Add the last integration test

Author: vfarah-if

test-pnpm/uswitch/uswitch.should.test.ts

@@ -0,0 +1,100 @@
+import { readPlansFromFile } from './readPlansFromFile';
+import { EnergyPlan } from './calculateAnnualCost';
+import { main } from './uswitch';
+import readline from 'readline/promises';
+
+jest.mock('./readPlansFromFile');
+jest.mock('readline/promises', () => ({
+  createInterface: jest.fn(),
+}));
+type ReadLineInterfaceMock = {
+  prompt: jest.Mock;
+  on: jest.Mock;
+  close: jest.Mock;
+};
+describe('uswitch integration', () => {
+  let originalArgv;
+  let mockPlans: EnergyPlan[];
+  let mockConsoleLog: jest.SpyInstance;
+  let mockConsoleError: jest.SpyInstance;
+  let mockConsoleDebug: jest.SpyInstance;
+  let mockProcessExit: jest.SpyInstance;
+  let mockReadlineInterface: ReadLineInterfaceMock;
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+
+    mockPlans = [
+      {
+        supplier: 'sse',
+        plan: 'standard',
+        rates: [{ price: 13.5, threshold: 150 }, { price: 11.1, threshold: 100 }, { price: 10 }],
+        standing_charge: 9,
+      } as EnergyPlan,
+    ];
+
+    mockReadlineInterface = {
+      prompt: jest.fn(),
+      on: jest.fn(),
+      close: jest.fn(),
+    };
+
+    (readline.createInterface as jest.Mock).mockReturnValue(mockReadlineInterface);
+
+    mockConsoleLog = jest.spyOn(console, 'log').mockImplementation();
+    mockConsoleError = jest.spyOn(console, 'error').mockImplementation();
+    mockConsoleDebug = jest.spyOn(console, 'debug').mockImplementation();
+    mockProcessExit = jest.spyOn(process, 'exit').mockImplementation();
+
+    (readPlansFromFile as jest.Mock).mockResolvedValue(mockPlans);
+    originalArgv = process.argv;
+  });
+
+  afterEach(() => {
+    process.argv = originalArgv;
+  });
+
+  test('should exit if no file argument is provided', async () => {
+    process.argv = ['node', 'uswitch.ts'];
+
+    await main();
+
+    expect(mockConsoleError).toHaveBeenCalledWith('Usage: uswitch plans.json');
+    expect(mockProcessExit).toHaveBeenCalledWith(1);
+  });
+
+  describe('and when tring to add a price or cancelling', () => {
+    let lineHandler: ((line: string) => void) | undefined;
+    let closeHandler: (() => void) | undefined;
+
+    beforeEach(() => {
+      process.argv = ['node', 'uswitch.ts', 'plans.json'];
+      mockReadlineInterface.on.mockImplementation((event: string, handler: unknown) => {
+        if (event === 'line') lineHandler = handler as (line: string) => void;
+      });
+      mockReadlineInterface.on.mockImplementation((event: string, handler: unknown) => {
+        if (event === 'line') lineHandler = handler as (line: string) => void;
+        if (event === 'close') closeHandler = handler as () => void;
+      });
+    });
+
+    test('should read plans and handle user input', async () => {
+      await main();
+
+      expect(readPlansFromFile).toHaveBeenCalledWith('plans.json');
+      lineHandler('price 1000');
+      expect(mockConsoleLog).toHaveBeenCalledWith('sse,standard,146.16');
+    });
+
+    test('should read plans and close', async () => {
+      await main();
+
+      expect(readPlansFromFile).toHaveBeenCalledWith('plans.json');
+      lineHandler('exit');
+      if (closeHandler) {
+        closeHandler();
+        expect(mockConsoleDebug).toHaveBeenCalledWith('Well done!');
+      }
+    });
+  });
+});

test-pnpm/uswitch/uswitch.ts

@@ -3,7 +3,7 @@ import { commandHandler } from './commandHandler';
 import { readPlansFromFile } from './readPlansFromFile';
 import readline from 'readline/promises';
 
-async function main() {
+export async function main() {
   const file = process.argv[2];
   if (!file) {
     console.error('Usage: uswitch plans.json');
@@ -26,7 +26,10 @@ async function main() {
   // }
 }
 
-main();
+// Only run main if this file is being run directly
+if (require.main === module) {
+  main();
+}
 
 function promptUserForPrices(rl: readline.Interface, plans: EnergyPlan[]): void {
   rl.prompt();