lab2 finish

lab2/main_test.js

@@ -1,6 +1,110 @@
+const fs = require('fs');
 const test = require('node:test');
 const assert = require('assert');
-const { Application, MailSystem } = require('./main');
 
 // TODO: write your tests here
-// Remember to use Stub, Mock, and Spy when necessary
+// Remember to use Stub, Mock, and Spy when necessary
+
+// mock fs.readFile to simulate the file content before import main.js
+test.mock.method(fs, 'readFile', (path, encoding, callback) => {
+    callback(null, test_file_data);
+});
+const { Application, MailSystem } = require('./main');
+const { type } = require('os');
+
+const test_people = ['Alice', 'Bob', 'Charlie'];
+const test_file_data = test_people.join('\n');
+
+test('MailSystem.write', () => {
+    const mailSystem = new MailSystem();
+    const name = test_people[0];
+    const expected = 'Congrats, ' + name + '!';
+
+    const context = mailSystem.write(name);
+    assert.strictEqual(context, expected);
+});
+
+test('MailSystem.send', () => {
+    const mailSystem = new MailSystem();
+    const name = test_people[0];
+    const context = 'Congrats, ' + name + '!';
+
+    // use test.mock to simulate Math.random() with return value = 1
+    test.mock.method(Math, 'random', () => 1);
+    let success = mailSystem.send(name, context);
+    assert.strictEqual(success, true);
+
+    // use test.mock to simulate Math.random() with return value = 0
+    test.mock.method(Math, 'random', () => 0);
+    success = mailSystem.send(name, context);
+    assert.strictEqual(success, false);
+
+    test.mock.restoreAll();
+});
+
+test('Application.getNames', async () => { 
+    const application = new Application();
+
+    const [people, selected] = await application.getNames();
+    assert.deepStrictEqual(people, test_people); 
+    assert.deepStrictEqual(selected, []);
+});
+
+test('Application.getRandomPerson', async () => {
+    const application = new Application();
+    const [people, selected] = await application.getNames();
+
+    test.mock.method(Math, 'random', () => 0);
+    const person = application.getRandomPerson();
+    assert.strictEqual(person, test_people[0]);
+
+    test.mock.restoreAll();
+});
+
+test('Application.selectNextPerson', async () => {
+    const application = new Application();
+    const [people, selected] = await application.getNames();
+
+    test.mock.method(Math, 'random', () => 0);
+    const person = application.selectNextPerson();
+    assert.strictEqual(person, test_people[0]);
+
+    // for the case when getRandomPerson returns the person that has already been selected
+    let dup = true;
+    test.mock.method(application, 'getRandomPerson', () => {
+        // return the person already selected once and return another person next time
+        if (dup) {
+            dup = false;
+            return test_people[0];
+        } else {
+            return test_people[1];
+        }
+    });
+    const person_after_dup = application.selectNextPerson();
+
+    // reset test.mock
+    test.mock.restoreAll();
+    // select all people (except the two which are already selected before)
+    for (let i = 0; i < people.length-2; i++) {
+        let person_temp = application.selectNextPerson();
+    }
+
+    // when all people are already selected
+    const person_null = application.selectNextPerson();
+    assert.strictEqual(person_null, null);
+
+});
+
+test ('Application.notifySelected', async () => {
+    const application = new Application();
+    const [people, selected] = await application.getNames();
+
+    test.mock.method(Math, 'random', () => 0);
+    const person = application.selectNextPerson();
+
+    // set random to 1 to simulate mail sent successfully
+    test.mock.method(Math, 'random', () => 1);
+    application.notifySelected();
+
+    test.mock.restoreAll();
+});