test(demo): test waiter and file-access

Author: nivekcode

__mocks__/chalk.js

@@ -0,0 +1,10 @@
+'use strict';
+const chalk = jest.genMockFromModule('chalk');
+
+chalk.red = jest.fn();
+chalk.green = jest.fn();
+chalk.blue = {
+    bold: jest.fn()
+};
+
+module.exports = chalk;

__mocks__/jsonfile.js

@@ -1,25 +1,14 @@
 'use strict';
 const jsonfile = jest.genMockFromModule('jsonfile');
 
-let mockedReadFileResponse;
-let throwError = false;
+let throwError;
 
-const setup = (responseMock, errorResponse) => {
-    if (errorResponse) {
-        throwError = true;
-    }
-    mockedReadFileResponse = responseMock;
-};
-const readFileSync = jest.fn(() => {
-    if (throwError) {
-        throw 'Something went wrong';
-    }
-    return mockedReadFileResponse;
-});
-const writeFileSync = jest.fn((path, file) => {});
+const setup = withError => (throwError = withError);
 
+const writeFile = jest.fn((fileName, order, cb) => {
+    throwError ? cb('Something went wrong') : cb();
+});
 jsonfile.setup = setup;
-jsonfile.readFileSync = readFileSync;
-jsonfile.writeFileSync = writeFileSync;
+jsonfile.writeFile = writeFile;
 
 module.exports = jsonfile;

src/file-access.js

@@ -3,11 +3,9 @@ const jsonfile = require('jsonfile');
 
 function writeFile(fileName, order) {
     jsonfile.writeFile(fileName, order, function(err) {
-        if (err) {
-            console.log(chalk.red(err));
-        } else {
-            console.log(chalk.green(`Success`));
-        }
+        err
+            ? console.log(chalk.red(err))
+            : console.log(chalk.green('Order successfully written to file'));
     });
 }
 

src/file-access.spec.js

@@ -0,0 +1,25 @@
+const jsonfile = require('jsonfile');
+const chalk = require('chalk');
+
+const sut = require('./file-access');
+
+describe('file access', () => {
+    beforeAll(() => (console.log = jest.fn()));
+
+    test('should log an error message if something went wrong', () => {
+        const throwError = true;
+        jsonfile.setup(throwError);
+
+        sut.writeFile('../test', {});
+        expect(chalk.red).toHaveBeenCalled();
+    });
+
+    test('should log a success message if everything went well', () => {
+        jsonfile.setup(false);
+
+        sut.writeFile('../test', {});
+        expect(chalk.green).toHaveBeenCalledWith(
+            'Order successfully written to file'
+        );
+    });
+});

src/waiter.spec.js

@@ -0,0 +1,28 @@
+const chalk = require('chalk');
+const sut = require('./waiter');
+
+describe('Waiter', () => {
+    beforeAll(() => (console.log = jest.fn()));
+
+    test('should print the food on the order', () => {
+        const food = 'Pizza';
+        const drink = 'Coke';
+        sut.placeOrder(food, drink);
+
+        expect(chalk.green).toHaveBeenCalledWith(
+            'You ordered the following food: '
+        );
+        expect(chalk.blue.bold).toHaveBeenCalledWith(food);
+    });
+
+    test('should print the drink to the order', () => {
+        const food = 'Pizza';
+        const drink = 'Coke';
+        sut.placeOrder(food, drink);
+
+        expect(chalk.green).toHaveBeenCalledWith(
+            'You ordered the following drink: '
+        );
+        expect(chalk.blue.bold).toHaveBeenCalledWith(drink);
+    });
+});