Mock Circos component in tests

A recent change has made it so that Circos graphs are rendered
by default. This has syrfaced an issue that d3 is not set up in
the test suite with jsdom properly and was erring. The tests do
not require Circos graphs to render, so we can mock the component
fully.
R

Author: tadast

jest.config.js

@@ -41,6 +41,7 @@ module.exports = {
         'download_links': '<rootDir>/public/js/null_plugins/download_links.js',
         'hit_buttons': '<rootDir>/public/js/null_plugins/hit_buttons.js',
         'search_header_plugin': '<rootDir>/public/js/null_plugins/search_header_plugin.js',
+        'circos$': '<rootDir>/public/js/tests/mocks/circos.js',
     },
     watchPlugins: [
         'jest-watch-typeahead/filename',

public/js/tests/mocks/circos.js

@@ -0,0 +1,6 @@
+const Circos = () => {
+    // console.log("Circos mock loaded");
+    return <div></div>;
+};
+
+export default Circos;

public/js/tests/report.spec.js

@@ -5,7 +5,6 @@ import Report from '../report';
 import Sidebar from '../sidebar';
 import shortResponseJSON from './mock_data/short_response.json';
 import longResponseJSON from './mock_data/long_response.json';
-import d3 from 'd3';
 
 const setMockJSONResult = (result) => {
     global.$.getJSON = () => ({ complete: jest.fn((callback) => callback(result)) });
@@ -45,6 +44,7 @@ describe('REPORT PAGE', () => {
         render(<Report showErrorModal={showErrorModal} />);
         expect(showErrorModal).toHaveBeenCalledTimes(1);
     });
+
     it('it should render the report page correctly if there\'s a response provided', () => {
         setMockJSONResult({ status: 200, responseJSON: shortResponseJSON });
         const { container } = render(<Report getCharacterWidth={jest.fn()} />);