Assignment: Basic testing

package.json

@@ -11,7 +11,8 @@
     "format": "prettier --write \"src/**/*.ts\"",
     "lint": "eslint \"src/**/*.ts\" --fix",
     "test": "jest --silent",
-    "test:verbose": "jest",
+    "test:verbose": "jest --verbose --runInBand --detectOpenHandles",
+    "test:verbose:coverage": "jest --verbose --runInBand --detectOpenHandles --collectCoverage",
     "build": "tsc"
   },
   "devDependencies": {

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

@@ -11,9 +11,9 @@ describe('simpleCalculator tests', () => {
 
   test('should subtract two numbers', () => {
     // Write your test here
-    const [a, b] = [5, 10];
-    const result = simpleCalculator({ a: a, b: b, action: Action.Add });
-    expect(result).toBe(a + b);
+    const [a, b] = [10, 5];
+    const result = simpleCalculator({ a: a, b: b, action: Action.Subtract });
+    expect(result).toBe(a - b);
   });
 
   test('should multiply two numbers', () => {

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

@@ -1,17 +1,37 @@
 // Uncomment the code below and write your tests
-/* import {  simpleCalculator, Action } from './index';
+import { simpleCalculator, Action } 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 },
+
+  { a: 5, b: 1, action: Action.Subtract, expected: 4 },
+  { a: 4, b: 2, action: Action.Subtract, expected: 2 },
+  { a: 8, b: 3, action: Action.Subtract, expected: 5 },
+
+  { a: 2, b: 3, action: Action.Multiply, expected: 6 },
+  { a: 3, b: 4, action: Action.Multiply, expected: 12 },
+  { a: 5, b: 2, action: Action.Multiply, expected: 10 },
+
+  { a: 8, b: 2, action: Action.Divide, expected: 4 },
+  { a: 10, b: 5, action: Action.Divide, expected: 2 },
+  { a: 15, b: 3, action: Action.Divide, expected: 5 },
+
+  { a: 5, b: 2, action: Action.Exponentiate, expected: 25 },
+  { a: 3, b: 3, action: Action.Exponentiate, expected: 27 },
+  { a: 2, b: 5, action: Action.Exponentiate, expected: 32 },
+
+  // Invalid cases
+  { a: 2, b: 5, action: 'wrong action', expected: null },
+  { a: '2', b: 5, action: Action.Exponentiate, expected: null },
+  { a: 2, b: '5', action: Action.Exponentiate, expected: null },
+  // continue cases for other actions
+];
 
 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);
-  });
   // Consider to use Jest table tests API to test all cases above
+  test.each(testCases)('$a $action $b', ({ a, b, action, expected }) => {
+    expect(simpleCalculator({ a, b, action })).toBe(expected);
+  });
 });

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

@@ -1,30 +1,51 @@
 // 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
+    expect.assertions(1);
+    expect(resolveValue(10)).resolves.toBe(10);
   });
 });
 
 describe('throwError', () => {
   test('should throw error with provided message', () => {
     // Write your test here
+    const errMsg = 'Oops, error occured';
+    expect(() => {
+      throwError(errMsg);
+    }).toThrow(errMsg);
   });
 
   test('should throw error with default message if message is not provided', () => {
     // Write your test here
+    const defaultErrMsg = 'Oops!';
+    expect(() => {
+      throwError();
+    }).toThrow(defaultErrMsg);
   });
 });
 
 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
+    expect.assertions(1);
+    await expect(rejectCustomError()).rejects.toThrow(MyAwesomeError);
   });
 });

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

@@ -1,44 +1,125 @@
 // Uncomment the code below and write your tests
-// import { getBankAccount } from '.';
+import {
+  getBankAccount,
+  BankAccount,
+  InsufficientFundsError,
+  // SynchronizationFailedError,
+  TransferFailedError,
+  SynchronizationFailedError,
+} from '.';
+
+import { random } from 'lodash';
+
+jest.mock('lodash', () => ({
+  random: jest.fn(),
+}));
 
 describe('BankAccount', () => {
+  const initialBalance = 1000;
+
   test('should create account with initial balance', () => {
     // Write your test here
+    const account = getBankAccount(initialBalance);
+
+    expect(account).toBeInstanceOf(BankAccount);
+    expect(account.getBalance()).toBe(initialBalance);
   });
 
   test('should throw InsufficientFundsError error when withdrawing more than balance', () => {
     // Write your test here
+    const account = getBankAccount(initialBalance);
+
+    expect(() => {
+      account.withdraw(account.getBalance() + 1000);
+    }).toThrow(InsufficientFundsError);
   });
 
   test('should throw error when transferring more than balance', () => {
     // Write your test here
+    const account = getBankAccount(initialBalance);
+    const accountToTransfer = getBankAccount(initialBalance);
+
+    expect(() => {
+      account.transfer(account.getBalance() + 1000, accountToTransfer);
+    }).toThrow(InsufficientFundsError);
   });
 
   test('should throw error when transferring to the same account', () => {
     // Write your test here
+    const account = getBankAccount(initialBalance);
+
+    expect(() => {
+      account.transfer(account.getBalance() + 1000, account);
+    }).toThrow(TransferFailedError);
   });
 
   test('should deposit money', () => {
     // Write your test here
+    const account = getBankAccount(initialBalance);
+    const deposit = 2000;
+    account.deposit(deposit);
+
+    expect(account.getBalance()).toBe(initialBalance + deposit);
   });
 
   test('should withdraw money', () => {
     // Write your test here
+    const account = getBankAccount(initialBalance);
+    const withdrawAmount = 200;
+    account.withdraw(withdrawAmount);
+
+    expect(account.getBalance()).toBe(initialBalance - withdrawAmount);
   });
 
   test('should transfer money', () => {
     // Write your test here
+    const account = getBankAccount(initialBalance);
+    const accountToTransfer = getBankAccount(initialBalance);
+    const transferAmount = 300;
+    account.transfer(transferAmount, accountToTransfer);
+
+    expect(account.getBalance()).toBe(initialBalance - transferAmount);
+    expect(accountToTransfer.getBalance()).toBe(
+      initialBalance + transferAmount,
+    );
   });
 
   test('fetchBalance should return number in case if request did not failed', async () => {
     // Write your tests here
+
+    const account = getBankAccount(initialBalance);
+
+    (random as jest.Mock)
+      .mockImplementationOnce(() => 77)
+      .mockImplementationOnce(() => 1);
+
+    const balance = await account.fetchBalance();
+
+    expect(typeof balance).toBe('number');
   });
 
-  test('should set new balance if fetchBalance returned number', async () => {
+  test('synchronizeBalance should set new balance if fetchBalance returned number', async () => {
     // Write your tests here
+    const account = getBankAccount(initialBalance);
+    (random as jest.Mock)
+      .mockImplementationOnce(() => 77)
+      .mockImplementationOnce(() => 1);
+
+    await account.synchronizeBalance();
+    expect(account.getBalance()).not.toBe(initialBalance);
   });
 
-  test('should throw SynchronizationFailedError if fetchBalance returned null', async () => {
+  test('synchronizeBalance should throw SynchronizationFailedError if fetchBalance returned null', async () => {
     // Write your tests here
+    const account = getBankAccount(initialBalance);
+
+    (random as jest.Mock)
+      .mockImplementationOnce(() => 77)
+      .mockImplementationOnce(() => 0);
+
+    expect.assertions(1);
+    await expect(account.synchronizeBalance()).rejects.toThrow(
+      SynchronizationFailedError,
+    );
   });
 });

src/04-test-class/index.ts

@@ -39,7 +39,6 @@ export class BankAccount {
 
   public async fetchBalance(): Promise<number | null> {
     const balance = random(0, 100, false);
-
     const requestFailed = random(0, 1, false) === 0;
 
     return requestFailed ? null : balance;

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

@@ -1,20 +1,39 @@
 // 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 {
+    mockOne: jest.fn(),
+    mockTwo: jest.fn(),
+    mockThree: jest.fn(),
+    unmockedFunction: originalModule.unmockedFunction,
+  };
 });
 
 describe('partial mocking', () => {
   afterAll(() => {
     jest.unmock('./index');
   });
 
-  test('mockOne, mockTwo, mockThree should not log into console', () => {
+  test('mockOne, mockTwo, mockTwo should not log into console', () => {
     // Write your test here
+    const logSpy = jest.spyOn(console, 'log').mockImplementation(() => {});
+
+    mockOne();
+    mockTwo();
+    mockThree();
+
+    expect(logSpy).not.toHaveBeenCalled();
   });
 
   test('unmockedFunction should log into console', () => {
     // Write your test here
+    const logSpy = jest.spyOn(console, 'log').mockImplementation(() => {});
+    unmockedFunction();
+
+    expect(logSpy).toHaveBeenCalled();
   });
 });