, loading: false,
+});
+
+// Other generic arguments and functions shared by tests below:
+const mockedQueryClient = new QueryClient({
+  defaultOptions: {
+    queries: { retry: false },
+  },
+});
+
+// wrapper render method:
+const renderDiagram = (
+  selectedStudyPopulationCohort, dispatch) => render(
+  <QueryClientProvider client={mockedQueryClient}>
+    <SourceContextProvider>
+      <CohortsOverlapDiagram
+        dispatch={dispatch}
+        selectedStudyPopulationCohort={selectedStudyPopulationCohort}
+        selectedCaseCohort={selectedStudyPopulationCohort}
+        selectedControlCohort={selectedStudyPopulationCohort}
+        selectedCovariates={[]}
+        outcome={null}
+      />
+    </SourceContextProvider>
+  </QueryClientProvider>,
+);
+
+// Tests:
+describe('CohortsOverlapDiagram component', () => {
+  beforeEach(() => {
+    // workaround for issue https://github.com/jsdom/jsdom/issues/1664 / https://stackoverflow.com/questions/53725064/d3node-getcomputedtextlength-is-not-a-function:
+    window.SVGElement.prototype.getComputedTextLength = () => 12345;
+  });
+
+  afterEach(() => {
+    delete window.SVGElement.prototype.getComputedTextLength;
+  });
+
+  const flushPromises = () => new Promise(setImmediate);
+  const {
+    selectedStudyPopulationCohort,
+  } = ValidState;
+
+  it('should show a spinner and then, once data promises are resolved, it should render an Euler diagram', async () => {
+    renderDiagram(selectedStudyPopulationCohort, jest.fn());
+    // first thing that appears is a spinner, while web-service responses are pending:
+    expect(screen.getByTestId('loading-spinner')).toBeInTheDocument();
+    expect(screen.queryByTestId('euler-diagram')).toBeNull();
+    // flush the pending mock web-service responses:
+    await flushPromises();
+    // now we should expect to see the diagram, and the spinner to be gone:
+    expect(screen.getByTestId('euler-diagram')).toBeInTheDocument();
+    expect(screen.queryByTestId('loading-spinner')).toBeNull();
+  });
+});

src/Analysis/GWASV2/TestData/States/ValidState.js

@@ -6,7 +6,7 @@ const ValidState = {
   },
   selectedStudyPopulationCohort: {
     cohort_definition_id: 404,
-    cohort_name: 'Catch All (do not run generate)',
+    cohort_name: 'Mock study population cohort',
     size: 510904,
   },
   covariates: [