chore: configure jest

Author: jerelmiller

__mocks__/file-mock.js

@@ -0,0 +1 @@
+module.exports = 'test-file-stub';

__mocks__/react-dom.js

@@ -0,0 +1,4 @@
+module.exports = {
+  ...jest.requireActual('react-dom'),
+  createPortal: (element) => element,
+};

jest-preprocess.js

@@ -0,0 +1,3 @@
+module.exports = require('babel-jest').createTransformer({
+  presets: ['babel-preset-gatsby', '@emotion/babel-preset-css-prop'],
+});

jest.config.js

@@ -0,0 +1,19 @@
+module.exports = {
+  transform: {
+    '^.+\\.jsx?$': '<rootDir>/jest-preprocess.js',
+  },
+  moduleNameMapper: {
+    '.+\\.(css|styl|less|sass|scss)$': 'identity-obj-proxy',
+    '.+\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
+      '<rootDir>/__mocks__/file-mock.js',
+  },
+  testPathIgnorePatterns: ['node_modules', '\\.cache', '<rootDir>.*/public'],
+  transformIgnorePatterns: [
+    'node_modules/(?!(gatsby)||@newrelic/gatsby-theme-newrelic||@elastic/react-search-ui-views/)',
+  ],
+  globals: {
+    __PATH_PREFIX__: '',
+  },
+  setupFiles: ['<rootDir>/loadershim.js'],
+  setupFilesAfterEnv: ['<rootDir>/setup-test-env.js'],
+};

loadershim.js

@@ -0,0 +1,3 @@
+global.___loader = {
+  enqueue: jest.fn(),
+};

setup-test-env.js

@@ -0,0 +1,5 @@
+/* global expect */
+import { createSerializer } from 'jest-emotion';
+import * as emotion from '@emotion/core';
+
+expect.addSnapshotSerializer(createSerializer(emotion));