chore: add test framework (#42)

Part of #38 and #11

jest-preprocess.js

@@ -0,0 +1,5 @@
+const babelOptions = {
+  presets: ['babel-preset-gatsby'],
+};
+
+module.exports = require('babel-jest').default.createTransformer(babelOptions);

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)$': `<rootDir>/__mocks__/file-mock.js`,
+    '^gatsby-page-utils/(.*)$': `gatsby-page-utils/dist/$1`, // Workaround for https://github.com/facebook/jest/issues/9771
+  },
+  testPathIgnorePatterns: [`node_modules`, `\\.cache`, `<rootDir>.*/public`],
+  transformIgnorePatterns: [`node_modules/(?!(gatsby)/)`],
+  globals: {
+    __PATH_PREFIX__: ``,
+  },
+  testEnvironmentOptions: {
+    url: `http://localhost`,
+  },
+  setupFiles: [`<rootDir>/loadershim.js`],
+};

loadershim.js

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

package.json

@@ -5,13 +5,20 @@
     "demo"
   ],
   "scripts": {
+    "test": "jest --watch",
     "develop": "yarn workspace demo develop",
     "build": "yarn workspace demo build",
     "serve": "yarn workspace demo serve",
     "clean": "yarn workspace demo clean",
     "format": "prettier --write \".\""
   },
   "devDependencies": {
-    "prettier": "^2.6.2"
+    "babel-jest": "29.0.3",
+    "babel-preset-gatsby": "2.23.0",
+    "gatsby-plugin-utils": "3.17.1",
+    "identity-obj-proxy": "3.0.0",
+    "jest": "29.0.3",
+    "prettier": "^2.6.2",
+    "react-test-renderer": "18.2.0"
   }
 }

plugin/utils.test.js

@@ -0,0 +1,21 @@
+import { getResourceOptions } from './utils';
+
+describe('getResourceOptions', () => {
+  it('transforms options to snake case', () => {
+    const result = getResourceOptions({
+      resourceType: 'image',
+      prefix: 'demo/examples',
+      maxResults: 50,
+    });
+
+    const expected = {
+      resource_type: 'image',
+      prefix: 'demo/examples',
+      max_results: 50,
+      results_per_page: 50,
+      type: 'upload',
+    };
+
+    expect(result).toEqual(expected);
+  });
+});