Basic testing

src/01-simple-tests/index.test.ts

@@ -1,32 +1,53 @@
 // Uncomment the code below and write your tests
-// import { simpleCalculator, Action } from './index';
+import { simpleCalculator, Action } from './index';
 
 describe('simpleCalculator tests', () => {
   test('should add two numbers', () => {
     // Write your test here
+    const input = { a: 2, b: 3, action: Action.Add };
+    const result = simpleCalculator(input);
+    expect(result).toBe(5);
   });
 
   test('should subtract two numbers', () => {
     // Write your test here
+    const input = { a: 3, b: 2, action: Action.Subtract };
+    const result = simpleCalculator(input);
+    expect(result).toBe(1);
   });
 
   test('should multiply two numbers', () => {
     // Write your test here
+    const input = { a: 3, b: 4, action: Action.Multiply };
+    const result = simpleCalculator(input);
+    expect(result).toBe(12);
   });
 
   test('should divide two numbers', () => {
     // Write your test here
+    const input = { a: 12, b: 4, action: Action.Divide };
+    const result = simpleCalculator(input);
+    expect(result).toBe(3);
   });
 
   test('should exponentiate two numbers', () => {
     // Write your test here
+    const input = { a: 12, b: 2, action: Action.Exponentiate };
+    const result = simpleCalculator(input);
+    expect(result).toBe(144);
   });
 
   test('should return null for invalid action', () => {
     // Write your test here
+    const input = { a: 12, b: 2, action: 'divide' };
+    const result = simpleCalculator(input);
+    expect(result).toBeNull();
   });
 
   test('should return null for invalid arguments', () => {
     // Write your test here
+    const input = { a: '12', b: 2, action: Action.Add };
+    const result = simpleCalculator(input);
+    expect(result).toBeNull();
   });
 });

src/02-table-tests/index.test.ts

@@ -1,17 +1,39 @@
 // Uncomment the code below and write your tests
-/* import {  simpleCalculator, Action } from './index';
+import { Action, simpleCalculator } from './index';
 
 const testCases = [
-    { a: 1, b: 2, action: Action.Add, expected: 3 },
-    { a: 2, b: 2, action: Action.Add, expected: 4 },
-    { a: 3, b: 2, action: Action.Add, expected: 5 },
-    // continue cases for other actions    
-]; */
+  { a: 1, b: 2, action: Action.Add, expected: 3 },
+  { a: 2, b: 2, action: Action.Add, expected: 4 },
+  { a: 3, b: 2, action: Action.Add, expected: 5 },
+  // continue cases for other actions
+  { a: 3, b: 2, action: Action.Subtract, expected: 1 },
+  { a: 3, b: 3, action: Action.Subtract, expected: 0 },
+  { a: 9, b: 6, action: Action.Subtract, expected: 3 },
+  { a: 2, b: 2, action: Action.Multiply, expected: 4 },
+  { a: 8, b: 2, action: Action.Multiply, expected: 16 },
+  { a: 3, b: 2, action: Action.Multiply, expected: 6 },
+  { a: 12, b: 4, action: Action.Divide, expected: 3 },
+  { a: 8, b: 2, action: Action.Divide, expected: 4 },
+  { a: 9, b: 3, action: Action.Divide, expected: 3 },
+  { a: 12, b: 2, action: Action.Exponentiate, expected: 144 },
+  { a: 2, b: 3, action: Action.Exponentiate, expected: 8 },
+  { a: 3, b: 2, action: Action.Exponentiate, expected: 9 },
+  // Invalid cases
+  { a: 12, b: 2, action: 'divide', expected: null },
+  { a: 12, b: 2, action: 'multiply', expected: null },
+  { a: 110, b: 2, action: 'add', expected: null },
+  { a: '112', b: '2', action: Action.Add, expected: null },
+  { a: '113', b: '20', action: Action.Multiply, expected: null },
+  { a: '114', b: '28', action: Action.Divide, expected: null },
+];
 
 describe('simpleCalculator', () => {
   // This test case is just to run this test suite, remove it when you write your own tests
-  test('should blah-blah', () => {
-    expect(true).toBe(true);
-  });
+  test.each(testCases)(
+    'given a: $a, b: $b, action: $action, returns $expected',
+    ({ a, b, action, expected }) => {
+      expect(simpleCalculator({ a, b, action })).toBe(expected);
+    },
+  );
   // Consider to use Jest table tests API to test all cases above
 });

src/03-error-handling-async/index.test.ts

@@ -1,30 +1,43 @@
 // Uncomment the code below and write your tests
-// import { throwError, throwCustomError, resolveValue, MyAwesomeError, rejectCustomError } from './index';
+import {
+  throwError,
+  throwCustomError,
+  resolveValue,
+  MyAwesomeError,
+  rejectCustomError,
+} from './index';
 
 describe('resolveValue', () => {
   test('should resolve provided value', async () => {
     // Write your test here
+    const result = await resolveValue('Hello, World!');
+    expect(result).toBe('Hello, World!');
   });
 });
 
 describe('throwError', () => {
   test('should throw error with provided message', () => {
     // Write your test here
+    const PROVIDED_MESSAGE = 'Invalid input';
+    expect(() => throwError(PROVIDED_MESSAGE)).toThrow(PROVIDED_MESSAGE);
   });
 
   test('should throw error with default message if message is not provided', () => {
     // Write your test here
+    expect(() => throwError()).toThrow('Oops!');
   });
 });
 
 describe('throwCustomError', () => {
   test('should throw custom error', () => {
     // Write your test here
+    expect(() => throwCustomError()).toThrow(MyAwesomeError);
   });
 });
 
 describe('rejectCustomError', () => {
   test('should reject custom error', async () => {
     // Write your test here
+    await expect(rejectCustomError()).rejects.toThrow(MyAwesomeError);
   });
 });

src/04-test-class/index.test.ts

@@ -1,44 +1,99 @@
 // Uncomment the code below and write your tests
-// import { getBankAccount } from '.';
+jest.mock('lodash', () => ({
+  random: jest.fn(),
+}));
+
+import { random } from 'lodash';
+import {
+  getBankAccount,
+  InsufficientFundsError,
+  SynchronizationFailedError,
+  TransferFailedError,
+} from '.';
+
+const mockedRandom = jest.mocked(random);
 
 describe('BankAccount', () => {
+  afterEach(() => {
+    mockedRandom.mockReset();
+  });
+
   test('should create account with initial balance', () => {
     // Write your test here
+    const account = getBankAccount(10);
+    expect(account.getBalance()).toBe(10);
   });
 
   test('should throw InsufficientFundsError error when withdrawing more than balance', () => {
     // Write your test here
+    const account = getBankAccount(10);
+    expect(() => account.withdraw(20)).toThrow(InsufficientFundsError);
   });
 
   test('should throw error when transferring more than balance', () => {
     // Write your test here
+    const account = getBankAccount(10);
+    const secondAccount = getBankAccount(10);
+    expect(() => account.transfer(20, secondAccount)).toThrow(
+      InsufficientFundsError,
+    );
   });
 
   test('should throw error when transferring to the same account', () => {
     // Write your test here
+    const account = getBankAccount(10);
+    expect(() => account.transfer(20, account)).toThrow(TransferFailedError);
   });
 
   test('should deposit money', () => {
     // Write your test here
+    const account = getBankAccount(10);
+    account.deposit(20);
+    expect(account.getBalance()).toBe(30);
   });
 
   test('should withdraw money', () => {
     // Write your test here
+    const account = getBankAccount(30);
+    account.withdraw(10);
+    expect(account.getBalance()).toBe(20);
   });
 
   test('should transfer money', () => {
     // Write your test here
+    const account = getBankAccount(30);
+    const secondAccount = getBankAccount(10);
+    account.transfer(10, secondAccount);
+    expect(account.getBalance()).toBe(20);
+    expect(secondAccount.getBalance()).toBe(20);
   });
 
   test('fetchBalance should return number in case if request did not failed', async () => {
     // Write your tests here
+    const account = getBankAccount(30);
+    mockedRandom.mockReturnValueOnce(38).mockReturnValueOnce(1);
+    const balance = await account.fetchBalance();
+    expect(typeof balance).toBe('number');
+    expect(balance).not.toBeNull();
+    expect(balance).toBe(38);
   });
 
   test('should set new balance if fetchBalance returned number', async () => {
     // Write your tests here
+    const account = getBankAccount(30);
+    mockedRandom.mockReturnValueOnce(88).mockReturnValueOnce(1);
+    await account.synchronizeBalance();
+    expect(typeof account.getBalance()).toBe('number');
+    expect(account.getBalance()).not.toBeNull();
+    expect(account.getBalance()).toBe(88);
   });
 
   test('should throw SynchronizationFailedError if fetchBalance returned null', async () => {
     // Write your tests here
+    const account = getBankAccount(30);
+    mockedRandom.mockReturnValueOnce(13).mockReturnValueOnce(0);
+    await expect(account.synchronizeBalance()).rejects.toThrow(
+      SynchronizationFailedError,
+    );
   });
 });

src/05-partial-mocking/index.test.ts

@@ -1,8 +1,16 @@
 // Uncomment the code below and write your tests
-// import { mockOne, mockTwo, mockThree, unmockedFunction } from './index';
+import { mockOne, mockTwo, mockThree, unmockedFunction } from './index';
 
 jest.mock('./index', () => {
-  // const originalModule = jest.requireActual<typeof import('./index')>('./index');
+  const originalModule =
+    jest.requireActual<typeof import('./index')>('./index');
+
+  return {
+    ...originalModule,
+    mockOne: jest.fn(),
+    mockTwo: jest.fn(),
+    mockThree: jest.fn(),
+  };
 });
 
 describe('partial mocking', () => {
@@ -12,9 +20,25 @@ describe('partial mocking', () => {
 
   test('mockOne, mockTwo, mockThree should not log into console', () => {
     // Write your test here
+    const consoleSpy = jest.spyOn(console, 'log').mockImplementation(() => {});
+
+    mockOne();
+    mockTwo();
+    mockThree();
+
+    expect(mockOne).toHaveBeenCalled();
+    expect(mockTwo).toHaveBeenCalled();
+    expect(mockThree).toHaveBeenCalled();
+
+    expect(consoleSpy).not.toHaveBeenCalled();
+    consoleSpy.mockRestore();
   });
 
   test('unmockedFunction should log into console', () => {
     // Write your test here
+    const consoleSpy = jest.spyOn(console, 'log').mockImplementation(() => {});
+    unmockedFunction();
+    expect(consoleSpy).toHaveBeenCalledWith('I am not mocked');
+    consoleSpy.mockRestore();
   });
 });