Undo this commit, it should still be worked on

This commit consists several commits:
1. added the const URL file which is used in GuitarGallery
2. Added a Loader to be presented while the component is still being rendered
3. Added tests for GuitarGallery

app/__mocks__/axios.js

@@ -0,0 +1,18 @@
+export default {
+  get: jest.fn().mockResolvedValue({
+    data: [
+      {
+        name: 'guitar1_test',
+        url: 'https://rukminim1.flixcart.com/image/416/416/acoustic-guitar/x/8/w/topaz-blue-signature-original-imaefec7uhypjdr9.jpeg?q=70',
+        price: '100',
+        description: 'some description in guitar1_test'
+      },
+      {
+        name: 'guitar2_test',
+        url: 'https://shop.brianmayguitars.co.uk/user/special/content/Antique%20Cherry%20a.jpg',
+        price: '200',
+        description: 'some description in guitar2_test'
+      }
+    ]
+  })
+};

app/controllers/guitars_controller.rb

@@ -1,24 +1,26 @@
+# frozen_string_literal: true
+
 class GuitarsController < ApplicationController
   def index
-    render :json => [
-        {
-            'name':'guitar1',
-            'url':'https://rukminim1.flixcart.com/image/416/416/acoustic-guitar/x/8/w/topaz-blue-signature-original-imaefec7uhypjdr9.jpeg?q=70',
-            'price':'100',
-            'description':'blablabla 1'
-        },
-        {
-            'name':'guitar2',
-            'url':'https://shop.brianmayguitars.co.uk/user/special/content/Antique%20Cherry%20a.jpg',
-            'price':'200',
-            'description':'blablabla 2'
-        },
-        {
-            'name':'guitar3',
-            'url':'https://cdn.mos.cms.futurecdn.net/Yh6r74b8CAj2jbdf2FAhq4-970-80.jpg.webp',
-            'price':'300',
-            'description':'blablabla 3'
-        }
+    render json: [
+      {
+        name: 'guitar1',
+        url: 'https://rukminim1.flixcart.com/image/416/416/acoustic-guitar/x/8/w/topaz-blue-signature-original-imaefec7uhypjdr9.jpeg?q=70',
+        price: '100',
+        description: 'blablabla 1'
+      },
+      {
+        name: 'guitar2',
+        url: 'https://shop.brianmayguitars.co.uk/user/special/content/Antique%20Cherry%20a.jpg',
+        price: '200',
+        description: 'blablabla 2'
+      },
+      {
+        name: 'guitar3',
+        url: 'https://cdn.mos.cms.futurecdn.net/Yh6r74b8CAj2jbdf2FAhq4-970-80.jpg.webp',
+        price: '300',
+        description: 'blablabla 3'
+      }
     ]
   end
 end

app/javascript/components/GuitarGallery.js

@@ -2,13 +2,18 @@ import React, { useEffect, useState } from 'react';
 import axios from 'axios';
 import { Title, TitleSizes, Gallery } from '@patternfly/react-core';
 import GuitarInfo from './GuitarInfo';
+import guitarsUrl from '../constUrls';
+import styled from 'styled-components';
+
+// is used in order to present a Loading 'screen' to the user until the data is rendered:
+const Loader = styled.div``;
 
 // Loading the data from the server:
 
 export const GuitarGallery = () => {
   const getGuitars = async () => {
     try {
-      const response = await axios.get('/guitars');
+      const response = await axios.get(guitarsUrl);
       if (response.data) {
         setGuitars(response.data);
       }
@@ -36,9 +41,13 @@ export const GuitarGallery = () => {
           xl: '200px',
           '2xl': '300px'
         }}>
-        {guitars.map(({ name, url, price, description }) => (
-          <GuitarInfo key={name} name={name} url={url} price={price} description={description} />
-        ))}
+        {guitars.length === 0 ? (
+          <Loader>Loading...</Loader>
+        ) : (
+          guitars.map(({ name, url, price, description }) => (
+            <GuitarInfo key={name} name={name} url={url} price={price} description={description} />
+          ))
+        )}
       </Gallery>
     </div>
   );

app/javascript/constUrls.js

@@ -0,0 +1 @@
+export const guitarsUrl = '/guitars';

jest.config.js

@@ -1,5 +1,204 @@
+/*
+ * For a detailed explanation regarding each configuration property, visit:
+ * https://jestjs.io/docs/configuration
+ */
 // eslint-disable-next-line no-undef
 module.exports = {
   setupFilesAfterEnv: ['./rtl.setup.js'],
-  testEnvironment: 'jsdom'
+  // All imported modules in your tests should be mocked automatically
+  // automock: false,
+
+  // Stop running tests after `n` failures
+  // bail: 0,
+
+  // The directory where Jest should store its cached dependency information
+  // cacheDirectory: "/tmp/jest_rs",
+
+  // Automatically clear mock calls, instances, contexts and results before every test
+  clearMocks: true,
+
+  // Indicates whether the coverage information should be collected while executing the test
+  // collectCoverage: false,
+
+  // An array of glob patterns indicating a set of files for which coverage information should be collected
+  // collectCoverageFrom: undefined,
+
+  // The directory where Jest should output its coverage files
+  // coverageDirectory: undefined,
+
+  // An array of regexp pattern strings used to skip coverage collection
+  // coveragePathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // Indicates which provider should be used to instrument code for coverage
+  // coverageProvider: "babel",
+
+  // A list of reporter names that Jest uses when writing coverage reports
+  // coverageReporters: [
+  //   "json",
+  //   "text",
+  //   "lcov",
+  //   "clover"
+  // ],
+
+  // An object that configures minimum threshold enforcement for coverage results
+  // coverageThreshold: undefined,
+
+  // A path to a custom dependency extractor
+  // dependencyExtractor: undefined,
+
+  // Make calling deprecated APIs throw helpful error messages
+  // errorOnDeprecated: false,
+
+  // The default configuration for fake timers
+  // fakeTimers: {
+  //   "enableGlobally": false
+  // },
+
+  // Force coverage collection from ignored files using an array of glob patterns
+  // forceCoverageMatch: [],
+
+  // A path to a module which exports an async function that is triggered once before all test suites
+  // globalSetup: undefined,
+
+  // A path to a module which exports an async function that is triggered once after all test suites
+  // globalTeardown: undefined,
+
+  // A set of global variables that need to be available in all test environments
+  // globals: {},
+
+  // The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
+  // maxWorkers: "50%",
+
+  // An array of directory names to be searched recursively up from the requiring module's location
+  // moduleDirectories: [
+  //   "node_modules"
+  // ],
+
+  // An array of file extensions your modules use
+  // moduleFileExtensions: [
+  //   "js",
+  //   "mjs",
+  //   "cjs",
+  //   "jsx",
+  //   "ts",
+  //   "tsx",
+  //   "json",
+  //   "node"
+  // ],
+
+  // A map from regular expressions to module names or to arrays of module names that allow to stub out resources with a single module
+  // moduleNameMapper: {},
+
+  // An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
+  // modulePathIgnorePatterns: [],
+
+  // Activates notifications for test results
+  // notify: false,
+
+  // An enum that specifies notification mode. Requires { notify: true }
+  // notifyMode: "failure-change",
+
+  // A preset that is used as a base for Jest's configuration
+  // preset: undefined,
+
+  // Run tests from one or more projects
+  // projects: undefined,
+
+  // Use this configuration option to add custom reporters to Jest
+  // reporters: undefined,
+
+  // Automatically reset mock state before every test
+  // resetMocks: false,
+
+  // Reset the module registry before running each individual test
+  // resetModules: false,
+
+  // A path to a custom resolver
+  // resolver: undefined,
+
+  // Automatically restore mock state and implementation before every test
+  // restoreMocks: false,
+
+  // The root directory that Jest should scan for tests and modules within
+  // rootDir: undefined,
+
+  // A list of paths to directories that Jest should use to search for files in
+  // roots: [
+  //   "<rootDir>"
+  // ],
+
+  // Allows you to use a custom runner instead of Jest's default test runner
+  // runner: "jest-runner",
+
+  // The paths to modules that run some code to configure or set up the testing environment before each test
+  // setupFiles: [],
+
+  // A list of paths to modules that run some code to configure or set up the testing framework before each test
+  // setupFilesAfterEnv: [],
+
+  // The number of seconds after which a test is considered as slow and reported as such in the results.
+  // slowTestThreshold: 5,
+
+  // A list of paths to snapshot serializer modules Jest should use for snapshot testing
+  // snapshotSerializers: [],
+
+  // The test environment that will be used for testing
+  testEnvironment: 'jsdom',
+
+  // Options that will be passed to the testEnvironment
+  // testEnvironmentOptions: {},
+
+  // Adds a location field to test results
+  // testLocationInResults: false,
+
+  // The glob patterns Jest uses to detect test files
+  // testMatch: [
+  //   "**/__tests__/**/*.[jt]s?(x)",
+  //   "**/?(*.)+(spec|test).[tj]s?(x)"
+  // ],
+
+  // An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
+  // testPathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // The regexp pattern or array of patterns that Jest uses to detect test files
+  // testRegex: [],
+
+  // This option allows the use of a custom results processor
+  // testResultsProcessor: undefined,
+
+  // This option allows use of a custom test runner
+  // testRunner: "jest-circus/runner",
+
+  // A map from regular expressions to paths to transformers
+  // transform: undefined,
+
+  // An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
+  // transformIgnorePatterns: ['/node_modules/', '\\.pnp\\.[^\\/]+$']
+
+  transformIgnorePatterns: [
+    'node_modules/(?!(react-native' +
+      '|react-navigation-tabs' +
+      '|react-native-splash-screen' +
+      '|react-native-screens' +
+      '|react-native-reanimated' +
+      ')/)',
+    'node_modules/(?!(jest-)?react-native|react-(native|universal|navigation)-(.*)|@react-native-community/(.*)|@react-navigation/(.*)|bs-platform|(@[a-zA-Z]+/)?(bs|reason|rescript)-(.*)+)',
+    '/node_modules/'
+  ]
+
+  // An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
+  // unmockedModulePathPatterns: undefined,
+
+  // Indicates whether each individual test should be reported during the run
+  // verbose: undefined,
+
+  // An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
+  // watchPathIgnorePatterns: [],
+
+  // Whether to use watchman for file crawling
+  // watchman: true,
 };

test/controllers/guitars_controller_test.rb

@@ -3,7 +3,7 @@
 require 'test_helper'
 
 class GuitarsControllerTest < ActionDispatch::IntegrationTest
-  test "should get index" do
+  test 'get index' do
     get guitars_index_url
     assert_response :success
   end

test/javascript/GuitarGallery.test.js

@@ -0,0 +1,52 @@
+import React from 'react';
+import { render, screen /*, waitForElement*/ } from '@testing-library/react';
+import '@testing-library/jest-dom/extend-expect';
+import axios from 'axios';
+import GuitarGallery from '../../app/javascript/components/GuitarGallery';
+import guitarsUrl from '../../javascript/constUrls';
+
+test("show loader when it's fetching data, then render Guitars", async () => {
+  axios.get.mockResolvedValueOnce({
+    data: [
+      {
+        name: 'guitar1_test',
+        url: 'https://rukminim1.flixcart.com/image/416/416/acoustic-guitar/x/8/w/topaz-blue-signature-original-imaefec7uhypjdr9.jpeg?q=70',
+        price: '100',
+        description: 'some description in guitar1_test'
+      },
+      {
+        name: 'guitar2_test',
+        url: 'https://shop.brianmayguitars.co.uk/user/special/content/Antique%20Cherry%20a.jpg',
+        price: '200',
+        description: 'some description in guitar2_test'
+      }
+    ]
+  });
+
+  //show loader
+  const { unmount, /*getAllByTestId,*/ getByText } = render(<GuitarGallery />);
+  expect(getByText(/loading.../i)).toBeInTheDocument();
+
+  // check the correct url is called:
+  expect(axios.get).toHaveBeenCalledWith(guitarsUrl);
+  expect(axios.get).toHaveBeenCalledTimes(1);
+
+  //   //check what's rendered in the row
+  //  const rowValues = await waitForElement(() => getAllByTestId('row').map((row) => row.textContent));
+  //  expect(rowValues).toEqual(['ali', 'abu']);
+
+  const guitarDescriptions = screen.findAllBy('Description');
+  const expectedDescription = [
+    'some description in guitar1_test',
+    'some description in guitar2_test'
+  ];
+  // option 1:
+  expect(guitarDescriptions).toEqual(expectedDescription);
+  // option 2:
+  guitarDescriptions.forEach((description, index) => {
+    expect(description).toBe(expectedDescription.at(index));
+  });
+
+  // unmnount the component from the DOM
+  unmount();
+});